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Occurrence of the entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana in soils from temperate and near-northern habitats
Abstract
The occurrence of deuteromycetous entomopathogenic fungi was examined in 266 soil samples representing 86 locations across temperate and near northern habitats in Ontario, Canada. Entomopathogenic fungi were isolated by baiting the soil with waxworm larvae, Galleria mellonella L., and incubating at 8, 15, or 25°C. Entomopathogenic fungi were isolated from 91% of the locations sampled across Ontario. The most abundant species were Metarhizium anisopliae (Metschn.) Sorok. (357 isolates) and Beauveria bassiana (Bals.) Vuill. (187 isolates). Thirteen isolates of Paecilomyces spp. were also found. Beauveria bassiana was isolated more frequently in soils from near northern locations, relative to M. anisopliae. Beauveria bassiana was isolated more frequently from larvae baited in soils incubated at 8 and 15°C, while M. anisopliae was isolated most frequently at 25°C. Thus, B. bassiana is more psychrophilic than M. anisopliae. From 47 of the locations in a temperate area (southern Ontario and the Kawartha Lakes region), two sites, one from an agricultural habitat and one from a natural habitat, were sampled within 1 km of each other. In these locations, B. bassiana was predominantly recovered more often from soils of natural habitats, while M. anisopliae was recovered more often in agricultural habitats. The occurrence of M. anisopliae and B. bassiana was not related to soil type or pH.Key words: Metarhizium, Beauveria, entomopathogenic fungi, fungal population biology, soil ecology.
... The dominance of B. bassiana in soils collected from various types of forests is also confirmed by studies conducted in Denmark [50], Finland [51], Poland [12,52,53], Japan [54], Italy [55], Spain [56,57], Austria [58], Mexico [59], Brazil [60], and Portugal [61]. In other research, Metarhizium was also the most abundant fungal genus detected [e.g., 31,35,58,62,63], with variable proportions of other species. Tkaczuk et al. [35,58] and Kleespies et al. [62] found that species from the genus Isaria was the second-most commonly detected fungus, with Beauveria in third place;Keller et al. [31] and Bidochka et al. [63] found that Beauveria was the second most prevalent genus, and Paecilomyces was the third. ...
... In other research, Metarhizium was also the most abundant fungal genus detected [e.g., 31,35,58,62,63], with variable proportions of other species. Tkaczuk et al. [35,58] and Kleespies et al. [62] found that species from the genus Isaria was the second-most commonly detected fungus, with Beauveria in third place;Keller et al. [31] and Bidochka et al. [63] found that Beauveria was the second most prevalent genus, and Paecilomyces was the third. Popowska-Nowak et al. [64] found that Metarhizium anisopliae (Metschn.) ...
... Species composition, frequency, and the number of colonies depends on different factors such as geographical location, type of habitat, microclimatic conditions (temperature and humidity), and time of year (which determines the activity of insects in the soil environment and the transfer of spores and other forms of fungal propagation) [11,12,51,63,64], as well as the use of chemical pesticides, especially fungicides that can change the occurrence, infectivity, and population dynamics of EPF in the soil [68,[88][89][90]. In general, EPF are more abundant in soils that have less disturbance [1,34,91]. ...
Entomopathogenic fungi (EPF) in Croatian forests are known only from observations of insect cadavers that show obvious signs of disease. To date, their presence in soils has not been investigated. The aim of this study was to investigate their occurrence, diversity, and distribution, and to assess their density in tested soils. Soil samples were collected during 2018, 2019, and 2020 at different localities throughout the country, and analyzed by using a method of isolation of fungi on selective culture media. To assess the density of EPF in tested soils, colonies of individual fungal species were counted and recorded; the results were expressed as the number of colony-forming units (CFU) per gram of dry soil. After morphological and molecular analysis, five entomopathogenic fungal genera were identified: Beauveria spp., Metarhizium spp., Purpureocillium spp., Lecanicillium spp., and Paecilomyces spp. Results also showed that the range of a total EPF colony density in the soil varies from 4 × 103 to 27.4 × 103 CFU g−1. The most common were EPF of the genus Beauveria, which were recorded at four of five locations, and at 16 of 25 sampling points, but the highest average number (density) of colonies belonged to the genus Metarhizium. Since this type of research was never conducted in Croatia previously, this is the first evidence that insect pathogenic fungi are present in soils of different natural forest habitats. Such research can be useful in selecting and utilizing entomopathogens that are suitable for biological pest control in certain target areas.
... The soil environment constitutes an important reservoir for a diversity of EPFs, which can contribute significantly to the regulation of insect populations (Keller and Zimmermann 1989). EPFs can interact with arthropod hosts as parasites or saprotrophs (Bidochka et al. 1998;Charnley and Collins 2007). Hypocrealean EPFs, belonging to the genera Beauveria, Isaria and Metarhizium, occur worldwide in the soil, including natural and agricultural areas and have the greatest potential for biological control (Bidochka et al. 1998;Meyling and Eilenberg 2006;McGuire and Northfield 2020;Bueno-Pallero et al. 2020). ...
... EPFs can interact with arthropod hosts as parasites or saprotrophs (Bidochka et al. 1998;Charnley and Collins 2007). Hypocrealean EPFs, belonging to the genera Beauveria, Isaria and Metarhizium, occur worldwide in the soil, including natural and agricultural areas and have the greatest potential for biological control (Bidochka et al. 1998;Meyling and Eilenberg 2006;McGuire and Northfield 2020;Bueno-Pallero et al. 2020). These kinds of fungi are unique organisms that are capable of infecting their hosts directly through the exoskeleton, while other entomopathogens (viruses and bacteria) must be ingested with food to infect the host (Augustyniuk-Kram and Kram 2012). ...
... Therefore, knowledge of the occurrence and species composition of EPFs in the soil environment is very important, especially the native EPFs population. Most studies of the occurrence and biodiversity of EPFs in soils have focused on differences in species composition between areas defined by habitat types (Vänninen 1996;Steenberg 1997;Bidochka et al. 1998;Klingen et al. 2002;Keller et al. 2003;Eilenberg 2006, 2007;Prenerová et al. 2009;Bueno-Pallero et al. 2020;Sharma et al. 2020). Several methods to isolate EPFs from the soil have been used. ...
Bulb crops are attacked by various soil-dwelling pests and pathogens. Entomopathogenic (EPFs) and mycoparasitic fungi (MPFs) which are distributed in natural and agricultural soils worldwide can play an important role as natural enemies of bulb pests. The species richness and density of these fungi in onion and garlic fields have not been investigated. The aim of this study was to determine the occurrence of EPFs and MPFs in soils where these crops were grown and compared the data from sites of the Czech Republic and Israel. Methods of fungi isolation and quantification were based on elution of soil samples by water and cultivation using selective media with dodine for EPFs and cultivation using potato dextrose agar with chloramphenicol for MPFs. Entomopathogenic fungi Beauveria spp., Isaria spp., Lecanicillium spp., Metarhizium spp., Purpureocillium spp. and mycoparasitic fungi Trichoderma spp. were isolated from soil samples in both countries. The highest density was observed in the genus Metarhizium in both countries. Metarhizium spp. were most abundant in the site Mlýn Podhora in the Czech Republic. The average density of colony-forming units (CFU) per 1 mL of soil sample was 1.47 × 10 4. The lowest density was observed in the genus Beauveria in both countries, up to 5.93 × 10 2 CFU per 1 mL of soil sample. Soils in the Czech Republic contained about ten times higher number of EPFs compared to Israel. Rather higher prevalence of MPFs was also found in the Czech Republic. Possible reasons for within and between countries variability in EPFs and MPFs occurrence are discussed.
... Ignoffo e Garcia (1992), destacaram que a umidade é um requisito fundamental para a germinação de conídios e sobrevivência de fungos entomopatogênicos. De acordo com Keller e Bidochka (1998), um solo com umidade reduzida pode contribuir para o decréscimo na abundância de fungos. Krueger & Roberts (1997), reportaram o solo como um ambiente favorável aos fungos entomopatogênicos devido à umidade alta e estável. ...
... Embora não consistentemente assim, M. anisopliae parece ser mais frequente em solos de habitats cultivados. Esta observação tem sido interpretada como as populações de M. anisopliae mostram mais resistência à perturbação, que é uma característica dos habitats cultivados (BIDOCHKA et al, 1998;MEYLING & ELLENBERG, 2007). Em florestas tropicais, M. anisopliae pode ser facilmente isolado a partir de amostras de solo usando larvas de G. mellonella e larvas de T. molitor (HUGHES et al., 2004). ...
... Todos os fungos encontrados neste estudo também foram registrados em outras partes do mundo (VANNINEN et al., 1989;VANNINEN et al, 1995;BIDOCHKA et al., 1998;MEYLING & EILENBERG, 2006;AUNG et al., 2008;SUN et al., 2008;MEYLING et al., 2011). A prevalência de espécies de Beauveria em habitats naturais tem sido estudada na Europa (MIETKIEWSKI et al., 1991;STENZEL, 1992;VANNINEN, 1995;KLINGEN et al., 2002), na América (BIDOCHKA et al., 1998) e na Austrália (RATH et al, 1992. ...
... Ignoffo e Garcia (1992), destacaram que a umidade é um requisito fundamental para a germinação de conídios e sobrevivência de fungos entomopatogênicos. De acordo com Keller e Bidochka (1998), um solo com umidade reduzida pode contribuir para o decréscimo na abundância de fungos. Krueger & Roberts (1997), reportaram o solo como um ambiente favorável aos fungos entomopatogênicos devido à umidade alta e estável. ...
... Embora não consistentemente assim, M. anisopliae parece ser mais frequente em solos de habitats cultivados. Esta observação tem sido interpretada como as populações de M. anisopliae mostram mais resistência à perturbação, que é uma característica dos habitats cultivados (BIDOCHKA et al, 1998;MEYLING & ELLENBERG, 2007). Em florestas tropicais, M. anisopliae pode ser facilmente isolado a partir de amostras de solo usando larvas de G. mellonella e larvas de T. molitor (HUGHES et al., 2004). ...
... Todos os fungos encontrados neste estudo também foram registrados em outras partes do mundo (VANNINEN et al., 1989;VANNINEN et al, 1995;BIDOCHKA et al., 1998;MEYLING & EILENBERG, 2006;AUNG et al., 2008;SUN et al., 2008;MEYLING et al., 2011). A prevalência de espécies de Beauveria em habitats naturais tem sido estudada na Europa (MIETKIEWSKI et al., 1991;STENZEL, 1992;VANNINEN, 1995;KLINGEN et al., 2002), na América (BIDOCHKA et al., 1998) e na Austrália (RATH et al, 1992. ...
As unidades de conservação são espaços naturais de proteção da biodiversidade, com os mais variados objetivos de preservação, conservação e controle da exploração de recursos. Neste contexto, o Parque Natural Municipal do Curió (PNMC), localizado no município de Paracambi – RJ, destaca-se como o segundo maior parque municipal do estado do Rio de Janeiro, com uma área total de 913 hectares. O Parque conta com uma grande diversidade de fauna e flora, além da riqueza de recursos hídricos; tendo, portanto, diversas funções e serviços ecossistêmicos. Devido à esta importância local, o PNMC é uma importante unidade de conservação municipal, tendo em vista que este representa um dos poucos fragmentos remanescentes de Mata Atlântica em uma região fortemente impactada pela ação antrópica. relevo é o principal responsável pela fragilidade ambiental do Parque Natural Municipal do Curió. As principais classes de solos que ocorrem no Parque são Cambissolos, Argissolos e Latossolos, que apesar da maior profundidade quando formados em rampa de colúvio, são altamente suscetíveis ao processo erosivo, sendo imprescindível a conservação da flora, minimizando a degradação ambiental. A combinação do material de origem de natureza ácida e a condição de clima tropical são as principais responsáveis pela baixa fertilidade natural dos solos, sendo a ciclagem de nutrientes, fundamental para o equilíbrio do ecossistema e manutenção da vegetação.
... The use of Galleria mellonella Linnaeus (Lepidoptera: Pyralidae) for isolating EPF from soil or the "Galleria-bait method" was first described by Zimmermann [73]. Since then, it has been used for EPF isolations in many studies [74][75][76][77][78][79][80][81][82][83][84][85][86][87][88][89][90][91]. Tenebrio molitor Linnaeus (Coleoptera: Tenebrionidae) has also been used as a bait insect in some studies [92][93][94]. ...
... Organically managed farm and hedgerows with hawthorn, poplar, nettles, in Bakkegården, Denmark n/a GM [80] Conventional and organic corn field and soybean field; and field margins with grass strips in Iowa, USA Appendix A, Medium 14 (supplemented with 0.62 gL −1 dodine) GM [57] Agricultural habitat and natural habitat, Southern Ontario and the Kawartha Lakes region, Canada n/a GM [76] Cultivated habitats (olive and stone-fruit crops, horticultural crops, cereals crops, leguminous crops, and sunflower); and natural habitats (natural forests, pastures, riverbanks, and desert areas) in Spain and the Canary and the Balearic Archipelagos n/a GM [81] Three conventional citrus farms and three organic n/a C. capitata; T. [109] citrus farms in the Eastern Cape province, South Africa Hedgerows around an organic farming field, Bakkegården, Denmark n/a GM [128] Soils from grasses, Salix, and Betula community, Greenland n/a GM [107] Hedgerows in vineyards, Douro wine region, Portugal n/a GM [7] Vineyards in the states of New South Wales and Victoria, Australia n/a TM [127] B. ...
... Organically managed farm; Hedgerows with hawthorn, poplar, nettles in Bakkegården, Denmark n/a GM [80] Agricultural habitat and natural habitat, Southern Ontario and the Kawartha Lakes region, Canada n/a GM [76] Crop fields, meadows, hedgerows, and forests, n/a GM [97] Slovakia Darmstadt surroundings, Germany n/a GM [73] Natural and cultivated soils, Finland n/a Lecanicillium spp. ...
Entomopathogenic bacteria and fungi are quite frequently found in soils and insect ca-davers. The first step in utilizing these microbes as biopesticides is to isolate them, and several culture media and insect baiting procedures have been tested in this direction. In this work, the authors review the current techniques that have been developed so far, in the last five decades, and display brief protocols which can be adopted for the isolations of these entomopathogens. Among bacteria, this review focuses on Serratia spp. and bacteria from the class Bacilli. Among fungi, the review focuses those from the order Hypocreales, for example, genera Beauveria, Clonostachys, Lecanicillium, Metarhizium, and Purpureocillium. The authors chose these groups of entomopatho-genic bacteria and fungi based on their importance in the microbial biopesticide market.
... Besides, if applied as bio-pesticides, these strains can overcome environmental stress by improved adaptation to environmental conditions [6,12]. Several studies have reported that the tolerance of entomopathogenic fungi to climatic conditions is strongly related to its natural habitat [6,13,14]. ...
... The results also showed that the abundance of entomopathogenic fungi in soil requires a high organic matter content and moderate pH (around 8). Similar results have been reported by previous studies which revealed that entomopathogenic fungi are more abundant in soils with high organic matter content and pH around 8 [14,19,48]. This can be explained by the fact that soils with high organic matter content have an ecological balance with a low C/N ratio and a large diversity of arthropod and hosts on which entomopathogenic fungi can grow [10]. ...
... is correlated with the natural habitat and the origin of these microorganisms [6,14,17]. Accordingly, the development of an effective mycoinsecticide requires the selection of highly virulent isolates with high tolerance to the climatic conditions of the application area. Thus, the use of native isolates is preferable due to their adaptation to the climatic conditions of the region [10]. ...
Background: Studying the ecology of biocontrol-agents is a prerequisite to effectively control medfly (Ceratitis capitata (Diptera: Tephritidae)) with entomopathogenic fungi. In this context, factors affecting the occurrence and distribution of medfly-associated entomopathogenic-fungi were studied. Soil samples (22) were collected from natural and cultivated areas of Souss-region Morocco.
Results: A total of 260 fungal isolates belonging to 22 species and 10 genera were obtained by using medfly pupae as bait. Medfly-associated fungi were detected in all studied soils and pupae infection percentages ranged from 3.33% to 48%. Two genera, Fusarium and Beauveria were the most frequent with 83 isolates (32%) and 50 isolates (19.23%) respectively. Pathogenicity test of isolated species against medfly pupae showed high mortality rates up to 91% for some strains. Principal component analysis (PCA) demonstrated a strong influence of origin, physical, and chemical properties of soil on the abundance of these fungi. In general, medfly-associated fungi were more abundant in soils with moderate pH (7.5 to 8) having high sand and organic content. High relative humidity negatively influenced the abundance of these fungi. Both factors directly affected the fungal infection percentages in pupae. The response of fungi to these parameters varied among species. According to principal component analysis (PCA), the soils of argan fields and forests were more suitable for the development of medfly-associated fungi than citrus orchards.
Conclusions: These results guide identifying suitable soils for the effective application of entomopathogenic fungi as biological control agents. In summary, isolated indigenous strains seem to be a promising option to control C. capitata.
... Besides, if applied as bio-pesticides, these strains can overcome environmental stress by improved adaptation to environmental conditions [6,12]. Several studies have reported that the tolerance of entomopathogenic fungi to climatic conditions is strongly related to its natural habitat [6,13,14]. ...
... The results also showed that the abundance of entomopathogenic fungi in soil requires a high organic matter content and moderate pH (around 8). Similar results have been reported by previous studies which revealed that entomopathogenic fungi are more abundant in soils with high organic matter content and pH around 8 [14,19,48]. This can be explained by the fact that soils with high organic matter content have an ecological balance with a low C/N ratio and a large diversity of arthropod and hosts on which entomopathogenic fungi can grow [10]. ...
... is correlated with the natural habitat and the origin of these microorganisms [6,14,17]. Accordingly, the development of an effective mycoinsecticide requires the selection of highly virulent isolates with high tolerance to the climatic conditions of the application area. Thus, the use of native isolates is preferable due to their adaptation to the climatic conditions of the region [10]. ...
Background: Studying the ecology of biocontrol-agents is a prerequisite to effectively control medfly (Ceratitis capitata (Diptera: Tephritidae)) with entomopathogenic fungi. In this context, factors affecting the occurrence and distribution of medfly-associated entomopathogenic-fungi were studied. Soil samples (22) were collected from natural and cultivated areas of Souss-region Morocco.
Results: A total of 260 fungal isolates belonging to 22 species and 10 genera were obtained by using medfly pupae as bait. Medfly-associated fungi were detected in all studied soils and pupae infection percentages ranged from 3.33% to 48%. Two genera, Fusarium and Beauveria were the most frequent with 83 isolates (32%) and 50 isolates (19.23%) respectively. Pathogenicity test of isolated species against medfly pupae showed high mortality rates up to 91% for some strains. Principal component analysis (PCA) demonstrated a strong influence of origin, physical, and chemical properties of soil on the abundance of these fungi. In general, medfly-associated fungi were more abundant in soils with moderate pH (7.5 to 8) having high sand and organic content. High relative humidity negatively influenced the abundance of these fungi. Both factors directly affected the fungal infection percentages in pupae. The response of fungi to these parameters varied among species. According to principal component analysis (PCA), the soils of argan fields and forests were more suitable for the development of medfly-associated fungi than citrus orchards.
Conclusions: These results guide identifying suitable soils for the effective application of entomopathogenic fungi as biological control agents. In summary, isolated indigenous strains seem to be a promising option to control C. capitata.
... Besides, if applied as bio-pesticides, these strains can overcome environmental stress by improved adaptation to environmental conditions [6,12]. Several studies have reported that the tolerance of entomopathogenic fungi to climatic conditions is strongly related to its natural habitat [6,13,14]. ...
... The results also showed that the abundance of entomopathogenic fungi in soil requires a high organic matter content and moderate pH (around 8). Similar results have been reported by previous studies which revealed that entomopathogenic fungi are more abundant in soils with high organic matter content and pH around 8 [14,19,48]. This can be explained by the fact that soils with high organic matter content have an ecological balance with a low C/N ratio and a large diversity of arthropod and hosts on which entomopathogenic fungi can grow [10]. ...
... These two parameters probably increased the chance to isolate highly virulent pathogens against med y. Previous studies have proved that the ability of entomopathogenic fungi to tolerate extreme environmental factors in the eld (UV-radiation, water stress, and temperature variation) is correlated with the natural habitat and the origin of these microorganisms [6,14,17]. Accordingly, the development of an effective mycoinsecticide requires the selection of highly virulent isolates with high tolerance to the climatic conditions of the application area. Thus, the use of native isolates is preferable due to their adaptation to the climatic conditions of the region [10]. ...
Background: Studying the ecology of biocontrol-agents is a prerequisite to effectively control medfly (Ceratitis capitata (Diptera: Tephritidae)) with entomopathogenic fungi. In this context, factors affecting the occurrence and distribution of medfly-associated entomopathogenic-fungi were studied. Soil samples (22) were collected from natural and cultivated areas of Souss-region Morocco.
Results: A total of 260 fungal isolates belonging to 22 species and 10 genera were obtained by using medfly pupae as bait. Medfly-associated fungi were detected in all studied soils and pupae infection percentages ranged from 3.33% to 48%. Two genera, Fusarium and Beauveria were the most frequent with 83 isolates (32%) and 50 isolates (19.23%) respectively. Pathogenicity test of isolated species against medfly pupae showed high mortality rates up to 91% for some strains. Principal component analysis (PCA) demonstrated a strong influence of origin, physical, and chemical properties of soil on the abundance of these fungi. In general, medfly-associated fungi were more abundant in soils with moderate pH (7.5 to 8) having high sand and organic content. High relative humidity negatively influenced the abundance of these fungi. Both factors directly affected the fungal infection percentages in pupae. The response of fungi to these parameters varied among species. According to principal component analysis (PCA), the soils of argan fields and forests were more suitable for the development of medfly-associated fungi than citrus orchards.
Conclusions: These results guide identifying suitable soils for the effective application of entomopathogenic fungi as biological control agents. In summary, isolated indigenous strains seem to be a promising option to control C. capitata.
... Besides, if applied as bio-pesticides, these strains can overcome environmental stress by improved adaptation to environmental conditions [6,12]. Several studies have reported that the tolerance of entomopathogenic fungi to climatic conditions is strongly related to its natural habitat [6,13,14]. ...
... The results also showed that the abundance of entomopathogenic fungi in soil requires a high organic matter content and moderate pH (around 8). Similar results have been reported by previous studies which revealed that entomopathogenic fungi are more abundant in soils with high organic matter content and pH around 8 [14,19,48]. This can be explained by the fact that soils with high organic matter content have an ecological balance with a low C/N ratio and a large diversity of arthropod and hosts on which entomopathogenic fungi can grow [10]. ...
... These two parameters probably increased the chance to isolate highly virulent pathogens against medfly. Previous studies have proved that the ability of entomopathogenic fungi to tolerate extreme environmental factors in the field (UV-radiation, water stress, and temperature variation) is correlated with the natural habitat and the origin of these microorganisms [6,14,17]. Accordingly, the development of an effective mycoinsecticide requires the selection of highly virulent isolates with high tolerance to the climatic conditions of the application area. Thus, the use of native isolates is preferable due to their adaptation to the climatic conditions of the region [10]. ...
Background: Studying the ecology of biocontrol-agents is a prerequisite to effectively control medfly (C. capitata) with entomopathogenic fungi. In this context, factors affecting the occurrence and distribution of medfly-associated entomopathogenic-fungi were studied. Soil samples (22) were collected from natural and cultivated areas of Souss-region Morocco. Results: A total of 260 fungal isolates belonging to 22 species and 10 genera were obtained by using medfly pupae as bait. Medfly-associated fungi were detected in all studied soils and pupae infection percentages ranged from 3.33% to 48%. Two genera, Fusarium and Beauveria were the most frequent with 83 isolates (32%) and 50 isolates (19.23%) respectively. Pathogenicity test of isolated species against medfly pupae showed high mortality rates up to 91% for some strains. Principal component analysis (PCA) demonstrated strong influence of origin, physical and chemical properties of soil on the abundance of these fungi. In general, medfly-associated fungi were more abundant in soils with moderate pH (7.5 to 8) having high sand and organic content. High relative humidity negatively influenced the abundance of these fungi. Both factors directly affected the fungal infection percentages in pupae. The response of fungi to these parameters varied among species. According to principal component analysis (PCA) the soils of argan fields and forests were more suitable for the development of medfly-associated fungi than citrus orchards.
Conclusions: These results provide guidance on identifying suitable soils for effective application of entomopathogenic fungi as biological control agents. In summary, isolated indigenous strains seem to be a promising option to control C. capitata.
... The most widely used approach for the isolation of EFs in soils is baiting with susceptible insects (Zimmermann, 1986). The wax moth larvae, Galleria mellonella (Lepidoptera: Pyralidae) (Vänninen, 1996;Chandler et al., 1997;Bidochka et al., 1998;Klingen et al., 2002;Quesada-Moraga et al., 2007;Sun et al., 2008;Goble et al., 2010;Meyling et al., 2011;Hernández-Domínguez and Guzmán-Franco, 2017;Inglis et al., 2019), and mealworm, Tenebrio molitor (Coleoptera: Tenebrionidae) (Meyling and Eilenberg, 2006;Steinwender et al., 2014;Keyser et al., 2015;Korosi et al., 2019), are the most used bait species for the general sampling of fungal entomopathogens. The outcomes of the above-mentioned surveys of naturally occurring taxa of insect-associated fungi in soil habitats are presented in Table 1. ...
... E) (Figure 7). A few studies have reported that latitude was correlated with B. bassiana distribution, while longitude was correlated with M. anisopliae natural distribution (Bidochka et al., 1998;Quesada-Moraga et al., 2007;Garrido-Jurado et al., 2011). Our HTS results and, the Mantel tests verified that community dissimilarities increased significantly with geographical distance (the Mantel correlation = 0.228, P = 0.001). ...
... Thus, we inferred that geographical coordinates may be the factors that possibly influence insect-fungal pathogen community composition in the investigated sites. Data gathered by natural occurrence studies using bait insect species possibly underestimate not only the diversity and frequency of commonly occurring EF species but also that of rare taxa, such as the hypocrealean insect pathogens (Vänninen, 1996;Chandler et al., 1997;Bidochka et al., 1998Bidochka et al., , 2001Klingen et al., 2002;Ali-Shtayeh et al., 2003;Keller et al., 2003;Meyling and Eilenberg, 2006;Quesada-Moraga et al., 2007;Inglis et al., 2008Inglis et al., , 2019Sun et al., 2008;Goble et al., 2010;Medo and Cagáň, 2011;Meyling et al., 2011;Rocha et al., 2013;Wakil et al., 2013;Steinwender et al., 2014;Kepler et al., 2015;Keyser et al., 2015;Rezende et al., 2015;Hernández-Domínguez and Guzmán-Franco, 2017). Some of these studies have reported lineages of Metarhizium, Beauveria, and Isaria as the common pathogenic microorganisms found in soil environments ( Table 1). ...
A survey was carried out on forest soils and grassland soils from Hebei and Sichuan provinces using Tenebrio molitor larvae as a bait, and high-throughput DNA sequencing (HTS) of the fungal internal transcribed spacer-2 ribosomal DNA was used to monitor the natural distribution of three leading hypocrealean families of insect fungal pathogens (Clavicipitaceae, Cordycipitaceae, and Ophiocordycipitaceae). The occurrence of insect fungal pathogens in soil samples from 98 different sites was compared. The use of insect bait indicated that entomopathogenic fungi of the genus Metarhizium were predominant, followed by Beauveria and Isaria. Molecular characterization using the Mz_FG543 intergenic region revealed that the Metarhizium species pool was phylogenetically composed of three closely related species as follows; Metarhizium pingshaense (n = 74), Metarhizium robertsii (n = 51), and Metarhizium brunneum (n = 26), as well as one isolate which clustered with Metarhizium flavoviride. Nine potentially new phylogenetic species were delimited within the M. flavoviride species complex by sequencing of the 5′ elongation factor-1 alpha region locus. The Beauveria (n = 64) and Isaria (n = 5) isolates were characterized via sequence analyses of the Bloc region. An intergenic spacer phylogeny of the Beauveria isolate assemblage revealed the phylogenetic species within the Beauveria bassiana clade. Interestingly, the individuals of M. pingshaense (n = 18) and M. brunneum (n = 12) exhibited the presence of both mating types in Sichuan Province. Similarly, for the Beauveria isolates, reproductive mode assays demonstrated that all four B. bassiana subclades possessed bipolar outcrossing mating systems. Of these, 19 isolates contained two mating types, and the rest were fixed for single mating types, revealing opportunities for intra-lineage heterothallic mating. The HTS results showed a significantly higher occurrence of the Clavicipitaceae family and the Metarhizium genus in the soil samples. The Venn diagram showed Metarhizium anisopliae (senso lato), Isaria farinose, and B. bassiana as frequently abundant fungal pathogen operational taxonomic units (core) across sampling sites, while the baiting method showed that the genus of Isaria was isolated locally. The Mantel test verified that community dissimilarity increased significantly with geographical distance, suggesting that geographical coordinates are possible factors that influence the insect fungal pathogen community composition in the studied sites. This study is the first to highlight the usefulness of utilizing soil baiting and deep sequencing to investigate the population dynamics of entomopathogens in soil.
... Besides, if applied as bio-pesticides, these strains can overcome environmental stress by improved adaptation to environmental conditions [6,12]. Several studies have reported that the tolerance of entomopathogenic fungi to climatic conditions is strongly related to its natural habitat [6,13,14]. ...
... The results also showed that the abundance of entomopathogenic fungi in soil requires a high organic matter content and moderate pH (around 8). Similar results have been reported by previous studies which revealed that entomopathogenic fungi are more abundant in soils with high organic matter content and pH around 8 [14,19,48]. This can be explained by the fact that soils with high organic matter content have an ecological balance with a low C/N ratio and a large diversity of arthropod and hosts on which entomopathogenic fungi can grow [10]. ...
... These two parameters probably increased the chance to isolate highly virulent pathogens against medfly. Previous studies have proved that the ability of entomopathogenic fungi to tolerate extreme environmental factors in the field (UV-radiation, water stress, and temperature variation) is correlated with the natural habitat and the origin of these microorganisms [6,14,17]. Accordingly, the development of an effective mycoinsecticide requires the selection of highly virulent isolates with high tolerance to the climatic conditions of the application area. Thus, the use of native isolates is preferable due to their adaptation to the climatic conditions of the region [10]. ...
Fungal isolates obtained from RSC corpses were identified by studying their macroscopic and microscopic aspects. Mycelial biomass was used for genomic DNA extraction according to kit protocol. Polymerase chain reaction (PCR) with specific primers on a partial sequence was used for each fungal isolate. Each PCR product was sequenced in the forward and reverse directions using an Applied Biosystem ABI 3130xl sequencer.
... However, higher recovery rates have been reported in other parts of the world. Bidochka et al. (1998) recovered 91% from temperate soils in Canada, and Keller et al. (2003) had a recovery rate of 96% from different habitats in Switzerland using the insect bait method in both natural and disturbed soils. The low recovery rate was also coupled with low species diversity as only two species of fungi were recovered. ...
... Soils harbouring Fusarium oxysporum were more commonly recovered from surrounding refugia, but the presence of M. anisopliae was more strongly associated with cultivated Honeybush fields. This is consistent with the findings of Bidochka et al. (1998) and Tkaczuk et al. (2013), who recovered more isolates and greater species richness in natural habitats over disturbed ecosystems. Occurrence of EPF is naturally associated with organic matter in the soil (Bidochka et al. 2001). ...
The southern and eastern parts of the African Fynbos region favour the production of honeybush tea. Honeybush biomass and extracts are used to prepare a beverage both locally and internationally, mainly as herbal tea with health benefits. Honeybush tea is mostly grown organically requiring natural control measures for pests and diseases. The leafhopper, Molopopterus sp., is one of the most important pests of cultivated honeybush in South Africa, as its feeding compromises the quality and quantity of the yield through leaf discolouration and reduction of the photosynthetic area. Local entomopathogenic fungi (EPF) can provide a pool of potential biocontrol agents for this pest. Therefore, a total of 98 soil samples were collected from organically grown honeybush fields and vegetation surrounding the honeybush fields in the Western Cape province of South Africa. Entomopathogenic fungi were isolated using the insect bait method and were characterised using molecular techniques. Twenty fungal isolates of Metarhizium anisopliae and Fusarium oxysporum were recovered from soil samples, of which 70% were from honeybush fields and 30% were from surrounding vegetation. Fusarium oxysporum isolates comprised 20% of the recovered isolates; M. anisopliae the remainder. Laboratory bioassays of the recovered isolates against adults and nymphs of the leafhopper, showed that F. oxysporum isolates caused 10–45% mortality and M. anisopliae isolates 30–80% mortality. Metarhizium anisopliae isolates J S1, KF S3, KF S11, KF S13, LS1 and LS2 were the most virulent and induced over 60% mortality in both nymphs and adults at a concentration of 1 × 107 conidia/ml.
... (Hypocreales: Clavicipitaceae) (Chandler et al., 1997;Bidochka et al., 1998;Klingen et al., 2002;Vega et al., 2009;Rudeen et al., 2013;Zuluaga-Cárdenas et al., 2015;Gebremariam et al., 2021), los cuales utilizan el suelo como hábitat para la persistencia a largo plazo (Hajek y Leger, 1994;Qayyum et al., 2021). En las huertas seleccionadas para este estudio no existen antecedentes de la introducción previa de agentes microbianos de control biológico, de las muestras de suelo recolectadas en campo se logró detectar a las especies Beauveria sp. ...
... La presencia de Metarhizium sp. en las parcelas estudiadas se explica por el hecho de ser una especie adaptada a las condiciones de labranza en áreas cultivadas como refieren varios autores (Bidochka et al., 1998;Bruck, 2004;Meyling y Eilenberg, 2006;Quesada-Moraga et al., 2007;Fisher et al., 2011;Wyrebek et al., 2011); y su resistencia a las altas temperaturas y la luz ultravioleta (Couceiro et al., 2021). Mientras que Beauveria solo se encontró en las áreas cercanas a los bordes, como se observó en los huertos la Piedra rajada y el Guardián, ya que es un hongo que prefiere los suelos no cultivados y ambientes forestales, y podría explicar los pocos aislados recuperados. ...
Background: Entomopathogenic fungi (EF) play a key role in the regulation of arthropod populations and
biotransformation in natural systems, as well as biological pest control agents in different agroecosystems, including
avocado cultivation (Persea americana Mill.), where Mexico is a leader in production and export worldwide.
Objective: Determine the presence of EF in soil in commercial avocado orchards in the state of Colima, Mexico.
Methodology: Sampling was carried out in three avocado orchards (Piedra rajada, El Guardián, and Montitlán) located
in Comala and Cuauhtémoc in the state of Colima, Mexico, from July 2016 to June 2017. Soil samples were collected
around avocado trees. Isolation of entomopathogenic fungi was performed using the Galleria mellonella Linnaeus
insect trap technique. The isolates were identified considering their micro- and macroscopic characteristics with the
taxonomic keys of Humber (2012). Results: A total of 108 samples were collected, of those, 120 isolates were obtained,
of which 112 belong to the genus Metarhizium and eight to Beauveria. Implications: The recovered fungi have a great
value for the avocado-growing areas of the state of Colima, either for the conservation of natural enemies of soil pests
or for their potential use as an alternative to synthetic insecticides. Conclusion: Knowing the native micro-biota of the
soil should be considered within biological pest control strategies, since it allows selecting the best adapted species,
and including sustainable alternatives for the environment.
... Clay in the soils may protect fungal blastospores from amoebic and bacterial attack (Jaronski 2007). However, for continued fungal viability, soil clay content appeared less important than other sometimes ill-defined biotic factors (Bidochka et al. 1998, Jaronski 2007. The presence of biotic inhibitors appears to exhibit a very important fungistatic role that is removed when insect chitin is encountered (Jaronski 2007). ...
... Ecologically, carbon sources are very limited in the soil when there is no plant-enriched rhizosphere; in contrast, insects are a rich source and likely serve as a preferred fungal carbon source. Similarly, essential nutrients (e.g., minerals and nitrogen) may be less accessible in soil than from insects (Reisinger et al. 1977, Bidochka et al. 1998, Behie et al. 2012. Evidence from the study of wild-type Beauveria from the Arctic and forested temperate areas, when compared to commercial agricultural products, suggests these former isolates are more cold adapted and retained greater UV light sensitivity, indicating a degree of regional strain adaptation (Sasan and Bidochka 2012). ...
Bubonic plague is a lethal bacterial disease of great historical importance. The plague organism, Yersinia pestis, is primarily transmitted by fleas (Siphonaptera). In natural settings, where its range expands, Y. pestis resides in association with wild rodents and their fleas (sylvatic plague). While chemical insecticides are used against plague vector fleas, biological approaches have not been as critically evaluated. Benign and cost-effective control methods are sorely needed, particularly where imperiled species are at risk. Here we explore the potential of two representative insect pathogenic fungi, Beauveria bassiana Vuillemin 1912 (Hypocreales: Cordycipitaceae) and Metarhizium anisopliae Metschnikoff 1879 (Hypocreales: Clavicipitaceae), each already used commercially worldwide in large-scale agricultural applications, as candidate biopesticides for application against fleas. We review the life cycles, flea virulence, commercial production, and field application of these fungi, and ecological and safety considerations. Pathogenic fungi infections among natural flea populations suggest that conditions within at least some rodent burrows are favorable, and laboratory studies demonstrate lethality of these fungi to at least some representative flea species. Continued study and advancements with these fungi, under appropriate safety measures, may allow for effective biocontrol of plague vector fleas to protect imperiled species, decrease plague outbreaks in key rodent species, and limit plague in humans.
... Fungi are the predominant natural pathogens of arthropods [1]. Hypocrealean entomopathogenic fungi (EPF), such as those in the genera Beauveria and Metarhizium, are natural inhabitants of most terrestrial ecosystems, including natural and agricultural areas [2][3][4]. EPF can interact with arthropod hosts as parasites or saprophytes [5]. During the parasitic phase, after the conidia infect the host, the fungus produces various compounds responsible for host death [6,7] and other secondary metabolites with an antibiotic or antagonistic response to defend the cadaver from opportunistic organisms [5,8,9]. ...
... Previous surveys found similar percentages, for example, 52% in the Pacific Northwest [60] and 72% in Spain [43]. However, EPF occurrence was quite variable in other studies, with only 20-30% of detections reported in the UK, Mexico, Turkey and Tasmania [16,[61][62][63] or over 90% in Ontario (Canada) and Switzerland [2,64]. Those frequencies are difficult to compare due to the lack of methodological uniformity among surveys. ...
Entomopathogenic fungi (EPF) are distributed in natural and agricultural soils worldwide. To investigate EPF occurrence in different botanical habitats and soil-ecoregions, we surveyed 50 georeferenced localities in the spring of 2016 across the Algarve region (South Portugal). Additionally, we compared three EPF isolation methods: insect baiting in untreated or pre-dried-soil and soil dilution plating on a selective medium. We hypothesized that forest habitats (oak and pine semi-natural areas) and the acidic soil ecoregion may favor EPF occurrence. Overall, EPF species were present in 68% of sites, widely distributed throughout the Algarve. The use of selective media resulted in higher recovery of EPF than did either soil-baiting method. Contrary to our hypothesis, neither vegetation type nor ecoregion appeared to influence EPF occurrence. Traditional and molecular methods confirmed the presence of five EPF species. Beauveria bassiana (34% of sites), was the most frequently detected EPF, using pre-dried soil baiting and soil dilution methods. However, baiting untreated soil recovered Fusarium solani more frequently (26% of sites), demonstrating the utility of using multiple isolation methods. We also found Fusarium oxysporum, Purpureocillium lilacinum and Metarhizium anisopliae in 14%, 8% and 2% of the sites, respectively. Three abiotic variables (pH, soil organic matter and Mg) explained 96% of the variability of the entomopathogen community (EPF and entomopathogenic nematodes) in a canonical correspondence analysis, confirming the congruence of the soil properties that drive the assemblage of both entomopathogens. This study expands the knowledge of EPF distribution in natural and cultivated Mediterranean habitats.
... It is crucial to research the distribution, isolation, and characterization of native EPF species (Bidochka et al. 1998), as exotic species/strains of EPFs have often failed in biocontrol programs due to factors relating to host species, or poor adaptability of exotic fungal strains to local environmental conditions (Lacey et al. 2015). Native EPF isolates may be more resistant to environmental changes and compatible with the ecosystem here than exogenous ones, which is a well-known fact (Kim and Kim 2008). ...
... It is crucial to research the distribution, isolation, and characterization of native EPF species (Bidochka et al. 1998), as exotic species/strains of EPFs have often failed in biocontrol programs due to factors relating to host species, or poor adaptability of exotic fungal strains to local environmental conditions (Lacey et al. 2015). Native EPF isolates may be more resistant to environmental changes and compatible with the ecosystem here than exogenous ones, which is a well-known fact (Kim and Kim 2008). ...
Entomopathogenic fungi (EPFs) are a significant group of insect pathogens that are used as microbial insecticides with distinct physiological mechanisms of pathogenicity. During our survey in the middle of March 2020 to early October 2022 on natural EPF as a biological control agent of the longhorn beetle (LHB) Osphranteria coerulescens, new isolates of EPFs were found on LHB larvae in apple orchards of Dargaz, Razavi Khorasan province, Iran. The nBLAST results of this these indigenous isolate indicated the highest similarity to Cladosporium sp. (Ascomycota: Davidiellaceae) with ON307222.1 access number and for EF-1α indicated the highest similarity to Cladosporium sp. with MH724951.1 access number. To assess the virulence of these indigenous isolates of EPF, a series of tests were conducted on the LHB larvae stages. Conidial concentrations 104, 105, 106, 107, and 108 (conidia/ml− 1) caused (10.21 ± 2.1), (23.44 ± 2.4), (28.72 ± 2.6), (33.23 ± 3.1) and (34.02 ± 2.8) % of mortality in LHB, respectively and there was no significant difference between 108 and 107 (conidia/ml−1) concentrations. The mortality results by the time showed that the process did not start until 3 days after treatment, and after that, it sped up. This research gathers new information about cryptic inhabiting larvae which shows considerable potential for this Cladosporium species to be implemented within the microbial control program of the LHB. This research is a new report isolating the pathogenicity of Cladosporium sp. on LHB. These fungal isolates have considerable potential for the microbiological control of the LHB.
... Exotic fungal isolates previously deployed against a variety of insect pests in different countries have often been unsatisfactory due to factors such as differences between hosts, isolates and climatic conditions [59,60]. Noting this constraint in the present study, we used native 15 EPF isolates of different developmental stages of R. ferrugineus. ...
The red palm weevil (RPW), Rhynchophorus ferrugineus (Olivier) (Coleoptera: Dryophthoridae), is a destructive and voracious pest of palm species worldwide. Due to environmental and regulatory concerns, ecologically safe alternatives to synthetic chemical insecticides are needed to manage this cryptic insect species. Entomopathogenic fungi have the potential to manage this pest. The scope of management and effectiveness can be improved by direct control or horizontal transmission of entomopathogenic fungal isolates. We tested in the laboratory the virulence and pathogenicity of fifteen different entomopathogenic fungal isolates belonging to the following species: Beauveria bassiana, Metarhizium anisopliae, Beauveria brongniartii and Purpureocillium lilacinum. All fungal isolates were found virulent against larvae (14.9 ± 1.06 to 81.5 ± 1.48% mortality) and adults (5.6 ± 1.12 to 51.7 ± 1.51% mortality) at 12 d post-treatment. From a screening bioassay, five M. anisopliae (WG-08, WG-09) and B. bassiana (WG-23, WG-24, WG-25) isolates were tested for their concentration response mortality against larvae and adults after 7, 14 and 21 days (d) of treatment. Mortality was found positively correlated with concentration and time. At 21 d of treatment, WG-23 and WG-25 1 × 108 conidia/mL resulted in 100% mortality against larvae while only WG-25 1 × 109 conidia/mL caused 100% mortality of adults. Along with mortality, all the potential isolates have strong ovicidal effects that reduced 81.49% at 1 × 108 conidia/mL. The horizontal transmission bioassay indicated that the infected adults transmitted the disease to healthy individuals. Horizontal transmission of fungi from infected to non-infected adults not only caused significant mortality but also had a serious sublethal impact on insect development and fitness including reduced number of eggs/d fecundity, egg viability and neonate survival. Isolate WG-25 reduced oviposition (0.5 eggs/d), fecundity (11.7 eggs/female), egg viability (11.6%) along with larval survival 25.9% when infected male mated with normal female. In semi-field trials, all fungal isolates reduced survival of larvae found inside the palms and ultimately reduced infestations over a period of two months. The results of this study indicate that entomopathogenic fungi should be further tested for sustainable and efficient control of RPW in date palm production systems.
... Soil-overwintering insects often construct chambers, like those built by S. albicosta, which may reduce multiple stressors that insects encounter while overwintering (Danks, 2004): physical damage in compacting soils (Sprague & Woods, 2015); drowning in soils flooded by spring snowmelt (Brust & Hoback, 2009) or rain (Hoback & Stanley, 2001;Woods & Lane, 2016); and infection by pathogens (Bidochka et al., 1998). We speculate that one or more of these stressors might explain the high proportion of missing or dead overwintering S. albicosta that we, and others observe in the field (cf. ...
Conserving energy through winter is important for the fitness of temperate insects. While insects can use buffered microhabitats, metabolic suppression or decreases in the thermal sensitivity of metabolic rate to override seasonal‐scale thermal trends, the relative importance of these strategies for limiting energy use by insects overwintering in soil remains underexplored.
We used a combined laboratory, field and simulation approach to investigate the overwintering energetics of the western bean cutworm (Striacosta albicosta), a univoltine lepidopteran pest of dry beans and corn that overwinters underground as a dormant prepupa.
We hypothesised that (1) the selection of thermally buffered microhabitats (i.e. deeper soil sites) reduces energy use in early autumn and late spring, and that (2) changes in the metabolic rate–temperature relationship reduce the impact of elevated temperatures on overwintering energy use.
We provide evidence that during the warmest parts of winter, dormant S. albicosta prepupae that had burrowed deep benefited from a cool, stable microclimate, whereas those near the soil surface appeared to rely on deeper metabolic suppression to maintain their energy stores.
Although elevated temperatures in the laboratory depleted their energy reserves, these strategies appear sufficient to limit energy drain under natural conditions in the field.
We suggest that small‐scale variation in the depth of soil refuges may mediate the interaction between the risk of energy drain and changes in the metabolic rate–temperature relationship in soil‐overwintering insects.
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... Steenberg (1995) suggested that in Danish soil, M. anisopliae is more common in open areas than in shady habitats (Meyling and Eilenberg 2007). Similarly , Bidochka et al. (1998) reported that M. anisopliae is more common in agricultural areas compared to forests in Canada, and B. bassiana is mostly found in shady and natural habitats such as forests. Contrary to these studies, Meyling and Eilenberg (2006) found that B. bassiana was also frequently seen in agricultural soil in a part of Denmark. ...
A total of 250 soil samples were taken from the forest, hazelnut, kiwi, vegetable, and meadow-rangeland areas in the coastal regions of Ordu province, Turkey. Entomopathogenic fungi were isolated from these soil samples using the Galleria-bait method. Eighty-five fungal isolates were isolated from these soil samples, after which they were morphologically and molecularly identified. After morphological characterization, 64 out of 85 isolates were identified molecularly. Based on the molecular characterization results, twenty-three out of the 64 isolates were Beauveria bassiana (35.94%), 11 isolates were Metarhizium brunneum (17.19%), 8 isolates were Metarhizium anisopliae (12.5%), 6 isolates were Metarhizium robertsii (9.38%), 4 isolates were Purpureocillium lilacinum (6.25%), 4 isolates were Clonostachys rogersoniana (6.25%), 3 isolates were Fusarium solani (4.69%), 1 isolate was Clonostachys rossmaniae (1.56%), 1 isolate was Aspergillus flavus (1.56%), 1 isolate was Cordyceps cicadae (1.56%), 1 isolate was Cordyceps fumosorosea (1.56%), and 1 isolate was Fusarium oxysporum (1.56%). In the coastal area of Ordu province, the most common entomopathogen fungal genus is Metarhizium followed by Beauveria bassiana.
... Coombes (2012) also highlights that M. anisopliaederived isolates tend to persist better under field conditions than do B. bassiana isolates. Such persistence is not exceptional, as the isolates derived from the M. anisopliae EPF species have been shown to be well adapted to surviving under fluctuating environmental conditions (Bidochka et al. 1998). ...
Entomopathogenic fungi (EPF) are cosmopolitan soil borne pathogens that cause epizootics in various insect orders. EPF isolates of Metarhizium brunneum and M. pinghaense have shown the potential for use as biological agents of important agricultural insect pests. The aim of the current study was to test for the persistence of M. brunneum and M. pinghaense on apple bark over a period of three weeks, under laboratory conditions. Apple bark was sprayed with conidial suspensions of both fungi, at a standard infective conidial concentration of 107 conidia/ml. The persistence, or survival, of the conidia on apple bark was measured using codling moth larvae (CM) (Cydia pomonella) and females of woolly apple aphid (WAA) (Eriosoma lanigerum) as indicator species. The results showed that conidia of M. pinghaense can induce mortality of insect pests through contact with an EPF-treated substrate, with mortality of 39% to 82% for WAA over a period of 10 days post application, and with mortality of 3% to 68% for CM over a period of 7 days, after application to apple bark. Further evaluation showed that the conidia of M. pinghaense persisted longer on apple bark, up to 63%, than did M. brunneum, up to 11%, three weeks post application of the conidial suspensions. The study provides insights into the potential persistence of fungal isolates on apple bark over time post application. Further evaluation of the persistence of the isolates on apple bark under both glasshouse and field conditions should be conducted.
... For example, immune processes such as broad-spectrum melanization response and phagocytosis are performed optimally in mosquitoes (Anopheles stephensi) at 18°Celsius [22], below and above which mosquitoes may be more vulnerable to infections. In fact, there are species of parasites that are 'cold-active', specializing on hosts enduring wintering temperatures, such as the fish bacterium Flavobacterium psychrophilum [23] or those exclusively occupying habitats of overwintering insects [24]. Seasonal variability in transmission patterns have often been associated with a high propensity for disease outbreaks [17,25], suggesting that parasites have evolved effective phenotypes to not just endure but thrive through harsh seasonal conditions. ...
The persistence of parasite populations through harsh seasonal bouts is often critical to circannual disease outbreaks. Parasites have a diverse repertoire of phenotypes for persistence, ranging from transitioning to a different life stage better suited to within-host dormancy to utilizing weather-hardy structures external to hosts. While these adaptive traits allow parasite species to survive through harsh seasons, it is often at survival rates that threaten population persistence. We argue that these periods of parasite (and vector) population busts could be ideal targets for disease intervention. As climate change portends abbreviated host dormancy and extended transmission periods in many host–parasite systems, it is essential to identify novel pathways to shore up current disease-intervention strategies.
... Soil surveys from different sites suggest that in agriculture fields soil in temperate region, Metarhizium spp. are the most abundant entomopathogens fungal (Bidochka et al., 1998). Bischoff Usually, identification of Metarhizium has been done by observing its morphology on culture media, target host bioassay and associated structures and examination of spores under microscope which resulted in recognition of two species initially: M. flavoviride and M. anisopliae. ...
The entomopathogenic fungi have been isolated from insects and used in fighting against number of pests by acting as biocontrol agent. They are safe for plants, animals and the environment as compared to conventional pesticides. Moreover, the entomopathogenic fungi genetic variability is thought as one of the chief control parameters for insects. In this study, inter transcribed spacers (ITS) region of M. anisopilae that has been implemented to play diverse role in armoring M. anisopilae against various pest was characterized using conventional polymerase chain reaction and sequencing. For this purpose, the genomic DNA of M. anisopilae was extracted and a 700bp fragment of ribosomal DNA (r-DNA) that was characterized as ITS was amplified using ITS specific primers. The results indicated that inter transcribed spacers (ITS) region is indispensable for Metarhizium anisopliae mediated biological control of insects. Further in-depth studies are required to evaluate factors such as the genetic variability and genetic diversity that are responsible for the conferring pesticidal effects in other fungal species.
... Besides, if applied as biopesticides, these strains can overcome environmental stress and adapt better to environmental conditions [24,29]. Indeed, several studies have reported that the tolerance of entomopathogenic fungi to climatic conditions is strongly related to its natural habitat [24,30,31]. ...
Two isolates of the entomopathogenic fungi (EPF) Beauveria bassiana (Hypocreales: Cordycipitaceae), an isolate of Aspergillus flavus (Eurotiales: Trichocomaceae), of Verticillium sp. (Glomerellales: Plectosphaerellaceae) and of Aschersonia sp. (Hypocreales: Clavicipitaceae) were evaluated for their pathogenicity against the Mediterranean fruit fly Ceratitis capitata (Diptera: Tephritidae) pupae and adults under laboratory conditions, using four different concentrations. Pathogenicity towards pupae and adults was tested via spraying and body contact bioassays respectively. Average mortality of treated individuals ranged from 60 to 100% for pupae and from 39 to 100% for adults depending on the fungal isolates and concentrations. The highest mortality levels were observed for individuals treated by Verticillium sp., A. flavus and Aschersonia sp., while the B. bassiana isolates were the less effective against both adult and pupae. Estimated lethal concentrations 90 ranged from 3x105 to 3.8 x 107 conidia/ml for adults and from 6.58 x 103 to 2.5 x 105 conidia/ml for pupae with lower values calculated for A. flavus, Verticillium sp. and Aschersonia sp. Mean lethal times 90 were less than 79h for C. capitata adults and ranged from 94 to 273 hours for pupae according to the fungal isolates. Microscopic observation of treated pupae showed a mycelium growth on the bodies of death individuals, while visible signs of mycosis are less observed for adults. Results of these experiments demonstrated that native EPF isolates could be a promising biocontrol agent to manage safely C. capitata and might be used against pupae by soil application or against adults by cover or bait sprays.
... are considered the most common cosmopolitan EMPF, parasitizing a wide range of insect species [10,13,43]. Both B. bassiana and M. anisopliae are among the most famous and globally distributed EMPF, revealing significant genetic diversification [44,45]. The versatile lifestyle of those two important EMPFs, wide host range and persistence in harsh habitats where preferred hosts (insects or plants) are temporarily unavailable, supported potential roles and values as microbial-based applications in integrated pest management strategies [45,46]. ...
The compound negative impact of insect pests attacking agricultural ecosystems includes (i) direct yield losses from damaged crops, (ii) the economic cost of the attempt to prevent these losses and (iii) the negative short- and long-term hazard effects of chemical pesticides on human and environmental health. Entomopathogenic fungi (EMPF) are a group of microorganisms that represent the natural enemies of a number of crop pests, presenting an opportunity to harness their evolutionary fine-tuned relationship with their insect hosts as biocontrol agents in integrated pest management programs. The aim of this study was to establish an indigenous EMPF collection via the Galleria mellonella (greater wax moth) entrapment method from the soils of Nile Delta, Egypt. Obtained insect associated fungal isolates were bio-assayed for pathogenicity against the serious pest Spodoptera litura and Tenebrio molitor, and the seven outperforming isolates were selected for molecular identification and thermotolerance assay. Based on ITS sequence analysis and phylogeny, selected isolates were identified as Beauveria bassiana (four isolates), Metarhizium anisopliae (two isolates) and one isolate of Cordyceps javanica. The obtained results demonstrated (i) the efficacy of using insect baiting coupled with molecular identification and pathogenicity screening to isolate EMPF to control insect pests, and (ii) the availability of indigenous virulent EMPF in Nile Delta’s soil, which can be exploited for the development of sustainable crop protection strategies.
... Besides, if applied as biopesticides, these strains can overcome environmental stress and adapt better to environmental conditions [24,29]. Indeed, several studies have reported that the tolerance of entomopathogenic fungi to climatic conditions is strongly related to its natural habitat [24,30,31]. ...
Indole acetic acid (IAA) and salicylic acid (SA) are plant bioregulators that stimulate the desired growth and quality response in crops. This study examined the impacts of IAA or SA seed pre-treatment on phytochemical constituents and antioxidants potential in three genotypes of tomato plant. The results indicated that IAA and or SA treatments increased height of the three genotypes of tomato significantly (P ≤ 0.05) when compared with the control group. Lycopene, total flavonoid and phenolic contents of genotypes F2 cobra and panther 17 F1 treated with 40, 80, and 120 mg/L concentrations of IAA, respectively increased significantly as compared to the control group. Furthermore, IAA and or SA significantly increased H2O2 scavenging activity of F1 KIARA by 5.0% compared to the control (0.2%). Genotype F1 KIARA treated with IAA and or SA (80 and 120 mg/L) had a significant increase in DPPH scavenging activity by 55.0% and 53.0% respectively, relative to control group (11%). The Fe2+-chelating activity of IAA-treated (80 mg/L) F1 KIARA and F2 COBRA increased by 56.0% and 17.0%, respectively compared to the control. The synergistic effect of IAA and SA showed a significant effect on phytochemical constituents and antioxidant potential than individual treatment. The results showed that IAA application or in combination with SA could be used as an alternative bio-stimulant to improve the quality of tomato.
... Entomopathogenic fungi parasitise ticks and insects and are widely distributed in soils (Bidochka and Kasperski 1998;Keller et al. 2003;Meyling and Eilenber 2007). Promising results have been reported on the potential of the entomopathogenic fungi, mainly Metarhizium anisopliae (Hypocreales: Clavicipitaceae) and Beauveria bassiana (Hypocreales: Cordycipitaceae), as biocontrol agents of ticks (Lubeck et al. 2008;Fernandes et al. 2011Fernandes et al. , 2012Campos et al. 2010;Camargo et al. 2012;Ren et al. 2012;Ma et al. 2013;Munteanu et al. 2014). ...
Beauveria bassiana (Hypocreales: Cordycipitaceae) is an entomopathogenic fungus that has shown promising results as a biocontrol agent of ticks. Locally isolated B. bassiana are better acclimatised to the natural conditions of their geographical origin; therefore, they are essential in developing effective biocontrol agents for ticks. The current study aimed to isolate native strains of B. bassiana that are pathogenic to Rhipicephalus microplus ticks. The virulence of the isolates was tested against R. microplus larvae using a formulation containing 15% avocado oil, 0.05% adjuvant and 10⁸ conidia mL⁻¹. The two best strains were further evaluated for various biological parameters on adult engorged female ticks. Breakthru® or Ballista® (adjuvant) was mixed with the formulation to compare their effect on the isolates' virulence. In total 61 entomopathogenic fungi were isolated from the 360 greater wax moth larvae, Galleria mellonella (Lepidoptera: Pyralidae) used. The virulence test identified Bb-40 and Bb-41 to be the most virulent isolates against R. microplus larvae with mortalities of 91 and 93% and LT50 values of 5.8 and 6.2 days, respectively. Compared to the control, both strains significantly affected all the measured biological parameters. The type of adjuvant also considerably affected the susceptibility of ticks to the fungi. In conclusion, the two isolates combined with adjuvants can be used as a biocontrol agent to control R. microplus.
... A total of 249 isolates were recovered from soils of three Lebanese cedar forests using different isolation methods. Similar occurrences have been previously reported by Keller et al. [17], Rath et al. [42], Bidochka and Kasperski [43], Pérez-González et al. [44], Niemczyk et al. [45], and Sánchez-Peña et al. [46]. Beauveria isolates were recovered from 25% of the soil samples. ...
The cedar forests of Lebanon have been threatened by the outbreak caused by climate change of a web-spinning sawfly, Cephalcia tannourinensis (Hymenoptera: Pamphiliidae), which negatively impacted the survival of one of the oldest tree species on earth. In this study, we investigated the occurrence of naturally soil-inhabiting entomopathogenic fungi for their role in containing the massive outbreak of this insect. We used a combination of fungal bioexploration methods, including insect bait and selective media. Morphological features and multilocus phylogeny-based on Sanger sequencing of the transcripts encoding the translation elongation factor 1-alpha (TEF-α), RNA polymerase II second largest subunit (RBP2), and the nuclear intergenic region (Bloc) were used for species identification. The occurrence rate of entomopathogenic fungi (EPF) varied with location, soil structure, forest structure, and isolation method. From 15 soil samples positive for fungal occurrence, a total of 249 isolates was obtained from all locations using different isolation methods. The phylogenetic analysis confirmed the existence of two novel indigenous species: Beau-veria tannourinensis sp. nov. and Beauveria ehdenensis sp. nov. In conclusion, the present survey was successful (1) in optimizing the isolation methods for EPF, (2) investigating the natural occurrence of Beauveria spp. in outbreak areas of C. tannourinensis, and (3) in characterizing the presence of new Beauveria species in Lebanese cedar forest soil.
... The soil environment is usually the conventional isolation site for hypocrealean entomopathogenic fungi (Keller and Zimmerman, 1989; Hajek, 1997 ( , and several species can be found in both cultivated and more natural habitats (Vanninen, 1996; Klingen et al., 2002). Bidochka et al. (1998) found Beauveria. bassiana to be affiliated with shaded and uncultivated habitats (i.e., forests) and B. bassiana also occurred frequently in hedgerow soils at a Danish locality (Meyling and Eilenberg, 2006 Finney, (1964). ...
Chemical control for pests has been a serious concern for human and animal health; therefore this study was undertaken to screening of entemopathogenic fungi that are effective against against Greater wax moth Galleria mellonella. entemopathogenic fungi were isolated from different agricultural soil samples by plate dilution and baiting techniques. The crude extract of isolated fungi were screened against G. mellonella. Applied different fungal crude extracts of iolates achieved variable results on both larval and adult mortality percentages. The effect of crude extracts of Beauveria bassiana (Siwa isolate), Aspergillus tamarii, Fusarium solani, F. oxysporum, F. chlamydosporum and B. bassiana (El-Farafra isolate) giving total death percentages (82.48, 45.36, 37.12, 49.48, 53.6 and 74.22, respectively) to G. mellonella larvae comparing with the control treatment 0%. The results exhibited significant effects of B. bassiana (El-Farafra and Siwa Oasis isolates) against G. mellonella (larval and pupal weights). The % of larvae death increased with increasing the concentration of crude extract of B. bassiana (El-Farafra and Siwa isolates). Also pupal death percentage of G. mellonella increased while adult emergence decreased with increasing concentration of crude extract of El-Farafra and Siwa isolates of B. bassiana. On the other hand, crude extract of B. bassiana (El-Farafra isolate) was more active than B. bassiana (Siwa isolate) at high concentration (50 mg/ 0.5ml) while at other concentration crude extract of B. bassiana (Siwa isolate) was more active than B. bassiana (El-Farafra isolate). At the same time, different fractions of B. bassiana (Siwa isolate) extract were tested to determine the active metabolite. The bioactive compound was separated and identified as Beauvericin with using Thin layer chromatography, Fourier Transform Infrared (FT-IR) and analytical X ray.
... Entomopathogenic nematodes (EPNs) and fungi (EPF) are natural inhabitants of most terrestrial ecosystems, including natural and agricultural areas (Bidochka et al., 1998;Adams et al., 2006;Meyling and Eilenberg, 2006). Since they are considered excellent biological control agents of arthropod pests (Faria and Wraight, 2007;Roy et al., 2010;Lacey et al., 2015), many commercial products based on them are also available to implement in IPM programs and organic production (Campos-Herrera, 2015;Lacey et al., 2015). ...
Earthworms are ecological engineers that can contribute to the displacement of biological control agents such as the entomopathogenic nematodes (EPNs) and fungi (EPF). However, a previous study showed that the presence of cutaneous excreta (CEx) and feeding behavior of the earthworm species Eisenia fetida (Haplotaxida: Lumbricidae) compromise the biocontrol efficacy of certain EPN species by reducing, for example, their reproductive capability. Whether this phenomenon is a general pattern for the interaction of earthworms-entomopathogens is still unknown. We hypothesized that diverse earthworm species might differentially affect EPN and EPF infectivity and reproductive capability. Here we investigated the interaction of different earthworm species (Eisenia fetida, Lumbricus terrestris, and Perionyx excavatus) (Haplotaxida) and EPN species (Steinernema feltiae, S. riojaense, and Heterorhabditis bacteriophora) (Rhabditida) or EPF species (Beauveria bassiana and Metarhizium anisopliae) (Hypocreales), in two independent experiments. First, we evaluated the application of each entomopathogen combined with earthworms or their CEx in autoclaved soil. Hereafter, we studied the impact of the earthworms' CEx on entomopathogens applied at two different concentrations in autoclaved sand. Overall, we found that the effect of earthworms on entomopathogens was species-specific. For example, E. fetida reduced the virulence of S. feltiae, resulted in neutral effects for S. riojaense, and increased H. bacteriophora virulence. However, the earthworm P. excavates increased the virulence of S. feltiae, reduced the activity of H. bacteriophora, at least at specific timings, while S. riojaense remained unaffected. Finally, none of the EPN species were affected by the presence of L. terrestris. Also, the exposure to earthworm CEx resulted in a positive, negative or neutral effect on the virulence and reproduction capability depending on the earthworm-EPN species interaction. Concerning EPF, the impact of earthworms was also differential among species. Thus, E. fetida was detrimental to M. anisopliae and B. bassiana after eight days post-exposure, whereas Lumbricus terrestris resulted only detrimental to B. bassiana. In addition, most of the CEx treatments of both earthworm species decreased B. bassiana virulence and growth. However, the EPF M. anisopliae was unaffected when exposed to L. terrestris CEx, while the exposure to E. fetida CEx produced contrasting results. We conclude that earthworms and their CEx can have positive, deleterious, or neutral impacts on entomopathogens that often coinhabit soils, and that we must consider the species specificity of these interactions for mutual uses in biological control programs. Additional studies are needed to verify these interactions under natural conditions.
... and Lecanicillium spp. M. anisopliae is generally more resistant to agricultural disturbances, and numerous studies have reported that it is significantly more prevalent in cultivated areas than in natural habitats [8,56,63,64]. The current study shows that, especially in autumn, in the case of soils from the deciduous and mixed forests in Chodów, the CFU density of the fungi Metarhizium spp. ...
This study aims to determine the species composition and density of colony-forming units (CFU) of entomopathogenic fungi (EPF) in leaf litter at different depths of the top layer of forest soils depending on the type of forest (coniferous, deciduous and mixed forest), and the date of sampling (spring, autumn). In each type of forest, leaf litter and soil were collected using a soil stick from four depths of soil: 0–5, 5–10, 10–15 and 15–20 cm. Entomopathogenic fungi were isolated by a soil or litter dilution plating method on a selective medium. Four fungal genera were found: Beauveria spp., Cordyceps spp., Metarhizium spp., and Lecanicillium spp. The density of EPF was usually higher in leaf litter than in the layers of soil below, and the most frequently isolated species from both environments were Beauveria spp. among soil samples from all forest types; Beauveria spp. were most abundant in the top layer (0–5 cm), and their density of CFUs gradually decreased deeper into the soil profile.
... Hence, it was not surprising that a higher C/N, resulting from a high OM, significantly increased soil fusaria in Portuguese vineyards [28]. Bidochka et al. also noticed that Metarhizium prefers agricultural and cultivated habitats that tend to have lower OM when compared with forest or semi-natural habitats [59]. We observed that M. robertsii could only be isolated from tilled vineyard soils and not from untilled hedgerows dominated by oaks and pine trees. ...
Entomopathogenic fungi (EPF) contribute to different ecosystem services. However, factors affecting their natural occurrences in soil remain poorly understood. In a previous study, 81 soil samples were subjected to insect baiting using Galleria mellonella and Tenebrio molitor to isolate EPF from Portuguese vine farms. Here, soils yielding any of the four common EPF, i.e., Beauveria bassiana, Purpureocillium lilacinum, Metarhizium robertsii, and Clonostachys rosea f. rosea, were correlated with their chemical properties. Beauveria bassiana was negatively affected by higher available P (p = 0.02), exchangeable K-ions (p = 0.016) and positively affected by higher soil pH_H2O (p = 0.021). High exchangeable K-ions inhibited P. lilacinum (p = 0.011) and promoted C. rosea f. rosea (p = 0.03). Moreover, high available K also suppressed P. lilacinum (p = 0.027). Metarhizium robertsii was inhibited by higher organic matter content (p = 0.009), higher C:N (p = 0.017), total N (p = 0.007), and exchangeable Mg-ions (p = 0.026), and promoted by higher exchangeable Na-ions (p = 0.003). Nonetheless, mean comparisons and principal component analysis suggested that higher soil pH and exchangeable Ca-ions have contrasting effects on EPF occurrences, as they promote B. bassiana and inhibit M. robertsii. Herbicides did not seem to affect EPF presence. Overall, this study is among the first reports on the effects of soil chemistry on EPF other than Metarhizium, and will facilitate biological pest management approaches.
... Fungal pathogens particularly Beauveria bassiana, these toxins have diverse effects on various insect tissues. The white muscardine fungus Beauveria bassiana occurs naturally in soil (Bidochka et al., 1998). Under favourable conditions, it sporulates extensively on the cadaver to facilitate further infection in the host population (Chandler et al., 2000). ...
The present investigation entitled “Mass Production of entomopathogenic fungai Beauveria bassiana (Metsch.) on liquid and solid media” was carried out at Bio Control Laboratory, Department of Entomology, Sardar Vallabhbhai Patel University of Agriculture and Technology, Meerut during 2018-19. In all there were eight treatments including control replicated thrice in a randomized block design. The results obtained in the study are summarized. The effect of different substrates for the mass production of Beauveria bassiana spore/ml was significantly higher recorded. Data recorded on 7, 14, 21, 28, 35 after the day after inoculation of various treatments in the, T10 Savoured dextrose broth (SDB), was the best treatment by bringing down the B. Bassiana production up to (49.48) spore/ml in liquid medium during the 2018-19 years. The other treatments in order of spore producing was with T11 Potato dextrose broth (PDB) (38.52), in liquid medium and solid medium in the treatment and T8 Cowpea Vigna unguiculata + Molasses + 1% YE + 1.0 g Dextrose (28.73), followed by with T7 Black gram Vigna mungo + Molasses + 1% YE + 1.0 g Dextrose (27.52 spore/ml, T5 Cowpea Vigna unguiculata + Molasses + 1% YE (17.53 spore/ml), T4 Black gram Vigna mungo + Molasses + 1% YE (14.87 spore/ml), T2 Cowpea Vigna unguiculata + Molasses (10.50 spore/ml), T1 Black gram Vigna mungo + Molasses (8.35 spore/ml), T9 Gram Cicer aeritinum + Molasses + 1% YE + 1.0 g Dextrose (3.92 spore/ml), T6 Gram Cicer aeritinum + Molasses + 1% YE (2.85 spore/ml) and T3 Gram Cicer aeritinum + Molasses respectively.
... The high occurrence of M. anisopliae in commercially cultivated habitats is due to M. anisopliae conidia persisting for fairly long periods without infecting the hosts, whereas the lack of susceptible hosts in commercial heavily cultivated orchards minimises the persistence of B. bassiana in the soils (Fargues & Robert 1985;Vänninen 1996). Metarhizium anisopliae is more tolerant to synthetic pesticides than is B. bassiana, leading to the lack of insect hosts, together with the low tolerance of pesticides, adversely reducing the competitiveness of B. bassiana in commercial orchards (Bidochka et al. 1998). ...
The banded fruit weevil (BFW), Phlyctinus callosus (Coleoptera: Curculionidae), is a major
indigenous pest of deciduous fruits and grapevine in the Western Cape province of South
Africa. Entomopathogens are effective in controlling soil-borne and above-ground stages of insect pests. Soil samples were collected from deciduous fruit orchards and vineyards in the Western Cape, baited with mealworms to isolate entomopathogenic nematodes (EPNs) and entomopathogenic fungi (EPF), which were identified using molecular techniques and assessed for their potential as biocontrol agents of BFW adults. A correlation analysis was performed to determine the effect of soil parameters on the presence of the entomopathogens. EPNs were trapped in 12 (17 %) samples, while Heterorhabditis bacteriophora and Heterorhabditis safricana were the only two species isolated. EPF were isolated from 26 (37 %) samples baited, with 14 fungal isolates identified as Beauveria bassiana (Cordycipitaceae) and 12 identified as Metarhizium anisopliae (Clavicipitaceae) complex. Heterorhabditis bacteriophora (53 %) gave significantly higher (P < 0.05) control of adult BFW than H. safricana (37 %). Metarhizium anisopliae (79 %) gave significantly higher (P < 0.05) control of BFW adults than B. bassiana (63 %). Organic matter, magnesium and phosphorus had a negative relationship
with the occurrence of EPNs. A negative relationship was also reported between the
occurrence of EPF, and organic matter and potassium. The results indicated that soils from the deciduous fruit orchards and vineyards from the Western Cape contain both EPNs and EPF with potential to be used in an integrated pest management system against soil-borne and above-ground stages of BFW.
Key words: biocontrol, deciduous fruit, entomopathogenic fungi, entomopathogenic nematodes, soil-dwelling insects.
... Vuill. prefers natural sites and soil from orchards (Miętkiewski et al. 1991;Bidochka et al. 1998;Klingen et al. 2002;Sun et al. 2008;Jarmuł-Pietraszczyk et al. 2011;Medo & Cagáň 2011;Kepler et al. 2015;Steinwender et al. 2015). The research in north-western Poland has led to similar conclusions: the occurrence of B. bassiana has rarely been observed in comparison with other entomopathogenic taxa. ...
In 2016-2018, in north-western Poland, field studies were carried out on the coexistence of various taxonomic groups, such as soil nematodes and fungi, including beneficial species that comprise the environment’s natural resistance to pests in agrocenoses. The research aimed to find a connection between select biotic and abiotic factors in the chosen crops which could have practical applications in plant protection. Entomopathogenic nematodes Steinernema feltiae Filipiev, 1934 and entomopathogenic fungi Cordyceps fumosorosea and Metarhizium anisopliae (Metschn.) Sorokin were found to be present in all studied agrocenoses; however, they showed clear preferences for some types of crops or soil. The research shows that the effectiveness of the biological methods of plant protection depends on the selection of the right biopreparations, which strengthen the local populations of the beneficial organisms present in specific agriculture areas.
... B. bassiana exhibits more dominance and viability than M. anisopliae, perhaps be due to some environmental factors; B. bassiana can infect many species of insects and can grow on artificial media or some kinds of soil [29]. M. anisopliae conidia were able to survive in the soil longer than B. bassiana, because it seems that the latter was more sensitive to the soil microbiota [30]. These host insects are found in large masses in the terroirs. ...
Fungi are eukaryotic microorganisms with many forms and certain demands about the soil they colonize, which reveal the conditions that prevail therein. Although they can often kill pests without damaging plants or humans, they are not widely used as pesticides as they are not easy to handle and require much time before they act. Nevertheless, insects can be used as baits to trap these entomopathogenic fungi, giving information about their distribution within the terroir. The purpose of this study was to investigate the soil distribution of entomopathogenic fungi species in soil samples from two vine soil terroirs. Nine fungi were identified in total, but M. anisopliae and B. bassiana showed the greatest frequency, which was expressed by difference in adult bait mortality among species. These fungi had not been previously documented in vine terroirs.
... We believe that low infection rate was due to an overly short exposure of larvae to EPF spores, as last-instar larvae pupate soon after emerging from fallen fruit (Weems et al. 2001). In contrast, several studies reported high infection percentages using G. mellonella larvae as bait-insects (Bidochka et al. 1998, Keller et al. 2003, Masoudi et al. 2018). Nevertheless, comparisons should be taken with caution, as A. ludens larvae may be less susceptible to EPF infection compared to G. melonella larvae. ...
The Mexican fruit fly, Anastrepha ludens Loew, is a significant pest in mango and citrus production areas of Mexico. In this study, we evaluated the effects of some geographic characteristics, rainfall period, soil micro-environmental, and soil coverage variables on the occurrence of entomopathogenic fungi (EPF) associated with A. ludens larvae in soils of mango, grapefruit and mixed crops in central Veracruz state, Mexico. EPF isolates were characterized morphologically and identified by sequence analysis of elongation factor (EF1-1018F, EF1-1620R). We recorded four species of EPF (Metarhizium robertsii J.F. Bisch, S.A. Rehner & Humber [Hypocreales: Cordycipitaceae], M. brunneum Petch [Hypocreales: Cordycipitaceae], M. pinghaense Q.T. Chen & H.L. Guo [Hypocreales: Cordycipitaceae], and Beauveria bassiana (Balsamo) Vuillemin [Hypocreales: Cordycipitaceae]), of which Metarhizium robertsii was the most abundant and the most virulent. Also, we found that rainfall period, organic matter, coverage of herbs and forbs, and calcium levels modulated EPF occurrence. We estimated lethal concentrations for A. ludens larvae of the four most promising isolates, V3-123, V3-160, V1-332, and V3-369. Our results suggest that M. robertsii obtained from agricultural soils holds potential as a biological control agent for A. ludens.
... (1 = Zhang Shu Liang (ZSL); 2 = Jiu Zhen Feng (JZF); 3 = Yu Xi Zhen (YXZ); 4 = Long Ding Shan (LDS); 5 = San Hui (SH); 6 = Yi Yang Cun (YYC); 7 = Nan Yue Cun (NYC); 8 = Xia Su Cun (XSC); 9 = Zhang Hui Shan (ZHS); 10 = Jiu Long Cun (JLC); 11 = Qing Long Cun (QLC); 12 = Jian An (JA); 13 = Kia Su Cun (KSC); 14 = Wan'An Xiang (WAX); 15 = Shui Mo Ba (SMB); 16 = Ya Jiang (YJ); 17 = Xin Long (XL); 18 = Ling Ton (LT); 19 = Xia Bai Sang Cun (XBSC). regional community surveys conducted in North and South America (Bidochka et al., 1998;Bidochka et al., 2001;Bidochka et al., 2005;Inglis et al., 2008;Wyrebek et al., 2011;Lopes et al., 2013a;Lopes et al., 2013b;Lopes et al., 2014;Kepler et al., 2015;Rezende et al., 2015;Inglis et al., 2018), Europe (Vanninen, 1996;Meyling and Eilenberg, 2007;Meyling et al., 2011;Steinwender et al., 2014;Keyser et al., 2015;Steinwender et al., 2015) and Asia (Kawakami and Naka, 1979;Nishi et al., 2011;Sevim et al., 2012;Luan et al., 2013;Zhang et al., 2016;Luangsa-ard et al., 2017;Nishi et al., 2017a;Nishi et al., 2017b;Masoudi et al., 2018). The presence of one indigenous Metarhizium lineage to be more common species has been an outcome of interest in these studies, and some of them showed that plant hosts could influence the Metarhizium abundances, suggesting that the association of Metarhizium species within the plant rhizosphere. ...
To understand the ecological roles and life history of the entomopathogenic fungi Metarhizium, its natural distribution must be known. The ability to recognize a limited species using robust regions of the genome to illustrate species boundaries diagnostically and phylogenetically is a crucial step. To investigate the phylogenetic relationship within Chinese Metarhizium isolates, an extensive sampling survey was conducted at 19 geographically separated locations in diverse forest regions of Sichuan Province. Isolation was accomplished using the insect susceptible-bait method with Tenebrio molitor larvae (Coleoptera, Tenebrionidae). Of the 173 Metarhizium isolates obtained, the maximum likelihood of both nuclear intergenic sequence markers Mz_IGS3 and Mz_FG543 revealed that 75 belonged to M. pingshaense, 44 to M. robertsii, 10 to M. brunneum, 4 to M. guizhouense, 3 to the M. flavoviride species complex (M. bibionidarum) and 37 to a segregated, unknown Metarhizium cluster. M. pingshaense was the predominant Metarhizium spp. isolate, followed by M. robertsii. Further molecular characterization was performed using GCPSR-based multilocus (6796 bp segments composed of whole translation elongation factor-1 alpha 5' and 3'-TEF, β-tubulin, ITS, and two intergenic spacers) phylogenetic analyses to illustrate the unexplained Metarhizium clade with reference sequences. The results revealed this cluster is a sister to the M. lepidiotae clade in the M. anisopliae species complex and may limit the geographical distributions of distinct Metarhizium spp., which contrasts with the large-scale distribution of the PARB (M. pingshaense, M. anisopliae, M. robertsii and M. brunneum) clade. These results indicate this cluster possesses a different ecological distribution and/or dispersal ability, which could lead to novel communities and interactions.
Although the use of under-trellis plants as weed control (living mulch) in vineyards has been gaining popularity, its effects on soil quality and especially soil biology have not been well studied. Due to functional trait differences, plants may differ in how they compete with vines, and may also change abiotic and biotic soil properties. A living mulch trial was established in the semi-arid Okanagan valley of British Columbia comparing vine growth as well as soil abiotic and biotic outcomes for four living mulch treatments: buffalo grass (Bouteloua dactyloides), Chewing's fescue (Festuca rubra ssp. com-mutata), birdsfoot trefoil (Lotus corniculatus), and shep-herd's purse (Capsella bursa-pastoris) with two industry standards: herbicide and cultivation. After two seasons, strong vine growth responses were seen that depended on living mulch identity, e.g., reduction in leaf N status with grasses, reduction in leaf water potential with the legume, birdsfoot trefoil. These effects were related to plant-induced changes to soil C:N ratio and soil moisture. Although treatments did not change abundance of the measured fungal guilds in bulk soil, abundance of ar-buscular mycorrhizal fungi in vine roots was lowest with birdsfoot trefoil as living mulch. This study may help growers to select living mulch species appropriate for the soil conditions and resource availability of their site. K e y w o r d s : cover crops; living mulch; vineyards; competition; soil properties; arbuscular mycorrhizal fungi; ento-mopathogenic fungi; soil borne pathogens.
The natural occurrence of entomopathogenic fungi (EPF) was investigated along the Ticino River (Ticino River Natural Park, Novara Province, Piedmont, Italy), at the center of the area of the first settlement of the invasive alien pest Popillia japonica. Using Zimmermann's "Galleria bait method", EPF were successfully isolated from 83 out of 155 soil samples from different habitats (perennial, cultivated, or uncultivated meadows, woodlands, and riverbanks). Sequencing of the 5' end of the Translation Elongation Factor 1 alfa (5'-TEF) region allowed the assignment of 94% of the isolates to Metarhizium spp., while 8% and 7% were assigned to Beauveria spp. and Paecilomyces spp., respectively. Four Metarhizium species were identified: Metarhizium robertsii was the most common one (61.5% of the isolates), followed by M. brunneum (24.4%), M. lepidiotae (9%), and M. guizhouense (5.1%). Microsatellite marker analysis of the Metarhizium isolates revealed the presence of 27 different genotypes, i.e., 10 genotypes among M. robertsii, 8 among M. brunneum, 5 among M. lepidiotae, and 4 among M. guizhouense. Metarhizium brunneum appeared to be associated with woodlands and more acid soils, while the other species showed no clear association with a particular habitat. Laboratory virulence tests against P. japonica 3rd instar larvae allowed the identification of one M. robertsii isolate that showed efficacy as high as 80.3%. The importance of this kind of study in the frame of eco-friendly microbiological control is discussed.
This volume is a compilation of reviews on the industrial usage of soil microorganisms. The contents include 15 brief reviews on different soil microbe assisted industrial processes. Readers will be updated about recent applications of soil bacteria, fungi and algae in sectors such as agriculture, biotechnology, environmental management.
The reviews also cover special topics like sustainable agriculture, biodiversity, ecology, and intellectual property rights of patented strains, giving a broad perspective on industrial applications of soil microbes. The text is easy to understand for readers of all levels, with references provided for the benefit of advanced readers.
The fungus genus Metarhizium (Family: Clavicipitaceae, Order: Hypocreales) is an entomopathogenic group of pleomorphic species that have been used historically as biocontrol agents. They are soil inhabitants and rhizosphere associates that show a symbiotic relationship with plants resulting in increased plant growth and development. Thus application of Metarhizium in plant systems protects plants from insect herbivoures and helps plant in nutrient acquisition. However, inconsistent and variable results were observed in field trial limits the application of Metarhizium in large-scale application as biological control agents. A limiting factor in improving Metarhizium species as bio-control agents is lack of the research on evolution and functional ecology of Metarhizium species.
This study isolated Metarhizium strains from agricultural fields, grasslands and forests soils in three locations in Queensland, Australia to identify the naturally occurring species and their phylogenetic relationship. The multi-locus analysis of concatenated sequence data sets of MzIGS3 and 5’-TEF resolved the taxonomic position of 164 Metarhizium strains. Five taxonomic groups, M. robertsii, M. pinghaense and M. anisopliae as well as two strongly supported clades of taxonomically indeterminate groups were resolved. Phylogenetic and population genetic analyses indicated that the two indeterminate clades represented two new Metarhizium species. Moderate genetic differences and gene flow were observed between the Metarhizium population from different locations and ecotypes.
Factors affecting the diversity of Metarhizium species in soils of different ecotypes and locations were analysed using multivariate and univariate analyses. The distribution of Metarhizium species varied with location and ecotype. M. anisopliae and M. robertsii isolates were predominantly recoverd from laegume and forest soils and associated with high nitrogen and carbon contents in soil. Isolates of M. indet.1 clade were predominat in maize and grassland soils and associated with low nitrogen and carbon. A minor soil element Zr was positively associated with M. anisopliae, M. robertsii and M. indet.1 isoaltes.
The reconstructed phylogenetic relationship, population and ecological analyses of Metarhizium isolates from soil in legume and maize fields showed different taxonomic groups that were associated with legume and maize ecotypes. Six isolates associated with legume and six isolates associated with maize field were evaluated for colonisation in pea and maize systems in the laboratory. The results showed plant systems and fungal isolates were significantly different in root colonisation and higerher colonisations were occurred in pea than maize irrespective of crop from which isolated. The results indicate that the host plant influence both the Metarhizium species diversity in soil and colonisation of Metarhizium in plant root.
To determine the effect of plant strigolactone on endophytic association between plant and fungus Metarhizium anisopliae, spore germination and root colonisation of the M. anisopliae were estimated on wild type pea (Pisum sativum L. cv Torsdag) and strigolactone pea mutants, rms 5-3: strigolactone deficient and rms 4-1: strigolactone overproducing mutants. The results showed that the strigolactone increases both spore germination and colonisation by Metarhizium in early stage in plant rhizosphere
These research findings could be useful for Metarhizium species selection or introduction of commercially available strains in certain soil habitats for biological control program and establishment of Metarhizium in plant roots in agricultural fields.
Plant viruses pose a serious threat to agricultural production and incur
enormous costs to growers each year, both directly, in the form of yield and quality
loss, and indirectly, in the forms of time and funds spent on scouting and disease
management. Virus diseases cause plants crops losses annually in average of US$
60 billion. Accordingly, viral diseases need to be controlled for the sustainable agriculture and in order to maintain the quality and abundance of food production. Moreover, recently agriculture suffered from different problems such as; the contentious
changes in climatic factors globally, increasing the numbers of pathogens per year
and appearance of anew pests. Unfortunately, chemical control has negative impact
on the environment and on human health as well in addition it creates an imbalance
in the microbial biodiversity, which may be unfavorable to the activity of the beneficial organisms and may lead to the development of pathogens-resistant strains. The
most important thing is that agricultural sustainability should be supported by ecofriendly approaches such as discovery of new biocontrol agents capable to control the
plant viral diseases. To achieve this was inevitable to use the plant growth-promoting
microbes as effective biocontrol agents against plant viruses will hold the greatest
promise and is considered a pillar of integrated viral diseases management. We argue
that the use of growth-promoting microbes will preserve sustainable agriculture as
well as a clean environment free from pollution, which will be benefiting for both
the farmer and the consumer. So far, there are no such pesticides at the local level,
while at the international level there may be one or two products. We succeeded to
control some viruses infect potato by using the filtrates of seven Bacillus spp. mixed
with nanoclay, but the product is still under research and development.
Banana rust thrips, Chaetanaphothrips signipennis, are devastating insect pests of banana crops worldwide. The entomopathogenic fungi are naturally occurring microbes known to infect a variety of thrips species, but few studies have investigated the potential for tropical thrips control using fungal entomopathogens, and there are no commercial entomopathogenic products for C. signipennis or similar pests in Australia. Here, we investigated the occurrence of fungal entomopathogenic strains on banana farms in tropical Queensland, Australia. We sampled soil from five environmentally managed farms, and in the corresponding natural hedgerow adjacent to each farm, cultured naturally occurring endemic fungal isolates and evaluated their efficacy in laboratory, cage and field trials against C. signipennis. Entomopathogens identified through next-generation sequencing of soil and soil baiting were predominantly Metarhizium strains. Three Metarhizium strains comprising two species, M. lepidiote and M. guizhouense, were lab cultured and evaluated as potential controls against C. signipennis. All strains demonstrated significantly increased C. signipennis mortality in lab trials, with M. lepidiote providing the best control in the cage trials and greatest growth in the lab, so this strain was evaluated in the field trial. A single application of Metarhizium lepidiote reduced thrips damage enough below marketable limits for all treated banana bunches, while all untreated bunches were unmarketable. This isolate shows promise for development of a commercial strain against C. signipennis and may be useful in environmentally managed farming systems.
In this study, 22 different fungal isolates associated with naturally dead insects of order Hemiptera including Bemisia tabaci, Aphis gossypii and Phenacoccus solenopsis were isolated from three different agroecological zones namely hot arid, cotton and central mixed zone. Fungal species were characterized morphologically on the basis of colony color, shape and spore structures through using different dichotomous keys. As a result fungi belonging to different species of Aspergillus, Acremonium, Beauveria, Cladosporium, Alternaria, Clonostachys, Penicillium, Trichoderma, Fusarium, Metarhizium and Verticillium were identified. All isolates of individual species were identical with respect to morphological differentiation. Principal component analysis (PCA) indicates strong correlation between Verticillium lecanii and Aspergillus fumigatus with respect to their isolation source (insect host). However, based on PCA, an uneven distribution of entomopathogenic fungi in different insect hosts is evident. Phylogenetic analysis revealed that Aspergillus fumigatus and A. nidulans are more closely related to different species of Penicillium, while Aspergillus oryzae and A. flavus formed separate clades, whereas different species of Alternaria, Cladosporium and Fusarium formed separate clades. Thus, the information generated will add to our understanding of the insect associated fungal communities for future development of potential biocontrol agents and their application as a vital component of sustainable agriculture.
We used the following new range of insect species as baits for trapping entomopathogenic fungi: Plodia interpunctella, Rhyzopertha dominica, Tribolium confusum, Trogoderma granarium, Ephestia kuehniella and Tenebrio molitor, which constitute important stored product pests. Soil samples were collected from random points in olive tree orchards in Western Greece using Geographical Information Systems (GIS) and sample point coordinates were located with the Global Positioning System (GPS). Entomopathogenic fungi were identified by sequencing the ITS4 and ITS5 regions of the genomic DNA. Among the isolated fungal species, Beauveria bassiana and Metarhizium anisopliae showed the highest frequency, at 33.8% and 25.4% respectively. They also caused the most infestations of R. dominica and T. confusum whose mortality reached 33-97% and 87-100% respectively. We have also isolated various other fungal taxa such as Aspergillus alliaceus, Aspergillus insuetus, Aspergillus sp., Apophysomyces ossiformis, Chaetomium acropullum, Chaetomium sp., Chaetomium globosum, Chaetomium truncatulum, Trichoderma gamsii and Purpureocillium lilacinum. Our study confirms that T. confusum and R. dominica may be further utilized as baits for entomopathogenic fungi.
The occurrence of entomopathogenic fungi was investigated in 160 soil samples collected from two different ecosystems (Natural and Cultivated) in Lattakia, Syria, using the Galleria bait method. Entomopathogenic fungi were found to occur in 75% of the studied soil samples, with positive samples yielding 63 fungal isolates, belonging to 18 species from 9 genera. Isolates from the genus Beauveria were the most frequent and abundant entomopathogenic species recovered, comprising 45% of the total number of isolates. There was a significant difference in the occurrence of entomopathogenic fungi between the two ecosystems (Natural ad Cultivated ones) (p<0.05). Using Koch's postulates, the mortality rate caused by the fungal isolates to Galleria larvae was found to range from 0 to 100%. Isolates of Beauveria, Metarhizium and Conidiobolus were the most virulent isolates recovered.
A previous manuscript (Lockwood 1993) questioned the introduction of exotic natural enemies for control of grasshoppers that affect rangeland and agricultural crops. This article presents some opposite viewpoints on the use of classical biological control, grasshopper biology, economic impact, management tactics, the speCific natural enemies either released or slated for release, environmental concerns, and the review of these programs before release. In many areas, full agreement is indicated with positions presented by Lockwood; however, major differences of opinion exist. We believe that there is no scientific basis for establishing the new terminology “neoclassical biological control,” so traditional terminology is retained. Data on the use of arthropods and pathogensin classical biological control (including use of exotic natural enemies for control of native pests) show that this approach to pest management has controlled important pest species, has been associated with few if any serious environmental problems, and is aviable technique that was endorsed by the National Academy of Sciences and others. Therefore, the notion that the introduction of exotic natural enemies is categorically inappropriate is not accepted, nor is the idea that increased federal regulation would necessarily improve natural enemy establishment, improve control success, or eliminate negative environmental side effects. Rather, it is felt that mandatory Environmental Assessments and Environmental Impact Statements would restrict implementation of classical biological control. The speCific programs questioned by Lockwood (1993) were based on significant biological information, were reviewed thoroughly, and hold potential to provide long-term mitigation of a severe economic pest problem while reducing environmental risk linked with widespread pesticide application.
The conidia of 2 entomogenous fungi, Beauveria bassiana and Metarhizium anisopliae, were applied to the chrysomelid beetle-attracting tubers of Ceratosanthes hilariana, cowpea (Vigna unguiculata) foliage and cover slips and held outdoors under 3 exposure conditions of sunlight, or in the laboratory at 27 and 4 deg C, to determine the stability of conidia for potential use as microbial control agents of chrysomelid pests of grain legumes in Brazil. Under each exposure condition of sunlight (i.e. full, partial or no protection from sunlight), conidia of B. bassiana survived best on the cucurbitaceous tubers, but the persistence of M. anisopliae conidia was more variable. In all cases for both fungi, exposure of conidia to full sunlight on all substrates was most detrimental to conidial stability; the half-life was generally 1-2 days and conidia were nonviable within 1 week of exposure to sunlight. In contrast, conidia protected from sunlight survived much longer, in some cases remaining highly viable for more than or equal to 3 weeks. The results indicated that B. bassiana conidia retained high stability on beetle-attracting tubers if protected from sunlight. The use of fungal-treated tubers as a bait for control of chrysomelid beetles in cowpea-growing regions of Brazil or other countries is of potential importance.
Larvae of the elm bark beetle, Scolytus scolytus, were inoculated with conidia of the entomogenous fungi Beauveria bassiana (two strains), Metarhizium anisopliae (two strains), and Paecilomyces farinosus (two strains) and incubated over a range of temperatures (2°, 6°, 10°, 15°, and 20°C). One strain each of B. bassiana and P. farinosus caused infection even at 2°C, whereas the two strains of M. anisopliae caused no infection below 10°C. Infection of adult beetles by B. bassiana (one strain) and M. anisopliae (one strain) was tested at 15°, 20°, and 25°C (B. bassiana) and at 15° and 20°C (M. anisopliae). Fungal infection occurred at all three temperatures, but at 25°C beetles tended to succumb to bacterial infection. The effect of relative humidity on infection of larvae by B. bassiana (one strain), M. anisopliae (one strain), and P. farinosus (one strain) was tested at 51, 74, 86, 90, 95, 97.5, and 100% relative humidity. B. bassiana and M. anisopliae caused some infection at all humidities: with P. farinosus there was no infection at the two lowest humidities. Mortality due to infection by these fungi was most rapid at the highest humidities.
The ‘Galleria bait method’ originally described for trapping of entomoparasitic nematodes in soil has been used successfully also for the detection of naturally occurring entomopathogenic fungi. In many soil samples several species, such as Beauveria bassiana, Metarrhizium anisopliae or Paecilomyces fumosoroseus, could be detected. This method can be applied for various ecological studies independent of the season and the occurrence of soil inhabiting host insects.
Die “Galleria-Köder-Methode” zum Nachweis von insektenpathogenen Pilzen im Boden
Die ursprünglich zur Entdeckung von insektenparasitischen Nematoden im Boden entwickelte “Galleria-Köder-Methode” wurde auch zum Nachweis von natürlich vorkommenden insektenpathogenen Pilzen erfolgreich cingesetzt. Mit Hilfe dieses Verfahrens konnten mehrere Arten, wie Beauveria bassiana, Metarrhizium anisopliae oder Paecilomyces fumosoroseus, in zahlreichen Bodenproben nachgewiesen werden. Die Methode kann unabhängig von der Jahreszeit und vom Vorhandensein von bestimmten Wirtsinsekten im Boden für unterschiedliche ökologische Untersuchungen angewendet werden.
The principal environmental factors affecting the efficacy of the white and green muscardine fungi Beauveria bassiana and Metarrhizium anisopliae as biological control agents for the pales weevil, Hylobius pales, were investigated. The fungi required relative humidities above 92.5% and temperatures between 15° and 35°C for spore germination, mycelial growth, and sporulation. Optimum germination, growth, and sporulation occurred at 100% RH and at 25–30°C. The thermal death point for spores of both species was near 50°C. Spores stored at 21°C lost all viability after only a few months, whereas spores stored at 8°C remained viable for at least one year. Development of the fungi was inhibited on unsterilized soil, duff, and litter, but spores were able to germinate on the unsterilized cuticle of pales weevils. Once established, both muscardine fungi exhibited striking antibiotic properties.These results indicate that the moisture and temperature conditions in the habitat of the pales weevil are suitable for development of the muscardine fungi. However, since both pathogens are restricted to certain insects for their development, they are unlikely to increase in abundance growing as saprophytes.
A study of the fungal flora of soils, plant leaves, and litter was undertaken on the Truelove Lowland, on the north coast of Devon Island, N.W.T., Canada. A total of 53 taxa from 33 genera were identified, 27 from leaves and litter and 46 from soil, using soil-washing and plating as isolation methods. The predominant fungi on leaves and litter of Carex stans and Dryas integrifolia were sterile fungi, associated with Cladosporiuin, Phoma herbarum. Penicillium spp., and yeasts. Sterile fungi, Penicillium spp. and Chrysosporium pannorum were predominant in raised beach soils, whereas a new species of Cylindrocarpon, sterile fungi. Penicillium, and Aspergillus species predominated in meadow soils. Use of direct observation methods showed that fungal biomass in meadow soils was much higher than in raised beach soils. In raised beach soils fungal biomass was heavily influenced by the distribution of cushion plants. In comparison with other tundra regions, the Truelove Lowland appears to have a moderately rich mycoflora, containing taxa common both in temperate regions and in other tundra soils. Total fungal biomass in Truelove Lowland soils was found to be low in comparison with many tundra regions.
A thorough review of the literature shows that 32 alleged species have been involved in the genera Beauveria and Tritirachium. Fourteen of these are reduced to synonymy with B. bassiana and B. tenella; ten belong to the form genus Tritirachium; one, "Tritirachium epigaeum", is regarded as uncertain as to genus; and seven are excluded from both. Beauveria stephanoderis, B. laxa, B. globulifera, B. effusa, B. vexans, B. doryphorae, B. delacroixii, and B. acridiorum are strains of B. bassiana; while B. densa, B. melolonthae, B. brongniartii, and B. shiotae are strains of B. tenella. The species T. dependens, T. album, T. spicatum, T. oryzae, T. heimii, T. brumpti, T. musae, T. purpureum, T. cinnamomeum, and T. roseum are characteristic of the form genus Tritirachium. Beauveria peteloti, B. rileyi, B. paranense, B. coccorum, B. coccospora, T. rubrum, and T. viannai are characteristic of neither genus. The above conclusions are based on a study of the cultural and morphological characteristics of numerous Beauveria isolates from 70 insect and four rodent species. Most characteristics adopted by earlier investigators to differentiate between Beauveria species are not valid as criteria upon which to establish species. Moreover, these characteristics are unstable and can be changed simply through monospore culturing or by transferring cultures from one type of medium to another. From a review of the literature, it is evident that: members of the genus Beauveria are primarily parasitic on insects, whereas members of the genus Tritirachium are primarily saprophytes.
This muscardine fungus was the organism most frequently encountered in a survey for pathogens of the smaller European elm bark beetle, Scolytus multistriatus Marsh., and was found in larvae from five widely separated areas in Connecticut. Up to 6.5% of overwintering larvae in trees cut from city streets were infected, but under certain environmental conditions the fungus may be much more effective in killing the beetles. In one epizootic caused by this fungus, 97% of larvae were killed in the bark of trees in a shady grove, less than 4% in nearby trees standing in the open. In controlled laboratory experiments the fungus killed up to 99% of the larvae in 5 days. Pupae and adults were also susceptible, though adults were slightly less so than larvae.
Within the field of biological control, there is a strategy that involves the attempt to control a native pest species with an exotic biological control agent. This strategy has been termed neoclassical biological control, and its ecological foundation differs markedly from other forms of biological control. Neoclassical biological control with a parasitic wasp and an entomophagous fungus from Australia is now being applied to rangeland grasshoppers in the western United States. Available evidence suggests that the costs of such a strategy greatly exceed the benefits. Although the probability of successful establishment may be low, if such an agent is established there are a number of possible nontarget impacts. Adverse effects include competitive suppression or extinction of both native biological control agents and nontarget acridids, which comprise the vast majority of extant grasshopper species. Suppression of nontarget acridids may result in loss of biological diversity, existing control of weed species, release of otherwise innocuous acridid species from competitive regulation, disruption of plant community structure, suppression of essential organisms vectored by grasshoppers, and disruption of food chains and other nutrient cycling processes. These impacts are particularly serious given that an established exotic agent is essentially permanent and spatially unbounded. Given that the value of the rangeland resource depends upon the largely unknown ecological processes that underlie its sustainable productivity, there are a number of management techniques that offer a greater probability of success with a markedly lower likelihood of ecological and economic disruption than does neoclassical biological control.
A metabolite of a common soil fungus, Penicillium urticae, which inhibits conidia germination and growth of Beauveria bassiana, was identified. The production, extraction from the culture, and purification of the metabolite is described. Two-dimension thin-layer chromatography, reverse-phase chromatography, mass spectrophotometer and bioassay data indicate that the metabolite is patulin. The implication of patulin inhibition of B. bassiana and its subsequent effect on the potential role of B. bassiana as a control agent of soil-inhabiting insects is discussed.
Metarhizium anisopliae is a well-known entomopathogenic fungus active against many insect pests. This paper discusses the characteristics of M. anisopliae and related species of the same genus, its natural occurrence and host range, identifies the current target pest species and reports some new aspects in production and formulation; present safety data are summarized. Investigations on this fungus demonstrate that M. anisopliae can be an efficient biocontrol agent.
Conidial germination in three strains each of Metarhizium anisopliae and Beauveria bassiana at 20–35°C was investigated. The lag phase for M. anisopliae strains was generally less than for B. bassiana at a given temperature and was temperature-dependent. However, B. bassiana strain 206–85 had a very short lag phase that was independent of temperature. The germination rate was species-dependent, with M. anisopliae strains having faster rates than B. bassiana. The combination of germination rate and lag phase resulted in M. anisopliae strains having higher germination levels (95% germination in 10–14 h) compared with the best B. bassianastrain (206–85; 95% germination in 14–15 h). These results demonstrate intra-specific differences in the germination response which should be considered when selecting isolates for development as myco-insecticides.
Unsterilized aqueous extracts of soil inhibited germination of conidia and germtube growth in the fungi Beauveria bassiana and Paecilomyces farinosus. Extracts of the deepest layer of soil were less inhibiting than extracts of overlying layers of humus-rich soil and partially decomposed leaves. The inhibitory properties were reduced by autoclaving and by filtering the extracts. One percent dextrose () and an aqueous extract of the silk of Bombyx mori cocoon increased the percentage germination and germ-tube growth in both fungi, and also reduced the inhibitory effects of the soil extracts on B. bassiana conidia. Though these amendments improved germination of P. farinosus conidia in the extract of the deepest layer of soil, they failed to improve appreciably their germination in extracts of the upper soil layers. Inhibitors in the soil were found to be capable of diffusing through agar and to be fungistatic rather than fungicidal.
Overwintered larvae, and pupae of the codling moth were scraped from apple tree trunks in spring 1981–1984 and investigated for parasites and pathogenes. The total mortality ranged from 49.6 to 77.8 %. Elodia morio Fall. (Tachinidae) was the most common species among the parasites that emerged during the years (50.6 %). Possible reasons why a higher percentage of E. morio were found in this investigation as compared with other european countries are discussed. Pristomerus vulnerator Panz. (Ichneumonidae) and Ascogaster quadridentatus Wesm. (Braconidae) were the second most common (22.9 and 14.7 %, respectively). Of the cadavers collected in 1981–1982, the fungal pathogenes Beauveria bassiana (Bals.) Vuill. and Paecilomyces farinosus (Dicks, ex Fr.) Brown et Smith, accounted for an infection rate of 34.4 and 29.5 %, respectively. Totally 26.2 % of the experimentally exposed overwintering codling moth larvae were taken by birds. Although based on a small number of samples, birds showed a clear tendency to density‐dependent predation.
Zusammenfassung
Die natürlichen Feinde des Apfelwicklers (Laspeyresia pomonella L.) (Lep., Tortricidae) und ihr Einfluß auf überwinternde Populationen in Südschweden
Überwinterte Larven sowie Puppen des Apfelwicklers wurden 1981–1984 im Frühling von Apfelbaumstämmen geschabt und auf Parasiten und Pathogene untersucht. Die Gesamtmortalität lag zwischen 49,6 und 77,8 %. Elodia morio Fall. (Tachinidae) war die häufigste Art unter den im Verlauf der Jahre schlüpfenden Parasiten (50,6 %). Die möglichen Gründe, weshalb in dieser Untersuchung ein höherer Prozentsatz von E. morio als in anderen europäischen Ländern gefunden wurde, werden diskutiert. Pristomerus vulnerator Panz. (Ichneumonidae) und Ascogaster quadridentatus Wesm. (Braconidae) waren die nächsthäufigsten Arten (22,9 bzw. 14,7 %). In 1981 und 1982 eingesammelten, abgestorbenen Exemplaren wurden die Pilze Beauveria bassiana (Bals.) Vuill. und Paecilomyces farinosus (Dicks. ex Fr.) Brown et Smith, mit 34,4 bzw. 29,5 % gefunden. Von experimentell ausgebrachten, überwinternden Apfelwicklerlarven wurden insgesamt 26,2 % von Vögeln gefressen. Trotz der geringen Probenzahl ließen Vögel eine deutliche Tendenz zur dichteabhängigen Prädation erkennen.
Selected strains ofMetarhizium anisopliae (Metsch.) Sor. were grown on oat grain and tested in field experiments againstOryctes rhinoceros L. It was found thatM. anisopliae survived in breeding site materials for at least 24 months, with survival not greatly affected by the type of material or
by seasonal factors. Naturally occurring breeding sites were examined 3 months after they had been surface treated with oat
grain inoculum ofM. anisopliae. In most sites all the larvae had been killed by the fungus while some contained both diseased and apparently healthy larvae.
Recommendations are made for the use ofM. anisopliae as part of a general control programme for this coconut pest.
Certains types sélectionnés deMetarhizium anisopliae ont été cultivés sur des grains d'avoine et examinés en tant qu'insecticides biologiques au cours d'expériences pratiques
contre lesOryctes rhinoceros. Les résultats ont montré queM. anisopliae peut survivre sur les matériaux du lieu de culture pendant au moins vingt-quatre mois, leur survie n'étant pas particulièrement
affectée par le type de matériel ou par les facteurs saisonniers. Les lieux de culture naturels ont été examinés trois mois
après qu'ils aient été traités superficiellement par l'inoculum de grain d'avoine deM. anisopliae. La plupart des lieux de culture contenaient seulement des cadavres de larves d'O. rhinoceros tués par le champignon tandis que certains autres contenaient à la fois des larves malades et des larves en apparence saines.
L'utilisation deM. anisopliae est recommandée dans le cadre du programme général de lutte contre cet insecte nuisible qui s'attaque à la noix de coco.
Polymerase chain reaction (PCR)-based technology, involving random amplification of polymorphic DNA (RAPD), was used to assess the genomic variability between 24 isolates of deuteromycetous fungi (Metarhizium anisopliae, Metarhizium flavoviride, unidentified strains of Metarhizium and Beauveria bassiana) which were found to infect grasshoppers or locusts. M. flavoviride showed little intraspecific variability in PCR-amplified fragments when compared to M. anisopliae. The high level of variability in PCR-amplified fragments contained within M. anisopliae was similar to the total variability between B. bassiana, M. anisopliae and M. flavoviride, and suggests that M. anisopliae may include a number of cryptic species. Four polymorphic RAPD fragments were used to probe the genomic DNA of the various species and strains. On the basis of these probes the fungi can be grouped into M. flavoviride, M. anisopliae, or B. bassiana. According to PCR-amplified fragments, previously-unidentified Metarhizium strains were characterized as M. flavoviride. There was little evidence that these fungi, all isolated from, or virulent towards, grasshoppers or locusts, showed host-selection in PCR-amplified fragments. Nor was geographical origin a criterion for commonalty based on PCR-amplified fragments. PCR-fragment-pattern polymorphisms and the construction of probes from one or more of these fragments may provide a useful and rapid tool for identifying species and strains of entomopathogenic fungi.
Beauveria bassiana conidia were stored in sterile and nonsterile soil under various temperature, relative humidity, soil water content, and pH regimes. Survival of the conidia was primarily dependent on temperature and soil water content. Conidia half-lives ranged from 14 days at 25°C and 75% water saturation to 276 days at 10°C and 25% water saturation. Conidia held at −15°C exhibited little or no loss in viability regardless of water content, relative humidity, or pH. Conidia were not recoverable after 10 days from soils held at 55°C. Conidia survival in nonsterile soil that was amended with carbon sources, nitrogen sources, or combinations of carbon and nitrogen was greatly decreased and loss was often complete in less than 22 days whereas sterile soil treated in the same manner showed dramatic increases in number, demonstrating that B. bassiana is capable of growth in sterile soil. The obvious fungistatic effect in amended nonsterile soils was possibly related to Penicillium urticae which was routinely isolated from the soils and is shown to produce a water-soluble inhibitor of B. bassiana. The fungistatic effect was shown to be an active inhibition rather than due to competition.
The occurrence of Metarhizium anisopliae, Beauveria bassiana, Paecilomyces farinosus and P. fumosoroseus in natural and agricultural soils of Finland was studied with the insect bait method on 590 soil samples taken in 5 yr. B. bassiana was isolated from 19·8%, M. anisopliae from 15·6%, P. farinosus from 9·2% and P. fumosoroseus from 1% of the samples. The relative importance of geographical location, habitat type and soil type to the occurrence of the fungi was analysed with stepwise logistic regression. Geographical location was the strongest factor determining the occurrence of M. anisopliae, a southern species in Finland. B. bassiana and P. farinosus were adversely affected by cultivation, but M. anisopliae was not P. farinosus occurred throughout Finland, whereas B. bassiana became more common northwards. Soil type did not affect the occurrence of any of the species. P. fumosoroseus occurred only in southernmost Finland, and was never isolated from intensely cultivated soils. The differing distributional patterns of the fungi are discussed with respect to the temperature requirements of the species and their modes of long-term survival in soil.
Four hundred and nineteen pasture soil samples yielded 132 M. anisopliae var. anisopliae isolates, which were classified into 14 strains. The distribution of the strains varied with soil-type and average annual rainfall. Soil pH, conductivity, temperature and altitude had minor or no effect on distribution. Canonical Variate Analysis as used to plot the relative positioning of strains in relation to the environmental variables. The densities of strains (c.f.u. g−1 soil) were not significantly different (P > 0·05). Modal density was 1 × 103 c.f.u. g−1 soil. The density was not correlated with any of the environmental variables examined.
Genetic variation among isolates of Beauveria spp. was defined by an analysis of electrophoretically demonstrable allelic variations of allozyme coding genes. One hundred and forty-six isolates from diverse geographical locations were assigned to forty-seven distinctive genotypic classes. Clustering analysis demonstrated that four morphological species (B. brongniartii, B. vermiconia, B. caledonica and Tolypocladium cylindrosporum) were genetically distinct from each other. However, with the exception of B. brongniartii, which clustered separately with B. amorpha, they were not clearly resolved from lines of B. bassiana. The level of genetic distance shown between cluster groups of B. bassiana indicated that it represents a species aggregate, components of which display overlapping genetic variability with isolates currently assigned to other species. All isolates were homozygous at each locus, consistent with haploidy, except for B. caledonica, which was heterozygous at one of the four loci. In spite of the maintenance of high diversity in B. bassiana, three geographically widespread genotypic classes were found to contain the majority of isolates. This suggests that, in many situations, B. bassiana exists with a clonal population structure. Various other aspects of the allozyme data (the magnitude of genetic distances between populations, gene diversity, and the pattern of distribution of genotypic classes) indicate that chromosomal recombination between different genotypes of B. bassiana spp. is rare or absent.
Intra- and interspecific variation of thirty-two isolates assignable to the genus Beauveria was evaluated using 64 morphological and biochemical characters. Two isolates of Tolypocladium cylindrosporum were included to test generic concepts. Seventeen cluster groups were obtained following a numerical taxonomic analysis, each group being separated by at least one character. Cultural characters were highly variable and could not be used reliably for species determination. Spore form was the most useful criterion to distinguish between species. Biochemical data generally supported species concepts based purely on morphology, with the exception of B. bassiana which comprised a heterogeneous assemblage of strains. There is evidence from API ZYM and esterase patterns that this variability is determined by host (substrate) and geographical origins. B. alba, although morphologically close to B. bassiana, could be separated readily on biochemical characters using principal component analysis. The following species of Beauveria are recognized: B. alba, B. amorpha, B. bassiana, B. brongniartii, B. velata, B. vermiconia and an undescribed taxon close to B. amorpha but morphologically and biochemically distinct. Both isolates of T. cylindrosporum cluster in the same group and, on the basis of present evidence, particularly conidiogenesis, the synonymy of this genus with Beauveria is questioned.
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Untersuchungen zum naturlichen Vorkommen von entomopathogenen Pilzen und Nematoden in verschiedenen Boden in der Umgebung von Darmstadt
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We observed that B. bassiana preferred natural habitats, and M. anisopliae preferred agricultural, cultivated habitats. This phenomenon has also been observed for these fungi in Europe
- Mietkowski
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