Plant-fungi-insect interactions: The effect of cover crops and Metarhizium brunneum on wireworm

Wireworms, the larval stage of click beetles (Coleoptera: Elateridae), have resulted in severe damage to potato crops across Canada. Many of the insecticides used to manage wireworm populations are now banned due to their negative effect on both the environment and human health. Recent reports indicate that certain cover crops can reduce wireworm populations through natural compounds released by the growing plant (allelopathy) or after they are mulched into the soil (fumigants). The use of the entomopathogenic fungus, Metarhizium brunneum, is also seen as an effective alternative strategy to reduce wireworm populations. This study investigated potential interactions between M. brunneum and the cover crops brown mustard, buckwheat, sorghum-Sudan grass and barley in the context of using the combination of the cover crops and fungus as a strategy to reduce Limonius agonus populations in southwestern Ontario.