Entomopathogenic Fungi

昆虫病原真菌
  • 文章类型: Journal Article
    在巴西,种植者专门为自己使用生产有益微生物是一种被称为“农场生产”的做法。关于农场生物杀虫剂,它们最初在1970年代被部署用于多年生和半多年生作物的害虫,但是,自2013年以来,它们的使用已经扩展到玉米等一年生作物的害虫,棉花,和大豆。目前正在用这些农场制剂处理数百万公顷的土地。本地生产降低了成本,满足当地需求,减少对环境有害的化学农药的投入,促进建立更可持续的农业生态系统。批评者认为,如果不实施严格的质量控制措施,农场制剂存在以下风险:(1)被可能包括人类病原体的微生物污染或(2)含有很少的活性成分,影响田间功效。细菌杀虫剂的农场发酵占主导地位,特别是针对鳞翅目害虫的苏云金芽孢杆菌。然而,在过去的5年里,昆虫病原真菌的产量快速增长,主要用于控制吸汁昆虫,例如粉虱(烟粉虱(Gennadius))和玉米叶斗(Dalbulusmaidis(DeLong和Wolcott))。相比之下,昆虫病毒的农场生产增长有限。大多数CA。巴西有500万农村生产者拥有中小型房地产,尽管绝大多数仍然没有进行生物农药的农场生产,这个话题引起了他们的兴趣。许多采用这种做法的种植者通常使用非无菌容器作为发酵罐,导致制剂质量差,并且已经报告了失败的案例。另一方面,一些非正式报告表明,即使受到污染,农场准备工作也可能有效,什么可以解释,至少部分地,由液体培养基中微生物池分泌的杀虫次生代谢产物。的确,关于这些微生物生物农药的功效和作用方式的信息不足。通常是大型农场,一些拥有超过20,000公顷的连续耕地,产生污染程度低的生物农药,因为他们中的许多人拥有先进的生产设施,并有机会获得专业知识和训练有素的员工。农场生物农药的吸收预计将继续,但采用率将取决于诸如选择安全,和实施良好的质量控制措施(符合巴西新兴法规和国际标准)。介绍和讨论了农场生物杀虫剂的挑战和机遇。
    In Brazil, the production of beneficial microorganisms by growers exclusively for their own use is a practice known as \"on-farm production\". Regarding on-farm bioinsecticides, they were initially deployed for pests of perennial and semi-perennial crops in the 1970s but, since 2013, their use has extended to pests of annual crops such as maize, cotton, and soybean. Millions of hectares are currently being treated with these on-farm preparations. Local production reduces costs, meets local needs, and reduces inputs of environmentally damaging chemical pesticides, facilitating establishment of more sustainable agroecosystems. Critics argue that without implementation of stringent quality control measures there is the risk that the on-farm preparations: (1) are contaminated with microbes which may include human pathogens or (2) contain very little active ingredient, impacting on field efficacy. The on-farm fermentation of bacterial insecticides predominates, especially that of Bacillus thuringiensis targeting lepidopteran pests. However, there has been a rapid growth in the past 5 years in the production of entomopathogenic fungi, mostly for the control of sap-sucking insects such as whitefly (Bemisia tabaci (Gennadius)) and the corn leafhopper (Dalbulus maidis (DeLong and Wolcott)). In contrast, on-farm production of insect viruses has seen limited growth. Most of the ca. 5 million rural producers in Brazil own small or medium size properties and, although the vast majority still do not practice on-farm production of biopesticides, the topic has aroused interest among them. Many growers who adopt this practice usually use non-sterile containers as fermenters, resulting in poor-quality preparations, and cases of failure have been reported. On the other hand, some informal reports suggest on-farm preparations may be efficacious even when contaminated, what could be explained, at least partially, by the insecticidal secondary metabolites secreted by the pool of microorganisms in the liquid culture media. Indeed, there is insufficient information on efficacy and mode of action of these microbial biopesticides. It is usually the large farms, some with > 20,000 ha of continuous cultivated lands, that produce biopesticides with low levels of contamination, as many of them possess advanced production facilities and have access to specialized knowledge and trained staff. Uptake of on-farm biopesticides is expected to continue but the rate of adoption will depend on factors such as the selection of safe, virulent microbial strains and implementation of sound quality control measures (compliance with emerging Brazilian regulations and international standards). The challenges and opportunities of on-farm bioinsecticides are presented and discussed.
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  • 文章类型: Journal Article
    昆虫病原真菌是昆虫的重要天敌。然而,关于这些真菌的昆虫抑制潜力以及耕作管理对此可能产生的影响的信息很少。同时,由于农业集约化,自然景观的变化导致了相当大的生物多样性丧失和随之而来的生态系统服务衰减。然而,在农业生态系统中采用农林业等做法可以促进保护生物多样性的非生物和生物条件,从而恢复生态系统服务的提供。这里,我们评估了管理系统(农林业或全日)对巴西咖啡种植园昆虫病原真菌的害虫抑制潜力的影响。我们使用昆虫诱饵方法和生存分析来评估昆虫病原真菌的杀死速度及其在两个耕作系统的土壤样品中的存在。我们发现,暴露于农林业土壤的昆虫比暴露于阳光充足的土壤的昆虫死亡更快。从诱饵昆虫中分离出的真菌,绿僵菌是最常见的,紧随其后的是Beauveria。同时,镰刀菌经常被分离为原发性或继发性感染。我们认为,昆虫的差异生存表明农林业中昆虫病原真菌具有更大的抑制潜力,这可以通过多元化的景观来促进,微气候稳定性,减少了农林系统中的土壤干扰。此外,我们的结果提供了一个有用的证明,潜在的使用昆虫诱饵方法来调查害虫抑制潜力通过诱饵昆虫死亡率,我们称之为“诱饵生存技术”。\"
    Entomopathogenic fungi are important natural enemies of insects. However, there is little information on the insect-suppressive potential of these fungi and possible effects of farming management on this. Meanwhile, changes in natural landscapes due to agricultural intensification have caused considerable biodiversity loss and consequent decay of ecosystem services. However, the adoption of practices such as agroforestry in agroecosystems can foster abiotic and biotic conditions that conserve biodiversity, consequently restoring the provision of ecosystems services. Here, we assessed the effect of management systems (agroforestry or full-sun) on the pest-suppressive potential of entomopathogenic fungi in Brazilian coffee plantations. We used the insect bait method coupled with survival analyses to assess the speed of kill by entomopathogenic fungi and their presence in soil samples from both farming systems. We found that insects exposed to agroforestry soils died more quickly than insects exposed to full-sun soils. Of the fungi isolated from the bait insects, Metarhizium was found most frequently, followed by Beauveria. Meanwhile, Fusarium was frequently isolated as primary or secondary infections. We propose that the differential survival of insects is indicative of a greater suppressive potential by entomopathogenic fungi in agroforestry, and that this could be promoted by the diversified landscape, microclimatic stability, and reduced soil disturbance in agroforestry systems. Furthermore, our results provide a useful demonstration of the potential use of the insect bait method to investigate pest-suppressive potential through bait insect mortality, and we term this the \"bait survival technique.\"
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  • 文章类型: Journal Article
    Fusarium oxysporum exhibits insect pathogenicity-however, generalized concerns of releasing phytopathogens within agroecosystems marred its entomopathogenicity-related investigations. In a previous study, soils were sampled from Douro vineyards and adjacent hedgerows. In this study, 80 of those soils were analyzed for their chemical properties and were subsequently co-related with the abundance of entomopathogenic F. oxysporum, after insect baiting of soils with Galleria mellonella and Tenebrio molitor larvae. The soil chemical properties studied were organic matter content; total organic carbon; total nitrogen; available potassium; available phosphorus; exchangeable cations, such as K⁺, Na⁺, Ca2+, and Mg2+; pH; total acidity; degree of base saturation; and effective cation exchange capacity. Entomopathogenic F. oxysporum was found in 48 soils, i.e., 60% ± 5.47%, of the total soil samples. Out of the 1280 insect larvae used, 93, i.e., 7.26% ± 0.72%, were found dead by entomopathogenic F. oxysporum. Stepwise deletion of non-significant variables using a generalized linear model was followed by a generalized linear mixed model (GLMM). A higher C:N (logarithmized) (p < 0.001) and lower exchangeable K⁺ (logarithmized) (p = 0.008) were found significant for higher fungal abundance. Overall, this study suggests that entomopathogenic F. oxysporum is robust with regard to agricultural changes, and GLMM is a useful statistical tool for count data in ecology.
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