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Symptoms of Botryosphaeriaceae species affecting almond cv. Nonpareil: growth crack through which the pathogen infected the wood (A) and typical trunk gumming (B); blighted fruit (C) leading to canker formation (D).
Source publication
In recent decades, the cultivated area and production of nuts and olives have increased, driven by an increasing consumer interest in healthier food. Diseases of almond, pistachio, olive, and walnut crops caused by species belonging to the Botryosphaeriaceae family have caused concern worldwide. Although considerable progress has been made in eluci...
Contexts in source publication
Context 1
... A canker disease of almond trunk and scaffold branches caused by B. dothidea was described in California in the mid-1950s (English 1975). The pathogen kills the bark of almonds, causing a canker that expands horizontally in the tree trunk, forming a band that appears recessed (English 1975;Inderbitzin et al. 2010; Fig. 3A-B), resulting in the common name "band canker." Infection occurs through natural growth cracks in the bark caused by trunk growth. For this reason, symptoms often appear in 3-to 5-year-old trees on vigorous hybrid rootstocks. The pathogen, initially identified as B. dothidea, was reported to cause cankers of branches, shoots, and twigs ...
Context 2
... and gradual decline. Infection by Botryosphaeriaceae species can often cause the loss of the tree when the canker encircles the trunk. Moreover, severely affected trees are subject to breakage due to wind or harvesting. More rarely, cankers are formed in areas of the branches that bear nuts causing the blight of fruit with or without gumming (Fig. ...
Context 3
... presence of wounds facilitates infection, and severe symptoms are often associated with different types of wounds on lignified and green tissues (Michailides 1991;Michailides and Morgan 2004;Moral et al. 2017b). In almond band canker, plant infection occurs through growth cracks that serve as entryways of infection (Fig. 3A). Almond infection can also occur through wounds on fruit and peduncles as well as cracks at the base of shoots and scaffold branches due to wind damage and pruning wounds. Aggressive cankers are often initiated from major pruning cuts and can ultimately kill trees. Wounding caused by Hemipteran insects exacerbates fruit infection, ...
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Citations
... Moreover, Botryosphaeriaceae and Diaporthe spp. are reported to infect plants mainly through natural openings or wounds [108,109]. Different cultural practices, such as pruning and fruit thinning, could cause wounds on plants, thus favoring the entry of these pathogens and subsequent development of dieback and stem-end rot. Optimal management of orchards and the protection of wound cuts is recommended to avoid the spread of these pathogens. ...
Florida ranks among the most important citrus growing regions in the USA. The present study investigates the occurrence, diversity, and pathogenicity of fungal species associated with symptomatic sweet orange (Citrus sinensis) cv. Valencia plants and fruit. The survey was conducted on twigs and fruit collected in Southwest Florida during 2022. Based on morphological and molecular characteristics, the identified isolates belonged to the species Lasiodiplodia iraniensis, Diaporthe pseudomangiferae, and Diaporthe ueckerae. The pathogenicity of representative isolates was evaluated on citrus fruit and plants. Lasiodiplodia iraniensis was the most virulent on fruit and plants, followed by Diaporthe pseudomangiferae. Diaporthe ueckerae had the lowest virulence on fruit, and it was not pathogenic to plants. In vitro tests were performed to assess the effect of temperature on mycelial radial growth. The optimum temperature of growth ranged from 26.0 to 28.4 °C for all the evaluated species, and L. iraniensis showed the fastest mycelial growth. This study represents the first report of L. iraniensis as a causal agent of tree dieback and fruit stem-end rot on C. sinensis worldwide. Moreover, D. pseudomangiferae and D. ueckerae are reported here for the first time in association with citrus diseases worldwide.
... Conidia of A. decipiens are thought to be dispersed through wind and rains as those of Botryosphaeriaceae and Diaporthe spp., representing a primary source of inoculum (Phillips et al. 2013;Lawrence et al. 2015). Pruning wounds, along with natural openings, are the main pathway for the colonization (Moral et al. 2019). The use of noncontaminated tools, the protection of wounds and the removal of pruning debris must be adopted. ...
Italy is the second largest hazelnut producer worldwide and Piedmont is one of the most productive regions in the country. The changing climatic condition and fungal trunk diseases (FTD) can have a severe impact on this crop. Particularly, the considerable spread of Cytospora cankers (‘Mal dello stacco’) and dieback represent a serious concern for producers. Thus, considering the limited studies on the causal agents, different surveys were conducted in seven hazelnut orchards during 2021 and 2022. Eight fungal species were identified: Anthostoma decipiens, Botryosphaeria dothidea, Diaporthe eres, Dia. rudis, Diplodia seriata, Dip. subglobosa, Dothiorella parva and Nothophoma brennandiae . Species identification was achieved through multilocus phylogeny and morphology assessment. All the fungal species were pathogenic on healthy hazelnut plants (cultivar Tonda Gentile) and A. decipiens and Dia. eres were the most aggressive. The present study is the first report of B. dothidea and Dia. eres as causal agents of FTD on hazelnut in Italy and of Dia. rudis, Dip. subglobosa and N. brennandiae worldwide. Moreover, the study provides clarification of the fungal pathogens associated with FTD on this crop in Piedmont, thus laying the base for further studies on epidemiology, ecology and management strategies.
... Diseases caused by Botryosphaeriaceae can be mono-or oligo-cyclic (undergoing two to three infection cycles per season), and epidemic events may occur for subsequent years, resulting in high economic losses. These fungi can also spread from nurseries to open fields as latent infections (Moral et al., 2019). ...
Many fungi belonging to Botryosphaeriaceae are well-known as causal agents of diseases in economically and ecologically important agricultural crops and forest trees. In Italy, the high diffusion of Botryosphaeriaceae infections observed over the last decade, has shown the importance of this group of fungi, which are becoming limiting factors for plant production in agricultural systems, nurseries and natural and urban landscapes. Global warming and stress factors such as occasional extreme climatic events can affect the susceptibility of host plants, as well as fungus behaviour, increasing the risk of future infections. Available reports of Botryosphaeriaceae in Italy have been examined, focusing on wood and fruit pathogens, resulting in a list of ten genera and 57 species. Diplodia is the most widespread genus in Italy with 76 records on 44 hosts, while at species level, Neofusicoccum parvum, Botryosphaeria dothidea and Diplodia seriata show the widest host ranges and many records. The ability of the pathogens to remain latent on asymptomatic plants, and uncontrolled trade of plant materials among countries, facilitate the dissemination and potential introduction of new Botryosphaeriaceae species. Preventive detection and adequate control strategies are always needed to limit the potential damage caused by Botryosphaeriaceae. This review had particular emphasis on host-pathogen associations, disease symptoms, geographic distribution, metabolite production, and accurate pathogen identification.
... This scenario, coupled with the ongoing impact of climate change, is increasing the incidence of canker diseases in almond. (Fernández et al. 2023;Moral et al. 2019;Velásquez et al. 2018). Latent infection in asymptomatic nursery stock and trees in the field makes effective control measures more difficult. ...
BACKGROUND
Botryosphaeria dieback is a canker disease caused by fungal species of the Botryosphaeriaceae family that threatens almond productivity. The most common control measure to prevent canker development is the application of fungicides which are being phased out by European Union regulations. In the present study, two sets of bacterial strains were evaluated for their antifungal activity against pathogenic Botryosphaeriaceae species through in vitro and in vivo antagonism assays.
RESULTS
The rhizospheric bacteria Pseudomonas aeruginosa AC17 and Bacillus velezensis ACH16, as well as the endophytic bacteria Bacillus mobilis Sol 1–2, respectively inhibited 87, 95, and 63% of the mycelial growth of Neofusicoccum parvum, Botryosphaeria dothidea, Diplodia seriata, and Macrophomina phaseolina. Additionally, they significantly reduced the length of lesions caused by N. parvum and B. dothidea in artificially inoculated detached almond twigs. All these bacterial strains produce hydrolytic enzymes that are able to degrade the fungal cell wall. P. aeruginosa AC17 also produces toxic volatile compounds, such as hydrogen cyanide. This strain was the most effective in controlling Botryosphaeria dieback in planta under controlled conditions at a level similar to the biocontrol agent Trichoderma atroviride and standard chemical fungicide treatments.
CONCLUSION
Pseudomonas aeruginosa AC17 is the best candidate to be considered as a potential biocontrol agent against Botryosphaeriaceae fungi affecting almond. © 2023 Society of Chemical Industry.
... Symptoms are observable on most parts of the walnut tree as growing brown patches and the disease results in rot on the end of the husks (Belisario et al., 2008;Pollegioni et al., 2010), hence causing premature fruit drop and has an effect on the quality of the kernel as well (Holb et al., 2002). Nut crops are more infected by fungal pathogens in recent years, and the damage affects not the woody plant parts only but the kernels, as well (Chen et al., 2014;Michailides and Morgan, 2016;Moral et al., 2019). Botryosphaeria spp. ...
... Bud monitoring (BUDMON) is a technique that can be used to estimate the current infestation of an orchard, as overwintered pathogens can initiate early infections (Moral et al., 2019). In early March, culturable microbiome of buds was surveyed in the Jánkmajtis growing area, to determine disease risk and identify the time and the potential ways of the infection routes. ...
... Both pathogens could be detected in green walnuts with ONFIT method in high proportion from symptomatic samples. This method is suitable for the detection of latent infection, providing data for the farmers in decision-making for disease management actions (Moral et al., 2019). In addition to careful hygiene and proper horticultural techniques, it is important to schedule the spraying, including early spring infection, as pathogens could be detected in asymptomatic buds (catkins) and to pay special attention to avoid scars and wounds which may initiate the secondary, latent infection of these pathogens. ...
The acreage of English walnut ( Juglans regia L.) is constantly expanding in Hungary, due to the favorable climatic conditions and economic importance. Last years, serious damage was reported from several orchards with high percentage of rotted, moldy kernels. The aim of this research was to identify the pathogens at different growth stages. Fungi were cultured from the spotty, shriveled and rotted kernels, and monosporic isolates were identified based on morphological characters and molecular markers (ITS region and tef1 locus sequences). Botryosphaeria dothidea and Diaporthe eres were identified in high proportion from symptomatic kernels. These species were also isolated from different parts of walnut trees in different seasons. D. eres was detected in a high proportion from asymptomatic buds in March, while the presence of both species was observed in symptomatic husks with Overnight Freezing-Incubation Technique (ONFIT) in June. Their optimal growth temperature defined to be between 20–25 °C, and the growth of D. eres isolates was completely inhibited at 35 °C.
... International competition and imports of fruits and nuts from outside of Europe, such as walnuts from California, changes of land use to artificial areas as well as political measures in favour of more standardised means of production, have also been linked to a decline of permanent crop agroforestry across the EU (Eichhorn et al., 2006). Fungal diseases caused by species in the Botryosphaeriaceae family have also reduced the production of nut crops (such as almond, pistachio and walnut), and olives (Moral et al., 2019). ...
Agroforestry integrates woody vegetation with crop and/or livestock production to benefit from the ecological and economic interactions. The objective of this paper is to systematically determine the spatial distribution of agroforestry in the EU, and changes in the areas and types of agroforestry from 2009 to 2018. This was achieved using the Land Use/Cover Area Statistical (LUCAS) dataset. Agroforestry was categorised into silvopastoral, silvoarable, agrosilvopastoral, grazed permanent crops, intercropped permanent crops and kitchen gardens systems. In our categorisation of ‘agroforestry’, sites combing trees and shrubs with understorey grass or forage were required to show evidence of grazing. In 2018, the total area of agroforestry in the EU28 was 114,621 km² equivalent to 6.4% of the utilised agricultural area (UAA), and a majority located in the Mediterranean bioregion. Silvopastoral was the most widespread system, representing 81% of the total agroforestry area (5% of UAA), with almost a third of that area present in Spain. An initial analysis of the LUCAS data suggested that the area of agroforestry increased from 2009 to 2012, before declining from 2012 to 2018. However our subsequent analysis suggests that the area of agroforestry in 2009 was underestimated due to a mis-categorisation of some grazing areas. After making corrections, we calculated that the area of agroforestry (using the above definitions) in the EU23 (a full-time sequence for the EU28 is unavailable) declined by 47% between 2009 and 2018. This decline is primarily due to a reduction in outdoor grazing, perhaps driven by reduced livestock numbers and/or permanent livestock housing. The only agroforestry system showing an increase was kitchen gardens (7%). The paper highlights the usefulness of the LUCAS dataset for studying the extent of agroforestry in Europe, but also potential limitations in terms of the consistency of the location of data points and the categorisation of grazing. The paper also argues that although the area of within-field agroforestry may be declining, the drive towards net zero greenhouse gas emissions may be re-establishing the link between increased tree cover and food production at a farm-level.
... For example, in Spain, olives and almonds are first and second in acreage among crops (López- Moral et al., 2017). Almonds are cultivated in the USA, Australia, and Spain (Moral et al., 2019), and olives are grown in the Mediterranean region (Rallo et al., 2018), particularly Spain, Italy, and Greece, and in Argentina, where olive groves cover >110,000 ha (Torres et al., 2017). However, >100 pests and pathogens threaten almond and olive cultivation (Fernández-Escobar et al., 2013). ...
... Botryosphaeriaceae and Diaporthe are widespread worldwide fungi associated with canker diseases in a broad diversity of woody crops (Gomes et al. 2013;Phillips et al. 2008Phillips et al. , 2013Phillips et al. , 2019. On English walnut (Juglans regia L.), which is a tree nut of a major economic importance in China, the United States, and several Mediterranean countries (e.g., France and Spain) (FAO 2019;INC 2017;L opez-Larrinaga et al. 2017), Botryosphaeriaceae and Diaporthe fungi have been reported as the main causal agents of canker, branch dieback, and shoot blight of this crop (Michailides and Hasey 2010;Moral et al. 2019). The occurrence of these fungi associated with this disease has already been described in the main walnut-growing regions of the world, such as California (Chen et al. 2014;Michailides and Hasey 2010;Trouillas et al. 2010), China (Li et al. 2015), Chile (D ıaz et al. 2018), Spain (L opez- Moral et al. 2020), Czech Republic (Eichmeier et al. 2020), and Italy (Gusella et al. 2020). ...
... These fungi produce persistently viable spores in the pycnidia, serving as a primary inoculum source to infect plant tissues, which are spread by wind and rain splash and eventually by insects in late winter, spring, and summer. Natural or artificial wounds such as abscission points or pruning/harvest wounds, respectively, may always be necessary for pathogen infection in this pathosystem (Michailides and Hasey 2010;Moral et al. 2019). In regions with rainy, moderately hot springs combined with subsequent long, dry, hot periods during late spring and summer (Mediterranean climate) may favor the dispersal of these pathogens and their infection of walnut tissues (L opez- Moral et al. 2020). ...
... These reports demonstrated that Botryosphaeriaceae fungi always showed higher optimum temperature for infection than Diaporthe fungi. This statement confirms that the warm temperatures occurring from late spring to the beginning of autumn in both Spanish and Californian walnut-growing regions favor infection of walnut tissues by Botryosphaeriaceae fungi (Agust ı-Brisach et al. 2019; Michailides and Hasey 2010;Moral et al. 2019). In addition, these differences in the optimum temperature for infection between species could favor the earlier colonization of walnut tissues by Botryosphaeriaceae fungi, making optimum development of Diaporthe species difficult because of niche competitiveness. ...
Shoot blight and branch dieback of English walnut has been associated with a broad diversity of Botryosphaeriaceae and Diaporthe fungi worldwide. These pathogens affect both wood and fruit tissues, infecting the tree through mechanical or natural wounds. Fruit infections can play an important role in the life cycle of the disease. Thus, the effects of cultivar, and fruit maturity on English walnut fruit infection by Botryosphaeriaceae (Botryosphaeria dothidea, Neofusicoccum mediterraneum and N. parvum) and Diaporthe (Diaporthe neotheicola and Dia. rhusicola) fungi were evaluated. The infection and disease progress from inoculated attached fruits or by inoculating fruit abscission wounds was evaluated both under laboratory and field conditions. An initial experiment evaluating two inoculation methods was conducted, but there were not significant differences in disease severity between inoculations with mycelial plugs or conidial suspensions. A total of eight cultivars were selected to evaluate their susceptibility to fruit infection, with ‘Chandler’ being the most susceptible for all the pathogens tested compared to the other cultivars. Botryosphaeriaceae showed higher aggressiveness on fruit collected at beginning- or middle summer, while Diaporthe showed similar aggressiveness regardless of fruit maturity stage. Botryosphaeriaceae fungi were able to colonize the entire surface of the inoculated fruit, reaching the peduncle and infecting the attached shoot; while Diaporthaceae fungi were not able to colonize the surface of the inoculated fruit quickly enough to infect the attached shoot before the peduncle was naturally separated from the shoot. Finally, we demonstrated that both Botryosphaeriaceae and Diaporthe fungi can infect shoots by inoculating the natural fruit abscission wounds in the field. This study generates new insights into the influence of fruit infection leading to shoot blight and branch dieback of English walnut caused by Botryosphaeriaceae and Diaporthe fungi.
... In addition to water stress, monoculture, and the intensification of agricultural operations, new cultivars have contributed to immense disease problems in pistachio. The panicle and shoot blight of pistachio, and blight of walnut, causes significant economic loss to pistachio in most of the nut-growing areas (Moral et al., 2019). Walnut blight, also called bacterial blight of walnut, is caused by Xanthomonas campestris (Pammel) Dowson pv. ...
... However, Botryosphaeria dothidea is the primary causal organism of panicle and shoot blight of pistachio. The success of causing infection in a given host depends upon the virulence of the species, but other factors like its saprophytic attitude or ability to infect and colonize neighbouring hosts from which it can leap also play a role (Moral et al., 2019). The disease was first identified in 1984 in California (Michailides et al., 1998). ...
... It has been reported that Botryosphaeria panicle and shoot blight causes major destruction to current growth, including shoots, panicles, and leaves (Ntahimpera et al., 2002). It was also reported that shoot infection occurs at postharvest through the leaf, bud, and panicle scars (Moral et al., 2019). , 1993). ...
Walnut is one the oldest fruits cultivated worldwide and is affected by various diseases. Due to the large size of the tree, disease management in walnut is difficult and tiresome. Although the walnut tree can resist/tolerate many diseases and give good produce. Still, some diseases, mainly anthracnose, blight. and Phytophthora root rot, cause severe infection, threaten the tree's life, and significantly afect nut production. The traditional control strategies are effective to some extent, but given economic value, modern integrated management measures are required to improve yield and quality produce. The pistachio, also known as green almond, is the world's fifth most important commercial nut crop. Several diseases have been reported affecting pistachio production. The major diseases are botryosphaeria panicle and shoot blight, Verticillium wilt, phytophthora root and crown rot, and Alternaria late blight. These diseases are considered the main constraints in the production of pistachios and cause heavy losses. The present chapter describes the major diseases in walnut and pistachio and their management options. Keywords: diseases, integrated disease management, pistachio, walnut
... The diversity and pathogenicity of Botryosphaeriaceae species associated with branch dieback of olive trees detected in this study suggest that no one single agent is involved in the etiology but that it is the result of multiple infections of different Botryosphaeriaceae species, which are variable in assemblages among regions and sites. The co-occurrence of different Botryosphaeriaceae associated with cankers with a V-shaped necrotic sector and dieback symptoms is a recurring aspect in the pathosystems in which these pathogens are involved in both forestry and agriculture [41][42][43][44][45]. The complex etiology detected in this study is in accordance with the results obtained by Urbez-Torres et al. [14] in California. ...
Extensive collar rot, sunken and bleeding cankers, shoot blight, and fruit rot symptoms on olive trees have recently been observed in several orchards in Italy. Since there is little information about the etiology of these diseases and given the high economic relevance of this iconic crop, a study was conducted from autumn 2017 to summer 2022, in four Italian regions, to define the occurrence, distribution and impact of the main pathogens involved. A total of 1064 symptomatic olive samples were collected and processed. Based on colony appearance, micromorphological analysis and DNA sequence data, thirty-eight species, including eighteen Botryosphaeriaceae species belonging to five genera and fifteen Phytophthora species, were isolated and identified, thirteen of which, Diplodia africana, D. fraxini, D. subglobosa, Dothiorella omnivora, Do. sarmentorum, Do. sempervirentis, Sardiniella urbana (Botryosphaeriaceae), Phytophthora cactorum, P. cinnamomi, P. citricola, P. crassamura, P. niederhauserii and P. pseudocryptogea, are reported here for the first time in olive trees. Pathogenicity tests performed on unripe drupes and on potted olive seedlings completed Koch postulates and highlighted that several species of Botryosphaeriaceae and Phytophthora represent a growing threat to olive trees.
