Harnessing the soil food web for the biological control of root-knot nematodes

许多掠食性螨是多面手，以不同的饮食为食，使它们成为保护生物控制计划的优秀候选者。然而，虽然经常报告它们对地上害虫的影响，但只有很少的研究集中在螨的地下相互作用上。拟议的项目旨在利用农业生态系统中的土壤食物网，即微生物、自由生活的线虫（FLN）和捕食性螨之间的营养联系，对根结线虫（RKN）进行生物防治。我们假设FLN代表螨类的高质量饮食（例如，由于营养价值高的ω 3脂肪酸），增强捕食者适应性，进而捕食RKN。在实验室、温室和田间实验中，这些营养相互作用在四个工作包中进行了研究。选择Lettera作为模式植物，因为在以色列和巴勒斯坦当局种植的所有栽培品种都易受RKN影响，因此遭受产量损失。本试验以黑水虻幼虫堆肥作为FLN的饲养基质和有机肥。BSFL是动植物农业废物管理的可持续解决方案，具有作为有机农业土壤改良剂的潜力。解决的主要研究问题是：1）FLN和螨类物种自然共同出现在耕地与已知的RKN的历史，从而有一个很好的潜力，相互作用的生物防治剂？2)哪些FLN物种最能增强捕食者的适应性（例如繁殖，生物量），这些FLN是否代表了RKN存在下螨类的替代饮食？3)与BSFL堆肥及其线虫食草动物相关的微生物对捕食性螨丰度、植物适合度和螨对RKN生物防治的单独和协同作用是什么？4)BSFL修正案作为耕作实践对螨类生物防治功能以及对土壤健康、植物对叶面食草动物的抗性和植物产量的影响是什么？总的来说，预期的三边合作将确定、评估和保护土著FLN和土壤捕食螨，以生物控制RKN。这将促进以色列和巴勒斯坦权力机构的种植者采用可持续农业战略。

Many predatory mites are generalists and feed on a diverse diet, making them excellent candidates for conservation biological control programs. However, while their impact on above ground pests is frequently reported, only few studies have focused on below ground interactions of mites. The proposed project aims to harness the soil food web in agroecosystems, namely the trophic link between microorganisms, free-living nematodes (FLN) and predatory mites, for the biological control of root-knot nematodes (RKN). We hypothesise that FLN represent a high quality diet (e.g. due to nutritional valuable omega 3 fatty acids) for mites, enhancing predator fitness and in turn predation on RKN. These trophic interactions are investigated in four working packages in laboratory, greenhouse and field experiments. Lettuce is chosen as a model plant, as all cultivars grown in Israel and the Palestinian Authorities are susceptible to RKN, and accordingly suffer from yield loss. Compost of the black soldier fly larvae (BSFL, Hermetia illucens) is used as a rearing substrate for FLN and as organic fertilizer in the experiments. BSFL is a sustainable solution for animal and plant agriculture waste management, with potential as soil amendment in organic farming. The major research questions addressed are: 1) Which FLN and mites species do naturally co-occur in arable fields with known RKN history, thus having a good potential to interact as biocontrol agents? 2) Which FLN species best enhance predator fitness (e.g. reproduction, biomass) and do these FLN represent an alternative diet for mites in the presence of RKN? 3) What are the separate and synergistic effects of microorganisms associated with BSFL compost and their nematode grazers on predatory mite abundance, plant fitness, and on RKN biocontrol by mites? 4) What is the impact of BSFL amendment as arable practice on biocontrol function of mites as well as on soil health, plant resistance to foliar herbivory and plant yield? Overall, the intended trilateral collaboration will identify, evaluate and conserve indigenous FLN and soil predatory mites for the biological control of RKN. This will foster sustainable farming strategies to be adopted by the growers in Israel and the Palestinian Authority.