Beneficial soil microbes have long been recognized for their ability to improve plant growth, to antagonize pathogens and to prime plants against biotic stressors. Nevertheless, their ability to enhance plant resistance against arthropod pests remains largely unexplored, especially in crop plants such as pepper. Herein, we assessed the effects of several fungal and bacterial species/strains applied in the soil on the performance of key pests of pepper plants. Specifically, we recorded the impact of pepper inoculation with commercial strains of beneficial bacteria (Bacillus amyloliquefaciens and Pseudomonas spp.) as well as fungi (Trichoderma spp. and Cordyceps fumosorosea) on the population growth of the green peach aphid, Myzus persicae, and the two-spotted spider mite, Tetranychus urticae. Furthermore, we recorded the effects of microbial inoculation on plant growth parameters, such as stem and root weight. We found that both pests can be negatively affected by microbial inoculation: spider mites laid up to 40% fewer eggs, and the number of aphids were up to 50% less on pepper-inoculated plants, depending on the microbe. We also recorded a variation among the tested microbes in their impact on herbivore performance, but no significant effects were found on plant biomass. Our results add to the growing literature that beneficial soil microbes may be capable of exerting biocontrol capabilities against aboveground herbivorous pests possibly, among other means, via the elicitation of plant defense responses.

中文翻译：

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有益土壤微生物对辣椒中的蜘蛛螨和蚜虫产生负面影响

长期以来，人们已经认识到有益的土壤微生物具有改善植物生长、对抗病原体和使植物抵御生物胁迫的能力。然而，它们增强植物对节肢动物害虫的抗性的能力在很大程度上仍未得到探索，尤其是在辣椒等作物植物中。在此，我们评估了土壤中应用的几种真菌和细菌物种/菌株对辣椒植物主要害虫的性能的影响。具体来说，我们记录了辣椒用商业菌株（解淀粉芽孢杆菌和假单胞菌属）以及真菌（木霉属和烟叶虫草属）对桃蚜种群增长的影响，Myzus persicae和二斑叶螨Tetranychus urticae。此外，我们记录了微生物接种对植物生长参数（例如茎和根重量）的影响。我们发现这两种害虫都会受到微生物接种的负面影响：根据微生物的不同，红蜘蛛产卵量减少了 40%，而辣椒接种植物的蚜虫数量减少了 50%。我们还记录了测试微生物对食草动物性能影响的差异，但未发现对植物生物量的显着影响。我们的研究结果增加了越来越多的文献，即有益的土壤微生物可能能够通过引发植物防御反应等方式对地上食草害虫发挥生物防治能力。