Location and abundance of adult Colorado potato beetles (Coleoptera: Chrysomelidae) following potato harvest

Abstract

Colorado potato beetle, Leptinotarsa decemlineata (Say), population biology was investigated after Irish potatoes, Solanum tuberosum (L.), were harvested in eastern North Carolina. The abundance of adult Colorado potato beetles following potato harvest was estimated by taking more than 450 visual transects in 45 commercial potato fields in July and August, 1993 and 1994. Few second- and third-generation Colorado potato beetle egg masses and larvae, volunteer potato plants and wild hosts such as horsenettle, S. carolinense L., were encountered, suggesting that Colorado potato beetle generations produced after potatoes are harvested in June and early July do not contribute significantly to the overall overwintering population. Location and abundance of overwintering adult Colorado potato beetles within the soil in fields previously planted in potato were determined. Densities of overwintering adults in soil along field edges were greater than those within fields prior to emergence in the spring, suggesting that adults moved toward field edges to overwinter. However, given that the area within potato fields was much greater than the area along field edges, the estimated total number of overwintering adults within fields was greater than along the edges. In light of these results, tillage at different times between crop production seasons was evaluated for its effect on overwintering Colorado potato beetle survival, but was found to have little effect.