Cover crop effects on natural enemies of the Colorado potato beetle

This study examined the potential for the management of Colorado potato beetles (Coleoptera: Chrysomelidae) through the use of cover crop mulches in potato fields. Three types of ground covers were compared in an experimental potato field in 2006 and 2007 for their effect on Colorado potato beetle natural enemy species diversity, abundance and effectiveness as biocontrol agents of the focal pest. Species abundance in the predator assemblage was more evenly distributed in plots that had no cover crop than where cover crops were present, indicating that cover crop treatments altered the relative abundance of natural enemy species. The most abundant predators in cover crop treatments were coccinellids. Molecular gut analysis of field collected natural enemies revealed that Colorado potato beetle consumption is not affected by the presence of cover crops: predator species consumed similar amounts of prey irrespective of cover treatment. The most abundant natural enemy species was Coleomegilla maculata (Coleoptera: Coccinellidae) across all treatments, but only 2.9% of the tested individuals were positive for Colorado potato beetle DNA. The highest proportion of predator species positive for Colorado potato beetle DNA were Perillus bioculatus and Podisus maculiventris (Heteroptera: Pentatomidae). Our results indicate that habitat manipulation is a potentially viable method of Colorado potato beetle population regulation with natural enemies.