Seed treatment of maize with Bacillus pumilus strain INR-7 affects host location and feeding by Western corn rootworm, Diabrotica virgifera virgifera

Abstract

Western corn rootworm (WCR), Diabrotica virgifera virgifera is an important pest of maize and the costs of control and yield loss are estimated at $1 billion per year in the USA. As a specialist herbivore, WCR has evolved to use host odors and secondary plant metabolites as cues for host location and phagostimulants. This study reports that rhizobacteria applied as seed treatments to maize affect host-seeking behavior of WCR larvae. The results of a dual-choice test showed that a significantly higher percentage (76%) of WCR larvae chose untreated control plants than plants treated with the single Bacillus pumilus strain INR-7 (24%). In no-choice feeding tests, WCR larvae-fed INR-7-treated plants weighed significantly less than larvae-fed untreated plants or plants treated with bacilli blends. Overall, the results demonstrate that B. pumilus INR-7 can enhance resistance of maize against damage by WCR larvae. The implication of these findings is discussed in the context of using beneficial rhizobacteria in integrated pest management of corn rootworm.