The Colorado potato beetle, Leptinotarsa decemlineata (Say), overwinters in the soil as a diapausing adult. Large numbers of adult beetles fly and walk from potato, Solanum tuberosum L. (Solanaceae), fields to the surrounding forested edges late in the summer (Voss and Ferro 1990). This movement can result in higher densities of diapausing adults in the soil along these edges than in potato fields (Weber and Ferro 1993). Beetles that overwinter in these woody borders show lower levels of overwintering mortality (Weber et al. 1994). Survivorship of overwintering Colorado potato beetle adults was positively correlated with soil depth for studies conducted adjacent to potato fields in New Jersey (Lashomb et al. 1984) and Massachusetts (Weber and Ferro 1993). Lashomb et al. (1984) reported that a 10-cm increase in soil depth decreased winter mortality by 32%.
Description of Spring Emergence by the Colorado Potato Beetle, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae), in New Jersey