Exploration of factors influencing crop protection against wireworm herbivory (Coleoptera: Elateridae) using Beauveria bassiana

Pest wireworms (Coleoptera: Elateridae) negatively affect crops worldwide. Traditionally controlled by chemical insecticides, wireworms now have limited control options due to new regulations stemming from environmental and health concerns. The use of biological control agents, such as entomopathogenic fungi, is an alternative strategy. I investigated possible mechanisms of potato protection against wireworms by B. bassiana. I found that fungal inoculation did not cause mortality in three wireworm species. Wireworms avoided B. bassiana as granules and spores, and tissue from inoculated plants. Fungal inoculation of Agriotes lineatus caused up to 33% decreased feeding time in the lab; however, tubers from inoculated plants were not protected from herbivory. Beauveria bassiana was detected inside plants, but plant performance was not affected. The wireworm internal bacterial load increased after B. bassiana inoculation, and there were shifts in community members, without affecting mortality. This study provides insight into the non-lethal effects of B. bassiana.