Going underground with predatory mites for the conservation biological control of soil pest

Species of soil predatory mites feed on a diverse diet making them excellent candidates for conservation biological control programs. Free living nematodes (FLNs) are commonly found in soils and serve as prey for many soil predatory mites (SPMs). Some species must feed on FLN to lay eggs and others will need them to complete immature development. Surprisingly, as far as we know, FLNs have never been used as alternative prey to enhance the efficacy of SPM for conservation biological control. Here we present results of two case studies where we provisioned the FLN Rhabditella axei as complementary prey for predatory mites. In the first study, we used the SPM Macrocheles embersoni for housefly control and in the second, the SPM Stratiolaelaps scimitus for the control of the root knot nematode Meloidogyne incognita. In both systems, complementing the diet of predatory mites with FLNs resulted in higher predator abundance and better biological control, compared to the negative control and the release of predators without FLNs. Future research will focus on manipulations of soil management and evaluating soil amendments to enhance the abundance and diversity of FLNs and predatory mites in cropping systems for enhanced conservation biological control of soil pests.