Planting cover crops is an increasingly prevalent sustainable management technique that can increase soil health by increasing microbial abundance and diversity. These soil microbes can improve plant health and alter plant defenses against insects but less is known how the soil microbiome affects insect pest fitness and microbiome composition. The western corn rootworm (WCR) is a major belowground pest of corn throughout the US Corn Belt. Management relies heavily on the planting of transgenic crops expressing Bacillus thuringiensis (Bt). In this study, we ask how does the soil microbiome impact western corn rootworm fitness, microbiome composition, and transgenic crop effectiveness. To do this, we applied soil microbes from continuously managed cover crop fields and those from traditionally managed fields to Bt and non-Bt corn seedlings. We then reared Bt-resistant and -susceptible WCR for 5 days on treated seedlings. Using 16S sequencing, we characterized bacterial communities of the soil, Bt and non-Bt corn rhizospheres, and Bt-resistant WCR larvae.
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