昆虫病原线虫(EPNs)是普遍存在的土壤繁荣的生物,它们使用化学线索来寻找和感染居住在土壤中的节肢动物,产生不同水平的生物防治。超越土壤应用,科学家和从业者开始探索将EPNs应用于农作物叶子上的选择,以尝试管理叶子害虫。尽管取得了一些成功,特别是保护性配方,目前还不确定EPN是否真的能在叶层环境中生存,并成功控制了叶面害虫。在这种情况下,我们测试了商业生产的Steinernemafeltiae和S.carpocapsae的潜力,生物防治领域最常用的两种EPN,在控制具有经济重要性的鳞翅目叶面害虫方面,即Tutaabsoruta和Spodopteraspp。毛毛虫作为模型。我们首先测试了两种EPN对鳞翅目毛虫的存活率和功效,甜椒和莴苣叶,在受控条件和商业温室条件下,分别。随后,我们探索了EPN对叶球中通常遇到的环境线索的行为反应,并分析了植物挥发性有机化合物(VOCs)。我们的结果表明,毛毛虫和S.carpocapsae成功存活并感染了叶毛虫,在商业实践中达到与标准化学农药相似的控制水平。值得注意的是,两种EPN物种都存活下来,并在叶球中保持有效达四天,只需要几个小时就能成功穿透毛毛虫。有趣的是,美国长毛被番茄植物的挥发性有机化合物所吸引,倾向于更喜欢那些来自毛虫诱导的植物,这表明线虫可能会主动向寄主觅食,尽管在其进化过程中从未暴露于叶载挥发物。本研究表明,硬脂线虫在控制温室中的主要叶面害虫以及成为叶面生物防治的关键参与者方面具有很高的潜力。特别是,EPNs使用叶面挥发性有机化合物来定位毛毛虫宿主的发现在应用技术和负担得起的有效剂量方面开辟了新的机会。
Entomopathogenic nematodes (EPNs) are ubiquitous soil-thriving organisms that use chemical cues to seek and infect soil-dwelling arthropods, yielding various levels of biological control. Going beyond soil application, scientists and practitioners started exploring the option of applying EPNs onto the foliage of crops in attempts to manage leaf-dwelling insect pests as well. Despite some success, particularly with protective formulations, it remains uncertain whether EPNs could indeed survive the phyllospheric environment, and successfully control foliar insect pests. In this context, we tested the potential of commercially produced Steinernema feltiae and S. carpocapsae, two of the most commonly used EPNs in the field of biological control, in controlling Lepidopteran foliar pests of economic importance, i.e. Tuta absoluta and Spodoptera spp. caterpillars as models. We first tested the survival and efficacy of both EPN species against the Lepidopteran caterpillars when applied onto tomato, sweet pepper and lettuce leaves, under controlled conditions and in commercial greenhouse conditions, respectively. Subsequently, we explored the behavioural responses of the EPNs to environmental cues typically encountered in the phyllosphere, and analysed plant volatile organic compounds (VOCs). Our results show that both S. feltiae and S. carpocapsae successfully survived and infected the foliar caterpillars, reaching similar level of control to a standard chemical pesticide in commercial practices. Remarkably, both EPN species survived and remained effective up to four days in the phyllosphere, and needed only a few hours to successfully penetrate the caterpillars. Interestingly, S. feltiae was attracted to VOCs from tomato plants, and tended to prefer those from caterpillar-induced plants, suggesting that the nematodes may actively forage toward its host, although it has never been exposed to leaf-borne volatiles during its evolution. The present study shows the high potential of steinernematids in managing major foliar pests in greenhouses and in becoming a key player in foliar biological control. In particular, the discovery that EPNs use foliar VOCs to locate caterpillar hosts opens up new opportunities in terms of application techniques and affordable effective doses.