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Effect of neonicotinoid synergists on entomopathogenic nematode fitness
Abstract
In previous greenhouse and field studies, the neonicotinoid insecticide imidacloprid interacted synergistically with five entomopathogenic nematode species against five scarab species. Two other neonicotinoids, thiamethoxam and acetamiprid, showed a weaker interaction with nematodes in scarab larvae. Entomopathogenic nematodes have the potential to recycle in hosts after inundative applications, thereby increasing the persistence of nematodes and insect control. Thus we investigated the effect of neonicotinoids on nematode fitness after tank mixing and after combined applications. Tank mixing only had a negative effect on nematode survival and infectivity in a few nematode–insecticide combinations and only if both insecticide concentration and exposure time were several times higher than typical for field applications. Combined application of nematodes with imidacloprid generally had no negative effect on the percentage of scarab cadavers producing progeny or the number of nematode progeny emerging per cadaver. In experiments with a synergistic increase in scarab mortality, the total number of progeny in combination treatments was up to four times higher than in nematodes only treatments. Similarly, nematode populations in soil from combination treatments were 13.2 times greater than for nematodes only treatments at 28 days after treatment. Combined imidacloprid–nematode applications did not affect the pathogenicity or infectivity of the nematode progeny. Combining thiamethoxam with nematodes had no negative effects on nematode reproduction in the majority of treatments. However, due to the weaker interaction of thiamethoxam and nematodes on scarab mortality, the total number of nematode progeny per treatment generally did not increase compared with nematodes only treatments. The demonstrated tank mix compatibility of imidacloprid and nematodes improves the feasibility of combining these agents for curative white grub control. The positive effect of imidacloprid on nematode reproduction after combined application may increase the likelihood of infection of white grubs by subsequent generations of nematodes, thereby improving their field persistence and biological control potential.
... In the study of Laznik and Trdan (2014), azadirachtin, a toxin of B. thuringiensis var. kurstaki, and imidacloprid reduced the number of IJs of the species S. carpocapsae, which was incongruent with similar studies in which the stated active ingredients did not have any effect on the survival or infectiveness of this species Grewal et al., 1998;Koppenhöfer et al., 2003;Alumai and Grewal, 2004). On the basis of the data, we hypothesize that the strain C101 and the commercial preparation with the active ingredient S. carpocapsae are genetically more similar than other aforementioned strains of S. carpocapsae. ...
... Halofenozide Haloxyfop Heptenophos I Imidacloprid (Koppenhöfer et al., 2003;Laznik and Trdan, 2014) Ioxynil (Rovesti and Deseö, 1990) L Lambda cyhalothrin + chlorantranilprole ) L-flamprop isopropyl (Rovesti and Deseö, 1990) Lenacil (Rovesti and Deseö, 1990) Lindane (Rovesti and Deseö, 1990) Lufenuron Lambda cyhalothrin Laznik and Trdan, 2014) Lecithin Lufenuron M ...
... T Tebuconazole (Sterk et al., 1999) Teflubenzuron (Sterk et al., 1999) Terbufos (Rovesti and Deseö, 1990) Thiamethoxam (Koppenhöfer et al., 2003;Alumai and Grewal, 2004) Thiamethoxam + lambda cyhalothrin Thiram (Rovesti and Deseö, 1990) Tolclofos-methyl Tolylfuanide Triflumuron Triforine (Rovesti and Deseö, 1990) Triazofos Trichlorfon Triflumuron Trifluralin (Rovesti and Deseö, 1990) V Vamidothion (Prakasa Verticillium lecanii (Barbarossa et al., 1996) W White oil (Rovesti and Deseö, 1990) ...
This book contains chapters that capture the full breadth of the basic and applied information on entomopathogenic (EPNs) and slug parasitic nematodes (SPNs) that are used or have potential in the management of insect pests, molluscs and/or other researched targets such as plant parasitic nematodes. The information includes the remarkable developments and latest achievements in this direction. The volume is divided into seven parts. The two chapters in Part I introduce comprehensive information on beneficial nematodes in general and their importance, with emphasis on crop pest management. In Part II, there are four chapters devoted to covering the different aspects of the morphology, taxonomy, biology and diversity of EPNs. Part III deals with EPNs and their symbiotic bacteria against crop insect pests and consists of seven chapters. Four chapters describe their role in the management of such insects in the orders Lepidoptera, Coleoptera and Diptera, as well as stored grain pests. Two chapters address the toxic secretions of the EPN-mutualistic bacterial species in the two genera Xenorhabdus and Photorhabdus , and their efficacy against crop insect pests either singly or with EPNs. The last chapter of this part is devoted to the mass production, formulation and application of EPNs. Part IV addresses 11 developed and developing countries as points in case, where the role of EPNs in the integrated pest management strategies implemented in each of these countries is presented. Part V presents the genetics for enhancing the efficacy of EPNs. It contains two chapters dealing with nematode breeding, as well as classical and current methods to achieve such an enhancement. Part VI has three chapters organized for SPNs. In Part VII, there are three chapters to conclude the potential commercialization and future prospects of EPNs and SPNs.
... Imidacloprid, for instance, was shown to be a synergist for the fungal entomopathogen Metarhizium anisopliae (Metchnikoff) Sorokin against the burrower bug Cyrtomenus bergi Froeschner (Jaramillo et al., 2005), as well as for B. bassiana against the root weevil Diaprepes abbreviatus (L.) McCoy, 1997, 1998). Imidacloprid and other neonicotinoids are also known synergists of entomopathogenic nematodes against scarab beetle larvae (Koppenhöfer and Kaya, 1998;Koppenhöfer et al., 2003). The strategic combination of biological controls with reduced rates of chemical insecticide synergists may therefore represent a valuable approach for the suppression of soil insect pests. ...
... Contrary to our results, Koppenhöfer et al. (2002) discerned a synergy between H. bacteriophora and imidacloprid for P. japonica, but not for A. majale. And while the same study showed a similar synergy in P. japonica with thiamethoxam, a later study only reported an additive effect for both imidacloprid and thiamethoxam (Koppenhöfer et al., 2003). In another study (Koppenhöfer et al., 2002), H. bacteriophora combined with imidacloprid and acetamiprid had only an additive effect on A. majale and M. castanea, but with thiamethoxam it had an antagonistic effect. ...
... Multiyear research has shown that interventions against A. majale may be warranted only 20% of the time in both home lawn and golf course settings in New York (Nyrop et al., 1995). Tank mixes could be a feasible way to minimize application costs associated with such an approach, as certain combinations of chemical and biological insecticides can be mixed without affecting the quality of the biological agent or the synergistic effect (Neves et al., 2001;Koppenhöfer et al., 2003). The approach might also supplant reliance on chemical insecticides since it would broaden opportunities for biological alternatives beyond preventive control windows. ...
Synergistic combinations of biological and chemical insecticides might yield promising alternatives for soil insect pest management. In turfgrass of the Northeast U.S., control of root-feeding scarab larvae is highly dependent on conventional insecticides. Studies on interactions between entomopathogenic nematodes and neonicotinoid insecticides, however, demonstrate the feasibility of synergies as an approach for reduced-risk curative control. To understand the breadth of potential synergies, we screened numerous combinations of biological control agents with sublethal doses of neonicotinoids against third instars. Interactions were characterized as synergistic, additive or antagonistic. The most promising combinations identified in laboratory bioassays were advanced to greenhouse pot studies and then to field trials featuring microplots with artificially infested populations. To reveal variation across scarab species, trials were conducted on Amphimallon majale and Popillia japonica. Synergies were consistent across trials and specific to white grub species. For A. majale, synergistic combinations of Heterorhabditis bacteriophora with imidacloprid and clothianidin were discernible in laboratory, greenhouse and field trials. For P. japonica, synergistic combinations of Beauveria bassiana and Metarhizium anisopliae with both neonicotinoids were discernible in the laboratory and greenhouse, but not in the field. For both species, antagonistic interactions were discernible between Bt-products and both neonicotinoids. While nematode-neonicotinoid synergies among scarab larvae have been examined before, fungi-neonicotinoid synergies are unreported. In the context of previous studies, however, no patterns emerge to explain variation across target species or control agent. Further study of non-additive interactions will guide how biological and chemical products could be combined to enhance soil insect pest management.
... Due of the unique characteristics of the nematode-bacterium complicated they are regarded as microorganisms in certain countries and most considers microorganisms and anyway are regulated differently. Nematodes are multicellular creatures and should not be categorized as microbes, according to extensive study conducted by the Organization for the co-operation and development of economies (OECD) and the European Commission's Collaboration in the Field of Science and Technical study (COST) (da Silva et al., 2013;Koppenhöfer et al., 2003;Garcia-del-Pino et al., 2018). Therefore, if the newly introduced species are non-native nematodes, they must comply with the following recommendations and adhere to most of the provisions Following the FAO Code of Conduct for biological control acquisition and distribution (FAO 1996): entomopathogenic nematodes must be identified through morphological characters, either by DNA analysis or both, by a reputable laboratory; the collected samples should be at least frozen in the laboratory to improve DNA analysis in the future; In the first step, the target pests are identified and then the nematodes are applied to it; Before the entomopathogenic nematodes are released, it is best to identify species of its and use them on identified insects, as well as other control methods to justify a release; Any nematode identified before use is best used professionally or in accordance with the principles of the Convention on Biological Diversity; Information on the origin, known dissemination, and potential domain of the exotic entomopathogenic nematode, and its safety for the user should be provided; it is very important to have the opinion and approval of a specialist based on the data at hand regarding the potential consequences of non-target organisms is preferred (Ebssa et al., 2006;Georgis, 2018;Koppenhöfer et al., 2003;Shapiro-Ilan et al., 2006;Niekerk & Malan, 2014). ...
... Nematodes are multicellular creatures and should not be categorized as microbes, according to extensive study conducted by the Organization for the co-operation and development of economies (OECD) and the European Commission's Collaboration in the Field of Science and Technical study (COST) (da Silva et al., 2013;Koppenhöfer et al., 2003;Garcia-del-Pino et al., 2018). Therefore, if the newly introduced species are non-native nematodes, they must comply with the following recommendations and adhere to most of the provisions Following the FAO Code of Conduct for biological control acquisition and distribution (FAO 1996): entomopathogenic nematodes must be identified through morphological characters, either by DNA analysis or both, by a reputable laboratory; the collected samples should be at least frozen in the laboratory to improve DNA analysis in the future; In the first step, the target pests are identified and then the nematodes are applied to it; Before the entomopathogenic nematodes are released, it is best to identify species of its and use them on identified insects, as well as other control methods to justify a release; Any nematode identified before use is best used professionally or in accordance with the principles of the Convention on Biological Diversity; Information on the origin, known dissemination, and potential domain of the exotic entomopathogenic nematode, and its safety for the user should be provided; it is very important to have the opinion and approval of a specialist based on the data at hand regarding the potential consequences of non-target organisms is preferred (Ebssa et al., 2006;Georgis, 2018;Koppenhöfer et al., 2003;Shapiro-Ilan et al., 2006;Niekerk & Malan, 2014). ...
An essential part of managing insect pests is the use of entomopathogenic nematodes and in preventing environmental contamination. Their use has been increasing in recent years. So far, about 30 to 40 nematode families are in contact with insects and other vertebrates. Among these families, the group widely studied as the so-called "entomopathogenic nematodes," also known as EPN, are Heterorhabditidae and Steinernematidae. Two species of Oscheius (Oscheius chongmingensis and Oscheius carolinensis) have been added in recent years to the EPNs group, and we expect that several species will be added to EPNs. ENP has a wide range of host insects found in a species of EPN that can attack over 250 different kinds of insects from several families. Suitable environments for EPNs include insect hemocoels, soil pores, or river bottoms that grow in contact with these environments. Occurrence, mobility, distribution, and stability of EPN under the influence of several factors, including intrinsic factors such as behavioral, physiological, and genetic characteristics. Biological nature included are hosted and non-host arthropods, predators, parasites, diseases, and aberrant environmental elements like temperature, moisture content, texture, pH, and UV radiation. Proper mass production and application are essential for the biological control effectiveness of entomopathogenic nematodes (EPN). In addition, there is no problem in applying EPNs because they are simple to spray with common equipment and are compatible with almost all chemical fertilizers, but the compatibility is different from chemical pesticides.
... Several insecticides have been found to work in tandem with EPNs for the management of white grubs. For example, chlorantraniliprole could be blended with H. bacteriophora against Anomala orientalis and Popillia japonica (Koppenhöfer and Fuzy, 2008a), while imidacloprid could be mixed with several nematode species against five scarab species (Koppenhöfer et al., , 2003Koppenhöfer and Grewal, 2005;Koppenhöfer and Fuzy, 2008b). Studies have shown that combining S. longicaudum and H. bacteriophora with insecticides like chlorantraniliprole, diflubenzuron, or imidacloprid increased the curative control of the white grub, Holotricha oblita in field conditions. ...
... kurstaki toxin, and imidacloprid, the number of IJs of S. carpocapsae lowered. However, the findings were contrary to the results obtained by other workers who reported that active ingredients had no effect on the species' survival or infectivity (Barbarossa et al., 1996;Grewal et al., 1998;Koppenhöfer et al., 2003;Alumai and Grewal, 2004). Some other factors which influence the survival of IJs are mentioned under the following subheadings. ...
Entomopathogenic nematodes (EPNs) are environmentally friendly, safe and effective biocontrol agents for a variety of insect pests that harm agricultural and horticultural crops. They have been reported from all over the world and mass-produced for utilization against insect pests. When used in conjunction with pesticides, these EPNs have shown better outcomes. The growing interest in organic agriculture as an alternative to synthetic pesticides creates prospects for the integrated use of EPNs and insecticides in agricultural pest management. However, EPNs first need to be enhanced in terms of efficacy, cost savings, and convenience of use. Furthermore, their ability to recycle in the host and their tolerance to various chemical pesticides used in agriculture needs to be explored for
long-term pest control. This chapter summarizes significant progress made in the research and application of EPNs in combination with chemical pesticides for insect pest management programs.
... Several insecticides have been found to work in tandem with EPNs for the management of white grubs. For example, chlorantraniliprole could be blended with H. bacteriophora against Anomala orientalis and Popillia japonica (Koppenhöfer and Fuzy, 2008a), while imidacloprid could be mixed with several nematode species against five scarab species (Koppenhöfer et al., , 2003Koppenhöfer and Grewal, 2005;Koppenhöfer and Fuzy, 2008b). Studies have shown that combining S. longicaudum and H. bacteriophora with insecticides like chlorantraniliprole, diflubenzuron, or imidacloprid increased the curative control of the white grub, Holotricha oblita in field conditions. ...
... kurstaki toxin, and imidacloprid, the number of IJs of S. carpocapsae lowered. However, the findings were contrary to the results obtained by other workers who reported that active ingredients had no effect on the species' survival or infectivity (Barbarossa et al., 1996;Grewal et al., 1998;Koppenhöfer et al., 2003;. Some other factors which influence the survival of IJs are mentioned under the following subheadings. ...
... Several insecticides have been found to work in tandem with EPNs for the management of white grubs. For example, chlorantraniliprole could be blended with H. bacteriophora against Anomala orientalis and Popillia japonica (Koppenhöfer and Fuzy, 2008a), while imidacloprid could be mixed with several nematode species against five scarab species (Koppenhöfer et al., , 2003Koppenhöfer and Grewal, 2005;Koppenhöfer and Fuzy, 2008b). Studies have shown that combining S. longicaudum and H. bacteriophora with insecticides like chlorantraniliprole, diflubenzuron, or imidacloprid increased the curative control of the white grub, Holotricha oblita in field conditions. ...
... kurstaki toxin, and imidacloprid, the number of IJs of S. carpocapsae lowered. However, the findings were contrary to the results obtained by other workers who reported that active ingredients had no effect on the species' survival or infectivity (Barbarossa et al., 1996;Grewal et al., 1998;Koppenhöfer et al., 2003;. Some other factors which influence the survival of IJs are mentioned under the following subheadings. ...
Dealing with different biocontrol agents for the management of plant parasitic nematodes
... Nematodes are a part of soil microfauna and are important participants in soil processes due to their high numbers, diverse feeding types and life history strategies. As for the effects of neonicotinoid insecticides to free-living nematodes, scientific literature is restricted to the sensitivity of entomopathogenic nematodes (EPN) to these compounds (Koppenhöfer et al. 2003;. ...
... The combined effects of thiamethoxam and entomopathogenic nematodes of the order Rhabditida against pest insects were investigated both under field and laboratory conditions. During the tests performed by Koppenhöfer et al. (2003), thiamethoxam did not have a negative effect on the reproduction of entomopathogenic nematodes. This supports the results of our study concerning P. redivivus, which also belongs to the order Rhabditida, i.e. nematodes of this group were not sensitive to thiamethoxam. ...
Cruiser 350 FS (Syngenta) is a widely applied thiamethoxam-containing seed treatment product. Despite
of this fact, little is known about its side effects on non-target organisms other than bees. In this study, the effects of Cruiser 350 FS mixed in soil in different concentrations (according to OECD standards) were investigated on the mortality and reproduction of a Collembola species (Folsomia candida). On the basis of springtail mortality data, an LC50 of 223.6 mg/kg and a NOEC of 24.5 mg/kg were determined for Folsomia candida. The following toxicological limits were obtained on the basis of the reproduction data from the springtail test: EC50: 61.73 mg/kg, NOEC: 12.27 mg/kg. Moreover, mortality tests were performed in microplates on two nematode species of different feeding and reproductive strategies. After 24 hours of exposure, treatment had no effect on mortality up to a concentration of 35 g of thiamethoxam/l in the r-strategist bacterivorous Panagrellus redivivus; while the species-specific LC50 was determined to be 0.19 g/l for Xiphinema vuittenezi. Our results proved the K-strategist plant-feeding X. vuittenezi to be more sensitive than the r-strategist bacterivore P. redivivus. Our results highlight the difference in the sensitivity of nematodes of different feeding and functional groups, suggesting the importance of a more sophisticated study approach.
... Koppenhöfer et al. (2002) avaliaram misturas de H. bacteriophora e S. glaseri com tiametoxam, no controle de larvas de Exomala orientalis (Waterhouse) (Coleoptera: Scarabaeidae), verificando efeitos também sinérgicos quando essas misturas foram comparadas aos nematóides e ao inseticida testados isoladamente. A associação de nematóides entomopatogênicos com o inseticida imidacloprido já vem sendo avaliada para o controle de larvas de escarabeídeos, proporcionando bons resultados de controle e, em muitos casos, apresentando efeitos sinérgicos na mortalidade dos insetos (Koppenhöfer & Kaya, 1998;Koppenhöfer et al., 2000;Koppenhöfer et al., 2003). Comentário A mistura de H. indica com fipronil proporcionou um efeito sinérgico na mortalidade do inseto, porém esse efeito ocorreu somente no primeiro ensaio quando o inseticida foi avaliado na dose de 125 g p.c./ha, bastante acima da dose usada no segundo e terceiro ensaio (62,5 g p.c./ha). ...
... Esses resultados confirmam a compatibilidade desses agentes a esses inseticidas. Os nematóides Heterorhabditis bacteriophora Poinar, 1976 e Steinernema carpocapsae (Weiser, 1955) Wouts, Mràcek, Gerdin & Bedding, 1982 também H. bacteriophora e S. carpocapsae, e o segundo para esses mesmos nematóides, além de Heterorhabditis megidis Poinar, Jackson & Klein, 1987, S. glaseri e Steinenerma feltiae(Filipjev, 1934) Wouts, Mràcek, Gerdin & Bedding, 1982(Koppenhöfer & Kaya 1998Koppenhöfer et al. 2003;Alumai & Grewal 2004).Andaló et al. (2004) avaliaram a compatibilidade de tiametoxam com nematóides entomopatogênicos e constataram que o produto além de não afetar a viabilidade, também não interferiu na infectividade dos nematóides quando inoculados em larvas de G. mellonella.Tabela 1. Viabilidade (± Erro Padrão) dos juvenis infectivos de Steinernema sp. IBCB n-6 e Heterorhabditis indica (IBCB n-5) após exposição por 24 horas aos inseticidas fipronil, tiametoxam e imidacloprido (T=25 ± 1ºC, UR=70 ± Médias seguidas de mesma letra, não diferem entre si pelo teste de Tukey (P ≤ 0,05).Avaliação de Heterorhabditis indica IBCB n-5 eSteinernema sp. ...
The effect of combinations of the entomopathogenic nematodes Heterorhabditis indica Poinar, Karunakar & David, 1992 (strain IBCB-n5) and Steinernema sp. (strain IBCB-n6) at doses of 2.4;12 and 60 IJ/cm2, with sub-doses of the chemical insecticides fipronil, thiamethoxam and imidacloprid were tested in laboratory conditions against adults and larvae of the sugarcane billbug, Sphenophorus levis Vaurie, 1978. Firstly, the effect of fipronil (200 g A.I./ha), thiamethoxam (250 g A.I./ha) and imidacloprid (700 g A.I./ha) were evaluated on the nematode viability. The insecticides were compatible with the nematodes, not affecting the viability of the infective juvenile after 24 hours. For the experiments with adults, the treatments containing nematodes and insecticides tested separately showed mortality below 25%, except for the two highest doses of Steinernema sp. (at 12 and 60 IJ/cm2), with mortality levels of 33.3% and 50% respectively. For the mixtures of the nematodes with sub-doses of thiamethoxam (62.5 g A.I./ha), the mortality levels increased significantly, reaching up to 66.7%, with the mixture of H. indica at 60 IJ/cm2, and 70% to 83.3% at all doses of Steinernema sp., showing synergistic effect at these combinations. The combination of H. indica and Steinernema sp. (12 IJ/cm2) with thiamethoxam (62.5 g A.I./ha) against larva, the nematodes tested alone or in mixture with the insecticides showed mortality levels between 75% and 87.5%, indicating no advantage of the mixture for improving the insect mortality.
... This fact may be important for the persistence of natural populations, as well as for the enhanced recycling of applied EPNs in integrated control programs where hosts killed by some chemicals may be available and suitable for development (Griffin 2012). Hara and Kaya (1983) and Koppenhöfer et al. (2003) reported that EPNs can infect and develop in hosts killed by several insecticides. ...
... Although there have been many studies about the interaction of agrochemicals and EPNs, limited data exists on the capacity of EPNs to infect and reproduce in insects affected by pesticides (Hara and Kaya 1983;Koppenhöfer et al. 2003). Our results confirm the capacity of the nematodes to infect and reproduce in larvae affected by the three insecticides tested. ...
The efficacy of soil treatments of three
native entomopathogenic nematodes (Steinernema
carpocapsae, S. feltiae and Heterorhabditis bacteriophora)
against Tuta absoluta larvae, pupae and adults
was determined under laboratory conditions. The
effect of three insecticides commonly used against
T. absoluta, in the survival, infectivity and reproduction
of these nematode strains was also evaluated.
When dropped into soil to pupate, soil application of
nematodes resulted in a high mortality of larvae: 100,
52.3 and 96.7 % efficacy for S. carpocapsae, S. feltiae
and H. bacteriophora respectively. No mortality of
pupae was observed and mortality of adults emerging
from soil was 79.1 %for S. carpocapsae and 0.5 %for
S. feltiae. The insecticides tested had a negligible
effect on nematode survival, infectivity and reproduction.
No sublethal effects were observed. Infective
juveniles that survived to insecticide exposition were
able to infect Galleria larvae with no significant
differences from the control. The Galleria larvae
affected by the three insecticides tested served as
suitable hosts for the infection and reproduction of the
nematodes. These results suggest that larvae of
T. absoluta, falling from leaves following insecticide
application, could be suitable hosts for nematodes,
thereby increasing their concentration and persistence
in the soil.
... The present study was supported by an earlier work of Priya and Subramanian (2008), where it has been reported that H. indica was compatible with carbofuran, carbosulfan and imidacloprid. Earlier work suggests that neonicotinoid insecticides have fewer adverse effects on nematode survival, pathogenicity, and infectivity (Koppenhöfer et al.,2003). Thiamethoxam and imidacloprid belong to the same insecticide group, i.e., neonicotinoid. ...
Entomopathogenic nematodes (EPNs) have been identified as promising biocontrol agents for controlling economically important insect pests of agricultural and horticultural crops. The compatibility of entomopathogenic nematode Heterorhabditis indica with 7 CIB registered insecticides was investigated under laboratory conditions. The effect of these insecticides on nematode survival at recommended concentrations was observed after 12, 24, 48, 72 hours upon direct exposure. EPN H. indica was compatible with Imidacloprid 17.8% SL as maximum per cent of live H. indica were observed after 72 h of exposure to this insecticide. Similarly, H. indica was compatible with Fipronil 5% SC up to 48 h of exposure whereas, less than 70% live EPN were there in Thiamethoxam 25% WG, Diafenthiuron 50% WP and Cypermethrin 25% EC resulting these insecticides to be least compatible. Emamectin benzoate 5% SG and chlorpyriphos 20% EC were incompatible with H. indica after 48 h of exposure. The result of this experiment will help in reducing the dependence on chemical insecticides and thus slowing down the development of insecticide resistance and preventing adverse effects on public health and the environment.
... Studies carried out by other authors also show low IJ mortality of S. carpocapsae when exposed to chlorpyrifos [28,33,34] . Thiomethoxam was also reported compatible with H. megidis, S. feltae and S. glasseri [35] and with S. carpocapsae [28] . Insecticides like fipronil had also reported compatible with H. bacteriophora and S. carpocapsae [36] and dinotefuran with H. sonorensis and S. riobrave [37] . ...
The compatibility of entomopathogenic nematode Heterorhabditis indica with 14 insecticides, 6 fungicides and 7 herbicides commonly used in rice ecosystems was investigated under laboratory conditions. The effect of these chemicals on nematode viability and virulence upon direct exposure to chemicals at recommended concentrations was studied. H. indica was tolerant to most of the insecticides tested with less than 10% nematode mortality observed in all insecticides except monocrotophos (19.5%) and cartap hydrochloride (100%) after 72 h of exposure. Less than 10% mortality was observed in all fungicides tested except tricyclazole (14.5%) and carbendazium +mancozeb (21.5%) after 72 h of exposure to fungicides. Nematode mortality in case of herbicides ranged from 3.5% to 18% after 72 h of exposure. Insecticides showed only a marginal effect on the virulence of H. indica. Mortality of Galleria mellonella larvae in all the treatments was more than 90% except in treatments with chlorpyrifos (80%) and monocrotophos (60%) treated infective juveniles after 48 h. These results show that H. indica is compatible with all the tested agrochemicals except monocrotophos and cartap hydrochloride among insecticides, tricyclazole and carbendazium+mancozeb among fungicides, and pendimethalin among herbicides.
... EPNs infect their host via spiracles or cuticle, mouth and anus opening as infective juveniles (IJs) (Kaya and Gaugler 1993;Koppenhöfer et al. 2003). EPNs carry mutualistic symbiotic bacteria such as Xenorhabdus spp. ...
Active compounds of biological origin and their synthetic derivatives are in high demand for crop protection over conventional pesticides since synthetic chemicals have reduced availability, adverse toxicological effects, and resistance and pest resurgence issues. Insecticides of biological origin (biopesticides) are less toxic and effective in small quantities and decompose quickly, leaving not much burden on environment. These are mostly target-specific and do not affect nontarget organisms much. Many of the bacteria, fungi, viruses, nematodes, protozoans, plants or plant-derived products (botanicals), pathogen/predator systems, insect pheromones, and plant-incorporated protectants (PIPs) are widely used as biological control agents for insect pest management (IPM). Among all, Bacillus thuringiensis-based biological insecticide has been primarily developed and commercialized. Biotechnological approaches such as transgenic technology and nanotechnology have recently come up that have potential to enhance expression and delivery mechanisms of biopesticide. Though the list is huge, only a limited number of living system-derived compounds have been used commercially, which are amenable to mass production and affordable to the growers. This chapter addresses the recent status of microbial control agents as biopesticides, which is used to improve agricultural productivity by restricting pest infestation.
... The recycling of applied entomopathogenic nematodes is enhanced, particularly when applied during integrated pest management programs where hosts killed by other biological agents or chemical methods may be available and suitable for development. The report of entomopathogenic nematodes developing in hosts killed by insecticides has been confirmed by several workers (Hara and Kaya 1983;Koppenhöfer et al. 2003). Dillon et al. (2006) reported that under field condition the rate of parasitization declined as the depth of the insects in soil increased. ...
Entomopathogenic nematodes Steinernema and Heterorhabditis are excellent biocontrol agents of crop insect pests. These beneficial nematodes decrease the reliance on synthetic pesticides and assist in maintaining a desirable ecological balance. They adapt to a wide range of behavioural strategies, and their degree of efficacy varies with species and the ecological niche where nematode-insect interactions take place. Occurrence and distribution of entomopathogenic nematodes are related to certain insect groups that are considered their suitable hosts. Soil texture and presence of a host affect the nematode’s direction of movement. The specific behaviours and cues used by infective juveniles of different nematode species vary while searching and finding the hosts. The process of infection is governed by several factors such as host recognition behaviour, acceptance behaviour and infection behaviour. Cues such as feces or cuticle associated with living insects affect a nematode’s foraging behaviour which varies with respect to nematode species. Therefore, correct selection of nematode species is of foremost importance in the insect pest management strategies. Apart from nematodes’ habitat preference and infection behaviour, survival strategy and reproductive behaviour are other important parameters that need attention.
... Neonicotinoid-EPN com bination generally had no negative effect on EPN reproduction in hosts. It resulted in higher IJ densities in the soil following application, due to the greater number of infected white grubs (Koppenhöfer et al., 2003). ...
This chapter focuses on the principal and most studied abiotic factors (temperature, moisture, UV, chemical inputs). It provides an updated overview of what has been learned regarding abiotic effects on different entomopathogen groups during the past 30 years. It focuses on entomopathogens that have emonstrated potential roles in microbial control. Abiotic environmental factors have diverse effects on entomopathogen survival, efficacy, and dispersal in the ecosystem. Extreme temperatures, desiccation, and UV radiation have the most detrimental effects on pathogen survival despite the existence of durable resting stages for most groups. Few field studies have investigated the influence of temperature on the severity and rate of transmission of viral disease. Since low temperatures do not affect the lethality of most baculoviruses, these viruses could be applied for area-wide management to reduce pest populations early or before the start of the growing season, as demonstrated against Helicoverpa zea and Heliothis virescens.
... Previous reviews of insect pest management have discussed the pyrethroid and organophosphate classes of chemistry (Turnipseed and Kogan, 1976;Kogan and Turnipseed, 1987). In recent years, several insecticides with new modes of action have come to the market with multiple benefits, including reduced human toxicity, increased efficacy, plant mobility and insect selectivity (Harrewijn and Kayser, 1997;Kunkel et al., 1999;Elbert and Nauen, 2000;Mukherjee and Gopal, 2000;Bostanian et al., 2001;Elzen, 2001;Sechser et al., 2002;Koppenhofer et al., 2003;Ako et al., 2004;Ohnesorg et al., 2009). ...
... Nematode combinations with lowenvironmental impact insecticides such as imidacloprid may offer an efficient alternative that is highly preferable over the use of conventional soil insecticides or widespread applications of imidacloprid. Recently research has shown that imidacloprid enhances the pathogenicity of the Metarhizium anisopliae (Paula et al. 2011), Bacillus thuringiensis (Salem et al. 2007), spinosad enhances the pathogenicity of the Metarhizium anisopliae (Sharififard et al. 2011) and imidacloprid also know to synergists with EPNs against scarab beetle larvae (Koppenhofer and Kaya 1998;Koppenhofer et al. 2003). Our hypothesis was that imidacloprid act as stressor on 3 rd -instar white grubs and increases their susceptibility to EPNs. ...
Insecticide imidacloprid and entomopathogenic nematode (EPN), Heterorhabditis indica alone and in combinations of imidacloprid and EPN were evaluated against early and late 3rd instars of coconut white grub, Leucopholis coniophora. Field collected 3rd instars white grubs were placed in pots with sweet potato treated with imidacloprid, the EPN, or both. In all nematode-imidacloprid combinations, both early and late 3rd instars grub mortality was significantly higher than in the H. indica alone and imidacloprid alone treatments. Combinations of imidacloprid and nematodes had a strong synergistic effect on mortality at different concentrations of imidacloprid. Nematodes were admixed with various concentrations of imidacloprid ranging from 0.04 to 1.25% could not significantly affect the survival of infective juveniles resulting in only a negligible mortality (3.5%). Results revealed that different imidacloprid concentrations, exposure time and interaction between imidacloprid and exposure time not affected nematodes mortality in bioassay. Combinations of imidacloprid and entomopathogenic nematodes may provide a powerful and economically feasible curative control in white grub management in coconut.
... Also combinations of nematodes with chemicals and pathogens have been used to increase nematode effi cacy in laboratory and fi eld applications. Nematodes have been combined with pesticides (Head et al. 2000, Koppenhöfer et al. 2003, adjuvants (Baur et al. 1997), bacteria Kaya 1997, Koppenhöfer et al. 2000), viruses (Agra Gothama et al. 1996) and fungi (Choo et al. 1996). These methods involve a mechanism of stressing the host so that is more susceptible to the nematode infection. ...
Can pre-colonisation of the soil substrate increase the efficacy of entomopathogenic nematodes (Rhabditida: Steinernematidae)?
The effects of soil pre-colonisation with entomopathogenic nematodes Steinernema feltiae, S. carpocapsae and S. arenarium on the mortality of Tenebrio molitor larvae were tested under laboratory conditions. The soil was inhabited with the nematodes for 7 days prior to the addition of the larvae. Nematode concentrations of 50 and 500 infective juveniles per box were used. S. carpocapsae reacted to pre-colonisation negatively and the efficacy decreased at the concentrations tested. S. arenarium showed generally low efficacy against Tenebrio molitor larvae and pre-colonisation showed only a slight positive effect on the efficacy of this species. S. feltiae increased its efficacy at the concentration of 500 infective juveniles per box compared with other tested nematodes.
... Concerning the significant increase in S. frugiperda mortality with time, in treatments with application of EPNs associated to insecticides, Epsky and Capinera (1993) verified that S. frugiperda mortality was correlated positively (exponential response) with time exposure to S. capocapsae in laboratory, in agree with this study. In addition, mortality increase of Popillia japonica Newman, 1841 and Exomala orientalis (Waterhouse, 1875) (Coleoptera: Scarabaeidae) was observed associated with time exposure in laboratory and in the field with the combination of neo-nicotinic insecticides (imidaclopride and tiametoxam) and Heterorhabditis bacteriophora (Koppenhöfer et al., 2002(Koppenhöfer et al., , 2003. ...
The main insect pest in Brazilian corn is fall armyworm, Spodoptera frugiperda (Smith, 1797) (Lepidoptera: Noctuidae). Entomopathogenic nematodes (EPNs) can be used to control this pest, and can be applied together with various insecticides. Thus, the objective of this work was to evaluate the efficacy of mixtures of EPNs and insecticides to control S. frugiperda in corn crops. In laboratory bioassays three species of EPNs were tested (Heterorhabditis indica, Steinernema carpocapsae and Steinernema glaseri) together with 18 registered insecticides to control S. frugiperda in corn. Efficacy of association between insecticides and EPNs on S. frugiperda larvae was evaluated against the insect's third instar, 2 and 4 days after applications in laboratory. Experiments in the field were performed in two consecutive years, with located application of H. indica and S. carpocapsae (250 IJs/cm2) mixed with chlorpyrifos (0.3 L/ha) and lufenuron (0.15 L/ha) on the corn husk. In laboratory, after two days exposure the interaction between chlorpyrifos and H. indica was synergistic, while interaction with cypermethrin, spinosad, methoxyfenozide and deltamethrin + triazofos was additive, as was interaction between lufenuron, chlorpyrifos and cypermethrin with S. carpocapsae. In contrast, the interaction between chlorpyrifos (Vexter™ and Lorsban™) and lufenuron with S. glaseri was synergistic. In the field, the best treatment was the mixture of H. indica with lufenuron (0.15 L/ha), with 62.5% and 57.5% larval mortality in the two evaluation years in the field, respectively.
... EPN can reproduce in host species that they cannot kill (Puza and Mracek, 2010), which may be important for the persistence of natural populations, as well as enhanced recycling of applied EPN, especially in integrated control programs where hosts killed by other biological or chemical agents may be available and suitable for development. For example, EPN can develop in hosts killed by several insecticides (Hara and Kaya, 1983;Koppenhöfer et al., 2003) and by granulosis virus (Kaya and Burlando, 1989). ...
The entomopathogenic nematodes (EPN) Heterorhabditis and Steinernema are widely used for the biological control of insect pests and are gaining importance as model organisms for studying parasitism and symbiosis. In this paper recent advances in the understanding of EPN behavior are reviewed. The "foraging strategy" paradigm (distinction between species with ambush and cruise strategies) as applied to EPN is being challenged and alternative paradigms proposed. Infection decisions are based on condition of the potential host, and it is becoming clear that already-infected and even long-dead hosts may be invaded, as well as healthy live hosts. The state of the infective juvenile (IJ) also influences infection, and evidence for a phased increase in infectivity of EPN species is mounting. The possibility of social behavior - adaptive interactions between IJs outside the host - is discussed. EPNs' symbiotic bacteria (Photorhabdus and Xenorhabdus) are important for killing the host and rendering it suitable for nematode reproduction, but may reduce survival of IJs, resulting in a trade-off between survival and reproduction. The symbiont also contributes to defence of the cadaver by affecting food-choice decisions of insect and avian scavengers. I review EPN reproductive behavior (including sperm competition, copulation and evidence for attractive and organizational effects of pheromones), and consider the role of endotokia matricida as parental behavior exploited by the symbiont for transmission.
... Contrary to this, a synergistic effect of imida‐ cloprid on reproduction of entomopathogenic nematodes against scarab grubs may increase the likelihood of infection by subsequent generations of nematodes, thereby improving their field persistence and biological potential to control grubs. Acetamiprid and thiamethoxam, however, do not show synergist interactions with nematodes [149]. Imidacloprid at 0.1-0.5 mg/kg dry soil disturbs the burrowing ability of Allolobophora spp. ...
This review has brought some light on the direct, sublethal and indirect effects that systemic insecticides have on species populations and ecosystems. Some long-term impacts have been known for some time (e.g. carbofuran, phorate), but it is the rapid increase in the usage of neonicotinoids and other systemic products that poses a new challenge to the ecological risk assessment of agrochemicals. Indeed, current risk protocols, based on acute, short-term toxic affects are inadequate to cope with the chronic exposure and cumulative, delayed impacts of the new compounds. Awareness of the increasing contamination of the environment with active residues of these chemicals should help regulators and managers to implement new approaches for risk assessment of these substances.
... Although none of the treatments tested yielded successful nematode reproduction in all cadavers, G. incorrupta is probably a viable host for these nematodes. Nematodes do not reproduce successfully in all infected hosts (Koppenhö fer and Kaya 1999, Koppenhö fer et al. 2003, Gassmann et al. 2006). There are several reasons why this may occur, for example, nematodes in the genus Steinernema have obligate sexually reproduction during their Þrst generation within an infected host (Burnell and Stock 2000). ...
Tritrophic interactions may include directly harmful effects of host plants on herbivores, and directly or indirectly harmful effects of host plants on the natural enemies of herbivores. Tritrophic interactions involving parasitoids and predators have received considerable attention but less is known about how host plants affect entomopathogens. We compared growth and resistance to entomopathogenic nematodes for “woolly bear caterpillars, Grammia incorrupta (=geneura) (Hy. Edwards) (Lepidoptera: Arctiidae) fed lettuce, Lactuca sativa L. (Asteraceae), versus threadleaf groundsel, Senecio longilobus Benth. (Asteraceae). Both plants are members of the Asteraceae, but only S. longilobus contains pyrrolizidine alkaloids. Caterpillars gained more mass when fed L. sativa compared with S. longilobus; yet, in one of four cases studied, resistance to nematodes was higher when caterpillars ate S. longilobus. Caterpillar resistance to nematodes did not differ between host plants in the other cases. In addition, nematode reproduction was higher in cadavers of G. incorrupta that had been fed L. sativa instead of S. longilobus, suggesting that S. longilobus had indirectly detrimental effects on entomopathogenic nematodes. Our results illustrate how trade-offs may arise in tritrophic interactions involving entomopathogens, as the cost of decreased growth imposed by S. longilobus was accompanied by the benefit of greater resistance to entomopathogenic nematodes.
... Combinations of nematodes with chemicals and pathogens have been used to increase nematode eYcacy in laboratory and Weld applications. Nematodes have been combined with pesticides (Head et al., 2000; Koppenhöfer et al., 2003; Rovesti et al., 1989; Zimmerman and Cranshaw, 1990), adjuvants (Baur et al., 1997), bacteria (Kaya et al., 1995; Koppenhöfer and Kaya, 1997; Koppenhöfer et al., 2000a; Thurston et al., 1993 Thurston et al., , 1994a), viruses (Agra Gothama et al., 1996) and fungi (Choo et al., 1996). Increased susceptibility to entomopathogenic nematode infection has also been demonstrated in several herbivorous insects exposed to plant and fungal secondary metabolites (Barbercheck and Kaya, 1991; Grewal et al., 1995 ). ...
Entomopathogenic nematode in vivo production depends on a high level of successful infection during the inoculation process. Some host–nematode combinations do not provide sufficient or consistent infection levels and are, therefore, not suitable for in vivo production. Our objective was to determine whether infection levels could be improved through host or nematode exposure to physical and chemical stressors. Elevated stress may compromise host insect defenses, thus increasing its vulnerability to nematode infection. Specifically, we investigated the effects of stressors on Heterorhabditis bacteriophora infection of Tenebrio molitor larva. The stressors included temperature extremes, insecticidal oils and metal cations. Most chemical stressor–nematode combinations caused high host mortality and low infectivity rates. However, infective juvenile stimulation by the cation Mn2+ did enhance infectivity compared to the control. Dry heat (40 °C for 30 min) and hot water (60–70 °C for 1 s) treatments increased the host’s susceptibility to H. bacteriophora infection with respect to unstressed controls, and the yields and virulence of infective juveniles produced in hosts stressed by these treatments were not affected. Thus, host stress methods can be used to successfully enhance infection levels for in vivo production of H. bacteriophora.
Many organisms, including beneficial entomopathogenic nematodes (EPNs), are commonly found in the soil environment. EPNs are used as biopesticides for pest control. They have many positive characteristics and are able to survive at sites of application for a long time, producing new generations of individuals. The occurrence of populations depends on many environmental parameters, such as temperature, moisture, soil texture, and pH. Extreme temperatures result in a decrease in the survival rate and infectivity of EPNs. Both high humidity and acidic soil pH reduce populations and disrupt the biological activity of EPNs. Nematodes are also exposed to anthropogenic agents, such as heavy metals, oil, gasoline, and even essential oils. These limit their ability to move in the soil, thereby reducing their chances of successfully finding a host. Commonly used fertilizers and chemical pesticides are also a challenge. They reduce the pathogenicity of EPNs and negatively affect their reproduction, which reduces the population size. Biotic factors also influence nematode biology. Fungi and competition limit the reproduction and survival of EPNs in the soil. Host availability enables survival and affects infectivity. Knowledge of the influence of environmental factors on the biology of EPNs will allow more effective use of the insecticidal capacity of these organisms.
Neonicotinoids are the most widely used class of insecticides in the world, but they have raised numerous concerns regarding their effects on biodiversity. Thus, the objective of this work was to do a critical review of the contamination of the environment (soil, water, air, biota) by neonicotinoids (acetamiprid, clothianidin, imidacloprid, thiacloprid, thiamethoxam) and of their impacts on terrestrial and aquatic biodiversity. Neonicotinoids are very frequently detected in soils and in freshwater, and they are also found in the air. They have only been recently monitored in coastal and marine environments, but some studies already reported the presence of imidacloprid and thiamethoxam in transitional or semi-enclosed ecosystems (lagoons, bays, and estuaries). The contamination of the environment leads to the exposure and to the contamination of non-target organisms and to negative effects on biodiversity. Direct impacts of neonicotinoids are mainly reported on terrestrial invertebrates (e.g., pollinators, natural enemies, earthworms) and vertebrates (e.g., birds) and on aquatic invertebrates (e.g., arthropods). Impacts on aquatic vertebrate populations and communities, as well as on microorganisms, are less documented. In addition to their toxicity to directly exposed organisms, neonicotinoid induce indirect effects via trophic cascades as demonstrated in several species (terrestrial and aquatic invertebrates). However, more data are needed to reach firmer conclusions and to get a clearer picture of such indirect effects. Finally, we identified specific knowledge gaps that need to be filled to better understand the effects of neonicotinoids on terrestrial, freshwater, and marine organisms, as well as on ecosystem services associated with these biotas.
Graphical Abstract
Entomopathogenic nematodes (EPNs) play a crucial role in biological control, but they can be also applied together with pesticides. Therefore, the compatibility of pesticides with EPNs and the influence on their behavior significantly affect field success. This study investigated how selected pesticides (Deltamethrin, Imidacloprid, Pendimethalin, 2,4-D, and Boscalid + Pyraclostrobin) affect the orientation behavior of three commercial EPN species. Trials were conducted using steel olfactometers followed by the assessment of EPN dispersal ratios after 24 hours. The study was conducted in the Laboratory of the Plant Protection Department, Faculty of Agriculture and Natural Sciences, Bilecik Şeyh Edebali University between 2022 and 2023. According to the results, while nearly all pesticides exhibited a significant impact on the dispersal behavior of EPNs, the most notable effects were observed in the trials involving 2,4-D and Imidacloprid. These two pesticides demonstrated both repellent and attractive effects on different EPN species. The impact of other pesticides was comparatively negligible. All EPN species exhibited higher orientation towards larvae than the control application. The orientation behavior displayed variations depending on the pesticide type and the EPN species involved. It is expected that this study will contribute to our understanding of the relationship between EPNs and pesticides, and ultimately enhancing the efficacy of EPNs.
Tribolium castaneum, Trogoderma granarium, Oryzaephilus surinamensis, Sitophilus oryzae, Rhyzopertha dominica, and Cryptolestes ferrugineus are all major pests of stored grains. In this study, the efficiency of single and joint applications of the entomopathogenic nematode (EPN) Steinernema carpocapsae at two different doses (50 and 100 IJs cm−2) and the entomopathogenic fungus (EPF) Beauveria bassiana for the management of the aforementioned pests was estimated. At single treatments, both doses of S. carpocapsae caused higher mortality rates to all six pest species compared to B. bassiana. The combined treatment of EPF and EPN resulted in higher mortality compared to single treatments. Mortality was strongly influenced by the exposure interval and the application dose of the EPN at both single and combined treatments. Maximum mortality was observed for the application of the combined treatment at the high dose of S. carpocapsae and B. bassiana. Among the different insect species tested, the maximum mortality rate was observed for R. dominica (96.62%), followed by S. oryzae (90.48%), T. castaneum (87.23%), C. ferrugineus (76.05%), O. surinamensis (70.74%), and T. granarium (57.71%). The outcomes of this study demonstrate the potential of utilizing specific combinations of EPF and EPN as effective natural enemies against stored-grain pests.
This study was designed to throw light on compatibility of entomopathogenic nematodes with certain soil amendments. Viability of infective juveniles (IJs) of Heterorhabditis bacteriophora (HP 88 strain), Steinernema carpocapsae (All strain) and S.riobravis in five concentrations of ammonium sulphate, urea, monosuperphosphate, trisuperphosphate and potassium sulphate was assessed under laboratory conditions. Results showed that IJs can tolerate short term exposure (24 hrs) to the recommended field rate of the tested fertilizers. Therefore, these fertilizers can be tank mixed and applied together with the nematodes. Moreover, the least harmful effect resulted from mixing chemical fertilizers with entomopathogenic nematodes was obtained with potassium sulphate followed by trisuperphosphate while ammonium sulphate showed median effect. However, the highest deleterious effect was obtained with monosuperphosphate and urea. Since, general means of IJs percent mortality in the recommended rate of these fertilizers one day after treatments were 1.6, 4.66, 4.77, 5.71 and 6.88, respectively. LT50 values were differed according to fertilizer, concentration and nematode species. S. riobravis was the superior nematode species survived in the tested fertilizers followed in most cases by S.carpocapsae while H.bacteriophora was least tolerant species.
Effects of field recommended rate of certain pesticides commonly used in Egypt and regularly applied to soil on viability and infectivity of the three nematode species were investigated under laboratory conditions. Results indicated that one day after treatment; the tested pesticides reduced activity of IJs by 18.10 to 39.26% depending on the pesticide and nematode species. When exposure time was increased beyond 24 hrs, IJs mortality was obviously increased to reach about 50% after the fourth day. Among the tested pesticides, nematicides were the most toxic ones. H.bacteriophora was more sensitive as compared to S.carpocapsae and S. riobravis. On the other hand, the interaction between these pesticides and nematodes against six instar larvae of Spodoptera littoralis Boisd. using co-toxicity factor bioassay showed that additive effect took place for most treatments, while synergism (potentiation) was detected in cases of dimethoate with H.bacteriophora and profenfos with H.bacteriophora and S.carpocapsae. However, antagonistic effect was determined in combinations of H.bacteriophora with all nematicides and herbicides except butachlor; S.carpocapsae with pendimethalin and S. riobravis with oxamyl.
Compatibility of three organic manures (i.e. compost, fresh manure and peat moss) with three entomopathogenic nematodes viz, H.bacteriophora, S. carpocapsae and S. riobravis was tested against the six larval instar of Spodoptera littoralis Biosd. under laboratory conditions in two types of sandy and clay soils. Data indicated that, one day after treatment, the tested organic manures were toxic to the entomopathogenic nematode species. When exposure time to organic manures increased beyond 24 hrs juvenile mortality increased to reach about 50% after the fourth day. Generally, it could be concluded that, H. bacteriophora is more sensitive to the tested organic fertilizers followed by S. carpocapsae and S. riobravis.
Entomopathogenic nematodes have shown potential as biocontrol agents targeting larvae of the annual bluegrass weevil, Listronotus maculicollis Kirby, a major golf course turf pest in eastern North America with widespread insecticide resistance. Control levels of single applications of nematodes have been too low and variable in the past to support application by golf course managers for weevil control. We examined if splitting nematode applications in two at half rates approximately 1 week apart as well as combinations of the nematodes with the neonicotinoid imidacloprid could improve nematode performance. In greenhouse experiments in pots with grass infested with ABW larvae, the entomopathogenic nematodes Steinernema carpocapsae, S. feltiae, and Heterorhabditis bacteriophora were similarly effective for larval control. Combination with imidacloprid resulted in additive weevil mortality. In a field experiment with natural infestations of larvae using 1.25 and 2.5 × 10⁹ nematodes ha⁻¹, respectively, of S. carpocapsae and H. bacteriophora, additive mortality in the combinations with imidacloprid amounted to 82% and 79% control, respectively, at the high nematode rate. In three additional field experiments using only S. carpocapsae, the low and high nematode rate provided on average 59% and 74% control, respectively, while their combinations with imidacloprid provided 75% and 84% control, respectively. Imidacloprid alone averaged 37% control. Mortality in all combination treatments was additive. Splitting S. carpocapsae applications provided a marginal increase in mortality that was significant only in one of three experiments. However, combining split applications with imidacloprid provided 88–95% control which could offer an effective alternative to synthetic insecticides.
Chemical insecticides are widely used to control soil pests but not always effective. Entomopathogenic nematodes (NEPs) are found in the soil and depend on host insects to complete their life cycle, and therefore have the potential to control soil pests. Thus, we aimed to investigate the possible joint use of these control methods by assessing the compatibility of two nematodes (Heterorhabditis amazonensis GL and Heterorhabditis amazonensis MC01) with five crop protection products used for maize seed treatment (Maxim®, Cruiser 350 FS®, Fortenza 600 FS®, Avicta 500 FS®, and Amulet®), as well as one neem-based product (NeenMax®). The experimental design was completely randomized with five replicates, six treatments, and one control, in which only distilled water was added to nematode suspension. Each replicate consisted of a test tube containing 1 mL suspension with 2,000 infective juveniles (IJs) and 1 mL of diluted product, following the manufacturer's recommendation. The evaluated parameters were viability, infectivity on Tenebrio molitor larvae and IJs production after exposure to products. Both nematodes were compatible with NeenMax® and Fortenza 600 FS® since they did not differ from the control and were classified as innocuous. Cruiser 350 FS ® was also compatible with the nematodes since the effect value of the product was lower than 30%. Amulet® was classified as slightly noxious, reducing H. amazonensis MC01 and H. amazonensis GL infectivity by 17.5% and 28.5%, and production by 18.2% and 22.3%, respectively. Despite not having reduced viability, Avicta 500 FS® and Maxim® were considered harmful. This is because Avicta 500 FS® and Maxim® reduced productivity by 70.0% and 72.5% and production by 66.1% and 65.4% for H. amazonensis MC01, respectively. For H. amazonensis MC01, both Avicta 500 FS® and Maxim® reduced infectivity by 76.19%, and production by 63.7% and 62.3%, respectively.
Cyclocephaline scarab beetles represent the second largest tribe of the subfamily Dynastinae, and the group includes the most speciose genus of dynastines, Cyclocephala . The period following publication of Sebő Endrődi’s The Dynastinae of the World has seen a huge increase in research interest on cyclocephalines, and much of this research has not been synthesized. The objective of this catalog and bibliography is to compile an exhaustive list of taxa in Cyclocephalini. This paper provides an updated foundation for understanding the taxonomy and classification of 14 genera and over 500 species in the tribe. It discusses the history of cataloging dynastine species, clarifies issues surrounding the neotype designations in Endrődi’s revision of Cyclocephalini, synthesizes all published distribution data for cyclocephaline species, and increases accessibility to the voluminous literature on the group by providing an easily searchable bibliography for each species. We propose the nomen novum Cyclocephalarogerpauli , new replacement name , for C.nigra Dechambre.
The cyclocephaline scarabs (Scarabaeidae: Dynastinae: Cyclocephalini) are a speciose tribe of beetles that include species that are ecologically and economically important as pollinators and pests of agriculture and turf. We provide an overview and synopsis of the 14 genera of Cyclocephalini that includes information on: 1) the taxonomic and nomenclatural history of the group; 2) diagnosis and identification of immature life-stages; 3) economic importance in agroecosystems; 4) natural enemies of these beetles; 5) use as food by humans; 6) the importance of adults as pollination mutualists; 7) fossil cyclocephalines and the evolution of the group; 8) generic-level identification of adults. We provide an expanded identification key to genera of world Cyclocephalini and diagnoses for each genus. Character illustrations and generic-level distribution maps are provided along with discussions on the relationships of the tribe’s genera.
Six entomopathogenic nematode species (EPNs) (Heterorhabditis bacteriophora H06 (H06), Steinernema carpocapsae NC116 (NC116), Steinernema carpocapsae All (All), Steinernema longicaudum X-7 (X-7), Steinernema feltiae SF-SN (Sf) and Heterorhabditis indica LN2 (LN2) were tested for virulence against 3rd instar Bradysia odoriphaga, and their interactions with thiamethoxam against 3rd instar B. odoriphaga under laboratory and greenhouse conditions were also evaluated. S. feltiae SF-SN, which is the most virulent, was selected to evaluate the synergism effects with thiamethoxam at different concentrations under laboratory conditions. S. feltiae SF-SN and thiamethoxam were either applied alone or in combination, and the combined application manner was evaluated in the greenhouse. Under laboratory conditions, a synergistic effect was found between six EPNs and thiamethoxam. The combination effects of Sf, All and LN2 species caused significantly higher mortality than the other three treatments (X-7, H06 and NC116). Furthermore, the combination of Sf and All species led to a significantly higher control effect than LN2 in greenhouse tests. In further greenhouse tests, the combination effect of Sf (0.75 billion IJs/ha) + thiamethoxam (1.0 kg a.i./ha) applied twice (28 day intervals) was significantly higher than a single treatment of Sf + thiamethoxam at twice the dosage. Compared to the single thiamethoxam application, the combination effects of Sf and thiamethoxam had the highest value at over 90% of the control effects for up to 6 weeks. Therefore, the integrated technique of the synergism of S. feltiae SF-SN species and thiamethoxam to control B. odoriphaga could be useful for integrated pest management in the future.
Following a request from EFSA, the Panel on Plant Protection Products and their Residues developed an opinion on the science behind the risk assessment of plant protection products for in-soil organisms. The current risk assessment scheme is reviewed, taking into account new regulatory frameworks and scientific developments. Proposals are made for specific protection goals for in-soil organisms being key drivers for relevant ecosystem services in agricultural landscapes such as nutrient cycling, soil structure, pest control and biodiversity. Considering the time-scales and biological processes related to the dispersal of the majority of in-soil organisms compared to terrestrial non-target arthropods living above soil, the Panel proposes that in-soil environmental risk assessments are made at in- and off-field scale considering field boundary levels. A new testing strategy which takes into account the relevant exposure routes for in-soil organisms and the potential direct and indirect effects is proposed. In order to address species recovery and long-term impacts of PPPs, the use of population models is also proposed.
Combinations of entomopathogenic nematodes Steinernema longicaudum X-7 and Heterorhabditis bacteriophora H06 with chlorantraniliprole, diflubenzuron, and imidacloprid insecticides at different rates for the control of the white grub, Holotrichia oblita Faldermann (Coleoptera: Scarabaeidae), were evaluated both in the laboratory and in peanut fields. In the laboratory, the combinations had a synergistic or additive effect on the second-instar larvae of H. oblita and caused faster mortality than one nematode species or insecticide alone. Heterorhabditis bacteriophora-chlorantraniliprole and H. bacteriophora-imidacloprid showed synergistic effects on the larvae. When higher concentrations of the insecticides were combined with nematodes, the stronger synergistic effects were found. In peanut fields, S. longicaudum-imidacloprid, H. bacteriophora-imidacloprid, or H. bacteriophora-chlorantraniliprole also showed synergistic effects against the larvae. The three nematode-insecticide combinations produced similar percentage reductions of the grub larvae and less percentages of injured legumes, compared with the chlorpyrifos treatment. Cost-benefit analysis showed that H. bacteriophora 5.0 × 10(3) infective juveniles (IJs) per plant (equal to 7.5 × 10(8) IJ ha(-1)) combined with imidacloprid at the recommended concentration is a practical strategy for the practitioner to manage the white grubs in the peanut production.
Entomopathogenic nematodes (EPN) have been used, especially against soil insect pests in Europe and U.S.A., for a decade. EPNs are feasible and attractive for biological control because of their effectiveness against various insect pests, host seeking ability, compatibility with standard equipment and long-term activity. In addition, EPNs can be applied simultaneously with some pesticides, which makes EPNs a potential biocontrol agent for integrated pest management. In the present study, the effects of 4 common pesticides (Glyphosate, Chlorpyrifos-ethyl, Captan, Fosetyl-al) on the virulence and mortality of EPN Sterinerma feltiae TUR-S3 were examined at 24 h and 48 h. According to the results, Fosetyl-al and Glyphosate showed the most negative impact on viability of TUR-S3, while Captan showed the most negative impact on virulence of the nematode. It is expected that the results of this study will provide useful information for future integrated pest management programs.
The present study aimed to evaluate the interactive applications of the promising biocontrol agents, the entomopathogenic nematodes (EPNs) Steinernema riobrave and Heterorhabditis bacteriophora and the entomopathogenic fungus (EPF) Beauveria bassiana, each at the LC25 level, to the last instars of the Egyptian cotton leafworm, Spodoptera littoralis, in either sequential or simultaneous fashion to determine whether interactions (synergistic, additive, or antagonistic) among these entomopathogens were present. Moreover, the indirect impact of two cultivated host plants (cabbage and cowpea) and three wild host plants (castor, Jew's mallow, and mallow) or their primary metabolites (total protein, carbohydrate, and lipid content) on the virulence of these entomopathogens and on nematode production also was assessed. Synergisms were observed among the different entomopathogen pairings. In case where sequential applications were made, applying the EPF first was best for infective juvenile (IJ) production; applying the EPN prior the EPF significantly reduced IJ production. Larvae raised on cabbage (the most lipid–rich diet) were most resistant for both EPN species tested. In general, not many IJs were produced from hosts that fed on mallow, but many were produced from hosts that fed on castor. In the case of EPF, B. bassiana was most effective at controlling larvae that fed on mallow, which was considered the least nutritive of the host plants. The results obtained are suggestive of an efficient control to S. littoralis. This would be achieved through the implementation of an integrated program including combining the entomopathogens studied with each other, or intercropping castor (in the case of the nematode application), or mallow (in the case of the fungus application) with cotton for enhancing the control of this insect pest in Egypt.
Several genera of grasses are capable of forming a mat of intertwined plants to form a solid ground cover with an extensive root mass. They can also regenerate from the crown after defoliation. The about 50 grass species amenable to use in turfgrass systems are further on able to form a high shoot density under the continuous mowing regimes characteristic for turfgrass systems (Christians, 1998). These properties allow turfgrasses to provide a hard–wearing permanent or semi–permanent ground cover that can be used for various recreational spaces in urban and suburban environments including lawns, parks, golf courses, and athletic fields. Other areas in which turfgrasses are grown include cemeteries, roadsides and sod farms. In the USA, turfgrass areas cover about 20 million ha and the size of the turfgrass industry is estimated at $40,000 million per year (National Turfgrass Federation, 2009). Besides their recreational uses, turfgrasses control soil erosion, capture and clean run–off water from urban areas, provide soil improvement and restoration, moderate temperature, reduce glare and noise, reduce pests, pollen and human disease exposure, create good wildlife habitats, and improve physical and mental health of urban populations (Beard & Green, 1994).
Entomopathogenic nematodes (EPN) of the genera Steinernema and Heterorhabditis are widely used in inundative biological pest control programmes. It has long been recognised that increased understanding of the ecology of EPN is important for better predictions of field performance and environmental risk (Ehlers & Hokkanen, 1996; Gaugler, Lewis, & Stuart, 1997). Increasingly, EPN are also finding a place as model organisms for fundamental studies in behavioural ecology and evolutionary biology (Campos-Herrera, Barbercheck, Hoy, & Stock, 2012). In this chapter, I consider the fate of EPN used in biocontrol, focussing largely on inundative application to soil. The aim is to provide an overview of the transformation of a biotechnological product to an ecological entity, rather than a review of this rather broad topic. There are already several extensive reviews relevant to the subject, including EPN behaviour and their fate in soil (e.g. Griffin, 2012; Kaya, 2002; Lewis, Campbell, Griffin, Kaya, & Peters, 2006; Stuart, Barbercheck, Grewal, Taylor, & Hoy, 2006; see also Chap. 4). It should be noted that, while the concept of this chapter is to follow the fate of commercially produced EPN when applied to soil, many of the laboratory studies cited have used nematodes produced in insects rather than taken from commercial formulations.
The current chapter reviews the most significant insect pests of soyabean and gives an overview of integrated pest management (IPM) theory and the consequences that can occur with greater frequency when IPM is not practised. The main tactics used in IPM is briefly reviewed and their potential and limitations for soyabean production is discussed. This chapter also includes an update of the recent invasion of the soyabean aphid (Aphis glycines) to North America and Australia from its native range in Asia and discusses how multiple tactics are employed to limit this economically important pest of soyabean.
This book documents and illustrates the major developments in the use of nematodes for biological control of insects and slugs. It has seven parts covering the morphology and taxonomy of all nematode groups used as biological control agents; entomopathogenic nematodes; entomophilic nematodes; slug-parasitic nematodes; predatory nematodes; fungal-feeding nematodes; and critical issues and research needs for future expansion of nematode use in biological control. Nematode biology, commercial production, formulation and quality control, application technology, strategy and safety are discussed. Separate chapters are devoted to the application of nematodes in different cropping systems and the efficacy of nematodes against specific pests such as plant parasitic nematodes and fungal pathogens.
Combinations of the anthranilic diamide, chlorantraniliprole, and the entomopathogenic nematode Heterorhabditis bacteriophora were tested for control of third-instar white grubs in turfgrass. In greenhouse experiments, the combinations had a synergistic or additive effect on the oriental beetle, Anomala (=Exomala) orientalis mortality, whether chlorantraniliprole was applied 1 week before H. bacteriophora or simultaneously. Combinations caused mortality to occur more rapidly than for the single agents. H. bacteriophora-chlorantraniliprole combinations had a synergistic effect on mortality of Japanese beetle, Popillia japonica, and northern masked chafer, Cyclocephala borealis, larvae in greenhouse experiments. Synergistic and additive effects on larval mortality were also observed in field experiments with A. orientalis and P. japonica. Across all experiments, synergistic interactions (based on a χ2 test) were observed in 64% of the combinations. Significant control (based on ANOVA) was observed in 12% of the chlorantraniliprole alone treatments and 29% of the H. bacteriophora alone treatments, but significant control occurred in 76% of the combination treatments. H. bacteriophora progeny production per dead larva recovered in greenhouse experiments did not differ between H. bacteriophora alone and the combination treatments. Nematode densities were higher at 28 days after treatment in soil from the combination treatments due to the higher number of larvae succumbing to nematode infection. H. bacteriophora and chlorantraniliprole were compatible in tank mixes. Agitation in solution with up to 900ppm chlorantraniliprole did not affect survival, infectivity, and reproduction of H. bacteriophora. H. bacteriophora-chlorantraniliprole combinations offer a safe and highly IPM compatible alternative for remedial white grub control.
During the past few years, white grubs have become recognized as a pest of southern highbush blueberries in California. White grubs feed on plant roots causing the plant to be stunted. In some cases, plant death has occurred when large grub populations attack newly planted fields. The predominant white grub species in California blueberries was identified as Cyclocephala longula. Research on flight characteristics determined that grubs are primarily in the third instar in April, pupate in May, and fly from mid-June through mid-July. Egg hatch begins in mid-July. Adult beetles begin flying about 30 min after dark and can be collected for a period of about 2 hours with black-light traps. Evaluation of control methods found that the entomopathogenic nematode Heterorhabditis bacteriophora and the insecticide imidacloprid can both provide control of the grub. Applications of Heterorhabditis bacteriophora on April 1 initially only provided 8.3% control, but resulted in secondary spread that led to an epizootic within the grub population. Applications of Heterorhabditis bacteriophora and imidacloprid in August resulted in 81.6 and 71.1% control, respectively, the following June.
Combining environmentally friendly insecticides with entomopathogenic nematodes may constitute an effective alternative to conventional chemical control of many insect pests. The objective of this laboratory study was to evaluate the effects of selected insecticides which are commonly used for pest control in vegetables in China on osmotically treated and untreated infective juveniles of Steinernema carpocapsae
strain All. The insecticides azadirachtin, chlorpyrifos,cypermethrin, fipronil, imidacloprid, malathion, thiamethoxam and chlorantraniliprole-thiamethoxam had no adverse effects on nematode survival and infectivity. In contrast, bisultap, emamectin benzoate, phoxim and rotenone proved harmful to S. carpocapsae All mainly by reducing infectivity of the infective juveniles to larvae of the greater wax moth,
Galleria mellonella. Osmotic induction is a promising way to induce entomopathogenic nematodes into partial anhydrobiosis and thus increase environmental stress tolerance of the nematodes as well as their shelf life after production. The present results showed that osmotic treatment did not adversely affect fitness of the nematode in terms of its susceptibility to insecticides and even increased its tolerance to chlorpyrifos and rotenone. The results of this laboratory study indicate that several of the tested insecticides can be
safely combined with S. carpocapsae All within an integrated pest management approach.
We present herein a review article of the latest developments of the biorational approaches in pest management appeared in the literature from 1997 to date. The proposed advantages of the biopesticides including their specificity, safety to non-target organisms, particularly mammals, and utilization in low, sometimes minute, amounts have led to an intensive research program by public and private institutions resulting in an avalanche of reports in attempts to discover and develop newer and safer pesticides, particularly in the past three decades. This review is divided into three main chapters, including microbial insecticides in pest control, utilization of semiochemicals, and botanical insecticides, paying particular attention to those practical approaches that are respectful to the environment.
An investigation was carried out to determine whether new neonicotinoid-nematode combinations and earlier applications against younger larval stages could increase the efficacy of synergistic neonicotinoid-entomopathogenic nematode combinations against white grubs.
In the laboratory, combinations of the neonicotinoids imidacloprid and clothianidin and the nematodes Heterorhabditis bacteriophora Poinar and H. zealandica Poinar against third instars were compared. In Anomala orientalis (Waterhouse) and Popillia japonica Newman, H. bacteriophora-imidacloprid combinations showed the most consistent synergism but did not cause significantly higher mortality than H. zealandica-imidacloprid combinations. In Cyclocephala borealis Arrow, there was no clear trend as to which combinations caused the most consistent synergism, but H. zealandica-imidacloprid combinations tended to cause the highest mortalities. In the laboratory, imidacloprid-H. bacteriophora combinations provided more consistent synergism against third-instar than against second-instar A. orientalis, but mortality was higher in second instars. In field experiments, imidacloprid-H. bacteriophora combinations against A. orientalis and P. japonica provided more consistent synergism when applied in mid-September but more consistent control when applied in late August.
Imidacloprid is a better synergist for entomopathogenic nematodes than clothianidin. Imidacloprid-nematode combinations are more effective against second instars than against third instars, allowing rate reductions of both agents to make this approach more competitive with full-rate applications of neonicotinoid alone.
Grubs of the scarabaeid Cyclocephala hirta infected with the milky disease bacterium, Bacillus popilliae (Bp), were more susceptible to the entomopathogenic nematodes Heterorhabditis bacteriophora and Steinernema glaseri than healthy grubs. Increased susceptibility was due to greater ease of nematode penetration through the midguts of Bp-infected insects and occurred after > 10 days exposure to B. popilliae spores. By that time, the bacterium was proliferating rapidly in the insect hemolymph and possibly stressed the insect by physiological starvation. Attraction of the nematodes to the insects and cuticular penetration by the nematodes were ruled out as possible reasons for the enhanced susceptibility of Bp-infected grubs. In greenhouse pot trials, S. glaseri killed more Bp-infected grubs than healthy grubs, whereas no differences were noted with H. bacteriophora. Thus, to achieve the best grub control in the presence of B. popilliae, application of S. glaseri is recommended. The compatibility of B. popilliae and entomopathogenic nematodes in the field is ensured by the existence of a diseased insect class with a low level of susceptibility to the nematode, the presence of B. popilliae in grubs not interfering with nematode progeny production, and the ability of B. popilliae spores to survive invading nematodes and their associated bacteria.
In an examination of entomopathogenic nematodes used in inundative releases on turfgrass against Japanese beetle larvae, Popillia japonica Newman, 380 treatments from 82 field trials performed from 1984 to 1988 were analyzed using a standard protocol. The results show that most test failures can be explained on the basis of unsuitable nematode strains or environmental conditions. Steinemema carpocapsae (Weiser) appears ill-adapted to parasitize Japanese beetle larvae under any range of conditions. By contrast, theHP88strain of Heterorhabditis bacteriophora Poinar, produced on solid media, provides control comparable with that by chemical insecticides at the appropriate season (fall), soil temperature ( >200 <:), soil type (silty clay), irrigation frequency (1-4-d intervals), and thatch depth «10mm). The importance of multiple tests that can be analyzed is discussed. Standardized procedures are recommended for field testing; if widely adopted, they would permit comparisons between trials and the generation of large data sets needed for developing statistical models.
Imidacloprid, a chloronicotinyl, and halofenozide, a bisacylhydrazine ecdysteroid agonist, recently have become widely used for residual control of scarabaeid grubs in turf. We evaluated their impact on earthworms and beneficial arthropods in field trials, and tested whether application in late spring might interfere with subsequent predation on black cutworm, Agrotis ipsilon (Hufnagel), and Japanese beetle, Popillia japonica Newman, life stages in Kentucky bluegrass, Poa pratensis L., turf. Bendiocarb, a short-residual carbamate, was included for comparison. Imidacloprid caused some short-term suppression of earthworms, whereas bendiocarb had severe impact on earthworms, mesostigmatid mites, and Collembola. Pitfall trap captures of predatory coleopteran larvae and hister beetles were reduced by imidacloprid and bendiocarb, but abundance of ants, carabids, spiders, and staphylinids was largely unaffected. Halofenozide caused no reduction in abundance of any group of beneficial invertebrates. Scavenging on fresh-frozen A. ipsilon larvae was reduced for ≈1 wk after use of imidacloprid or bendiocarb, but predation rates on eggs or pupae of A. ipsilon, and on implanted P. japonica eggs, were unaffected. This work suggests that application of halofenozide or imidacloprid, followed by irrigation, will have relatively little impact on beneficial invertebrates, although both compounds are persistent enough to control P. japonica and Cyclocephala spp. grubs eclosing several months later.
In previous greenhouse studies, the insecticide imidacloprid and the entomopathogenic nematode Heterorhabditis bacteriophora Poinar interacted synergistically against third instars of the masked chafers Cyclocephala hirta LeConte and C. pasadenae Casey (Coleoptera: Scarabaeidae). We tested this interaction for two additional nematode species and three additional scarab species under field conditions. In greenhouse tests, H. bacteriophora and Steinernema glaseri (Steiner) interacted synergistically against third instars of the Japanese beetle, Popillia japonica Newman, the oriental beetle, Exomala orientalis Waterhouse, and the masked chafers Cyclocephala borealis Arrow, C. pasadenae, and C. hirta. The degree of interaction varied with nematode species. The strongest synergism occurred between imidacloprid and S. glaseri. Synergism between imidacloprid and H. bacteriophora was weaker and the interaction was not always significant. Combinations of imidacloprid and S. kushidai Mamiya only resulted in additive mortality. The synergistic interaction was also observed in field trials but the results were more variable than those under greenhouse conditions. The combination of nematodes and imidacloprid could be used for curative treatments of white grub infestations, especially against scarab species that are less susceptible to nematodes and/or imidacloprid. This combination has a low environmental impact and high compatibility with natural biological control of turfgrass insects. The possible roles of these combinations in augmentative control approaches are discussed.
Il est décrit une méthode d'estimation des larves infestantes de nématodes entomopathogènes présentes dans des échantillons de sol, méthode basée sur des échantillonnages répétés des larves de #Galleria mellonella$ jouant le rôle d'appât. L'efficacité d'extraction de cette méthode est très élevée et elle apparaît beaucoup plus rapide que les autres méthodes en usage. Dix larves sont placées dans chaque échantillon et sont régulièrement remplacées par de nouveaux insectes jusqu'à ce que l'infestation par les nématodes cesse. L'estimation de la densité des nématodes est basée sur une relation linéaire forte entre le log10 du nombre de larves infestées par les nématodes et le log10 du nombre de nématodes retrouvés dans ces larves. Cette relation a été calculée pour deux espèces de nématodes dans des échantillons provenant du champ (populations naturelles) et en laboratoire pour trois espèces de nématodes et trois types de sol. La pente de la courbe de régression linéaire ne présente qu'une faible variation entre essais, espèces et types de sol. (Résumé d'auteur)
The effects of inundative releases of entomopathogenic Steinernema carpocapsae and S. feltiae infective juveniles and applications of the biological control fungus Trichoderma harzianum T-22 (RootShield) on Pratylenchus penetrans and strawberry black root rot caused by Rhizoctonia fragariae were determined in field microplots and small plots. Entomopathogenic nematodes were applied as a soil drench at rates of 7.4 or 14.8 billion per ha in May or August for 3 years. RootShield was applied as crown dips at planting or later as a soil drench. There were no differences in P. penetrans from plants drenched with water alone or with S. carpocapsae or S. feltiae nematodes, averaged over rates and timing. The nematode species applied and the rate or timing of application had no effect on lesion nematodes. Our results suggest that P. penetrans exposure to living or heat-killed S. feltiae and associated bacteria resulted in temporary lack of motility. A progressively increasing proportion of P. penetrans became active again and, after 8 days, had infected tomato roots in similar numbers to unexposed P. penetrans. In laboratory assays and field plots or microplots, S. carpocapsae and S. feltiae did not permanently affect P. penetrans in tomato or strawberry.
Publisher Summary
This chapter focuses on the techniques used for identifying, isolating, propagating, assaying, and preserving nematodes that are parasitic in or pathogenic to insects. Nematodes are nonsegmented animals with excretory, nervous, digestive, reproductive, and muscular systems but lacking circulatory and respiratory systems. The stage of entomogenous and entomopathogenic nematodes that is infective varies depending on the group. A good stereomicroscope is essential for nematode identification and should have a range of magnification between 10 and 100X, a fairly fiat field, and good resolution. The gonads and other structures of fixed nematodes may be obscured by the granular appearance of the intestine. Specimens can be cleared by processing to lactophenol or glycerin. The cephalic structures and the number of longitudinal chords are diagnostic characters for genetic or specific determination of certain groups of nematodes. Extraction methods for insect nematodes are derived from techniques developed with plant-parasitic nematodes. It is found that the most common methods are the Baermann funnel, sieving, elutriation, and centrifugal flotation.
The well-respected center of insect nematology at CSIRO, Canberra, Australia, presents a well-organized book of review papers based on two symposia held at the XIX International Congress of Entomology in Beijing, China, in July 1992. There are 18 chapters, wlitten by 23 authors, on various groups of insect-parasitic nematodes. The book begins with a preface written by tbe editors and ends with a workable index.
Field tests were conducted in 1986 and 1987 to evaluate control of Japanese beetle larvae, Popillia japonica Newman, in turfgrass plots by heterorhabditid and steinemematid nematodes. Heterorhabditis bacteriophora Poinar (NC strain) reduced populations a maximum of60%, 34 d after a fall 1986 treatment. Control increased to 96% before pupation the following spring, and was 93-99% of the next larval generation. Application of Steinemema (=Neoaplectana) carpocapsae Weiser (All strain) provided a maximum of 51% control after 34 d, 90% the next spring (290 d after treatment), and 0% after 386 d. A spring 1987 application of H. bacteriophora resulted in 68% control 28 d after treatment, and up to 67% of the following generation of] apanese beetle larvae in the fall (138 dafter treatment). H. bacteriophora (HP88 strain) gave 100% control after 28 d in the spring of 1987, and 93-97% control of the next generation of larvae. No adverse effects on nontarget organisms (mites or collembola) were observed 28 d after treatments with any of the nematodes. Our data show that nematodes reproduce in Japanese beetle larvae, survive in the field in turfgrass, and have an influence on target hosts for a longer period oftime than previously demonstrated.
Combinations of the insecticide imidacloprid and entomopathogenic nematodes were tested for control of white grubs. In greenhouse tests, field-collected 3rd-instar white grubs were placed in pots with grass treated with imidacloprid, the entomopathogenic nematode Heterorhabditis bacteriophora (Poinar), or both. Combinations of imidacloprid and nematodes had a strong synergistic effect on mortality at imidacloprid concentrations ranging between 50 to 200 g (AI) / ha. This effect was observed when imidacloprid and the nematodes were applied at the same time or when imidacloprid was applied first followed by the nematodes 14 d later. The synergistic interaction occurred against a nematode-susceptible scarab species, Cyclocephala hirta LeConte, and against a more nematode-resistant scarab species, C. pasadenae Casey. When infective juveniles of H. bacteriophora were agitated in solutions of imidacloprid for 24 h, no negative effect on their survival and infectivity was observed.
In previous laboratory studies, entomopathogenic nematodes andBacillus thuringiensissubspeciesjaponensis(Btj) caused additive or synergistic mortality in third-instarCyclocephala(Coleoptera: Scarabaeidae) grubs when the nematodes were applied at least 7 days afterBtj.This type of mortality was observed forC. hirta,a species that is not very susceptible toBtj,and forC. pasadenae,a species that has intermediate susceptibility toBtj.In the present study, this observation was confirmed for third-instarAnomala orientalis,a species that is highly susceptible toBtj.In greenhouse and field studies, additive or synergistic interactions between nematodes andBtjwere observed for all three scarab species. The interactions were variable, and to achieve acceptable grub control, high concentrations ofBtjhad to be applied. A subsequent greenhouse experiment showed that young third-instarC. pasadenaewere more susceptible toBtjthan older third instars. In addition the interaction between nematodes andBtjwas also more synergistic in the younger than in the older third instars. In a field test against a population ofC. hirtaconsisting of late second and early third instars, combinations of nematodes andBtjat economic application rates provided acceptable control levels whether applied simultaneously or with a 4-day delay betweenBtjand nematode application. Our observations suggest that curative control of white grubs is possible with combinations of entomopathogenic nematodes andBtjif the applications are done when populations consist of second and early third instars.
The mode of action of the nitromethylene heterocycle group of insecticides was investigated in the American cockroach, Periplaneta americana. In vivo symptomology was characterized by a definite sequence of events, starting with abdominal quivering and followed, in order, by wing flexing, uncontrollable preening, leg tremors, violent whole body shaking, prostration, and death. Neurophysiological experiments showed that the nitromethylene heterocycles have dramatic effects on nerve impulse transmission at the cholinergic cercal nerve-giant fiber synapses located within the cockroach sixth abdominal ganglion. The effects were biphasic and were characterized by an initial increase in the frequency of spontaneous giant fiber discharges, followed by the development of a complete block to nerve impulse propagation. The nitromethylene heterocycles did not inhibit insect cholinesterase. Neuropharmacological experiments showed that the specific site of action was postsynaptic, and probably involved an agonistic effect on postsynaptic acetylcholine receptors.
In previous greenhouse and field studies, the neonicotinoid insecticide imidacloprid and the entomopathogenic nematodes Heterorhabditis bacteriophora and Steinernema glaseri interacted synergistically against third-instars of the Japanese beetle, Popillia japonica, the oriental beetle, Exomala (=Anomala) orientalis, and three masked chafer species, Cyclocephala hirta, C. pasadenae, and C. borealis (Coleoptera: Scarabaeidae). We tested whether this interaction would also occur with other neonicotinoids, primarily thiamethoxam. In laboratory, greenhouse and field experiments, imidacloprid provided stronger and more consistent synergism with nematodes than thiamethoxam. White grub mortality resulting from nematode–neonicotinoid combinations was synergistic/additive/antagonistic in 75/25/0% of our observations with imidacloprid and 37/42/21% of our observations with thiamethoxam. Neonicotinoid–nematode interactions varied with white grub species. Imidacloprid always interacted synergistically with nematodes against E. orientalis and P. japonica, whereas no enhancement occurred against Rhizotrogus majalis and Maladera castanea. Against E. orientalis, imidacloprid interacted synergistically with five nematode species, H. bacteriophora, H. megidis, H. marelatus, S. glaseri, and S. feltiae. Synergistic combinations of nematodes and a neonicotinoid insecticide could be used for curative treatments of white grub infestations, especially against E. orientalis and P. japonica. This combination may allow spot-treatment of turf areas that exceed damage thresholds, thereby limiting the environmental impact of the insecticide application.
We studied the interactions betweenBacillus thuringiensissubspeciesjaponensisBuibui strain (Btj) and entomopathogenic nematodes on the white grubs,Cyclocephala hirtaandC. pasadenae.Field-collected third instar grubs were kept individually in microcosms filled with soil and fed grass seeds. Grubs were exposed to various concentrations ofBtjand/or entomopathogenic nematodes and grub mortality was assessed at weekly intervals. Nematodes were added at 0 to 14 days after application ofBtj.Throughout most of our experiments, combinations ofBtjand nematodes caused additive grub mortalities or greater than additive mortalities, indicating synergism. To achieve additive or synergistic effects, grubs had to be exposed toBtjfor at least 7 days before the addition of nematodes. We observed this interaction betweenBtjandHeterorhabditis bacteriophoraorSteinernema glaseri,but not with the most pathogenic nematode,S. kushidai.The additive or synergistic interaction betweenBtjandS. glaseriorH. bacteriophoramay offer a powerful and reliable tool for scarab grub control.
Entomopathogenic nematodes and the chloronicotinyl insecticide, imidacloprid, interact synergistically on the mortality of third-instar white grubs (Coleoptera: Scarabaeidae). The degree of interaction, however, varies with nematode species, being synergistic for Steinernema glaseri (Steiner) and Heterorhabditis bacteriophora Poinar, but only additive for Steinernema kushidai Mamiya. The mechanism of the interaction between imidacloprid and these three entomopathogenic nematodes was studied in the laboratory. In vials with soil and grass, mortality, speed of kill, and nematode establishment were negatively affected by imidacloprid with S. kushidai but positively affected with S. glaseri and H. bacteriophora. In all other experiments, imidacloprid had a similar effect for all three nematode species on various factors important for the successful nematode infection in white grubs. Nematode attraction to grubs was not affected by imidacloprid treatment of the grubs. Establishment of intra-hemocoelically injected nematodes was always higher in imidacloprid-treated grubs but the differences were small and in most cases not significant. The major factor responsible for synergistic interactions between imidacloprid and entomopathogenic nematodes appears to be the general disruption of normal nerve function due to imidacloprid resulting in drastically reduced activity of the grubs. This sluggishness facilitates host attachment of infective juvenile nematodes. Grooming and evasive behavior in response to nematode attack was also reduced in imidacloprid-treated grubs. The degree to which different white grub species responded to entomopathogenic nematode attack varied considerably. Untreated Popillia japonica Newman (Coleoptera: Scarabaeidae) grubs were the most responsive to nematode attack among the species tested. Untreated Cyclocephala borealis Arrow (Coleoptera: Scarabaeidae) grubs showed a weaker grooming and no evasion response, and untreated C. hirta LeConte (Coleoptera: Scarabaeidae) grubs showed no significant response. Chewing/biting behavior was significantly increased in the presence of nematodes in untreated P. japonica and C. borealis but not in C. hirta and imidacloprid-treated P. japonica and C. borealis. Our observations, however, did not provide an explanation for the lack of synergism between imidacloprid and S. kushidai.
Routes by which nontarget predatory insects can be exposed to turfgrass pesticides include topical, residual, and dietary exposure. We used each of these routes to evaluate potential lethal or sublethal effects of two novel turfgrass insecticides, imidacloprid and halofenozide, and a carbamate, bendiocarb, on survival, behavior, and fecundity of the ground beetle Harpalus pennsylvanicus DeGeer. Field-collected carabids were exposed to direct spray applications in turf plots, fed food contaminated by such applications, or exposed to irrigated or nonirrigated residues on turf cores. Halofenozide caused no apparent acute, adverse effects through topical, residual, or dietary exposure. Moreover, the viability of eggs laid by females fed halofenozide-treated food once, or continuously for 30 d, was not reduced. In contrast, topical or dietary exposure of carabids to bendiocarb inevitably was lethal. Exposure to imidacloprid by those routes caused high incidence of sublethal, neurotoxic effects including paralysis, impaired walking, and excessive grooming. Intoxicated beetles usually recovered within a few days in the laboratory, but in the field, they were shown to be highly vulnerable to predation by ants. One-time intoxication by imidacloprid did not reduce females' fecundity or viability of eggs. There was no apparent behavioral avoidance of insecticide residues, or of insecticide-treated food. Carabids exposed to dry residues on turfgrass cores suffered high mortality from bendiocarb, and some intoxication from imidacloprid, but these effects were greatly reduced by posttreatment irrigation. Implications for predicting hazards of insecticides to beneficial invertebrates in turfgrass are discussed.
Imidacloprid – a new systemic insecticide
- Elbert A B Becker
- Hartwig
Elbert A, Becker B, Hartwig J & Erdelen C (1991) Imidacloprid – a new systemic insecticide. Pflanzenschutz-Nachrichten Bayer 44: 113 –136.
Destructive Turfgrass Insects: Biology, Diagnosis, and Control SAS Institute (1996) SAS 6.11 for Windows. SAS Institute, Cary. Schroeder ME & Flattum RF (1984) The mode of action and neurotoxic properties of the nitromethylene heterocycle insecticides
- Potter
- Da
Potter DA (1998) Destructive Turfgrass Insects: Biology, Diagnosis, and Control. Ann Arbor Press, Chelsea. SAS Institute (1996) SAS 6.11 for Windows. SAS Institute, Cary. Schroeder ME & Flattum RF (1984) The mode of action and neurotoxic properties of the nitromethylene heterocycle insecticides. Pesticide Biochemistry and Physiology 2: 148 –160.
Imidacloprid – a new systemic insecticide
- Elbert A
- Koppenhöfer
The mode of action and neurotoxic properties of the nitromethylene heterocycle insecticides
- Schroeder