Seasonal Changes in Habitat Preference by Coleomegilla maculata: Implications for Colorado Potato Beetle Management in Potato

Seasonal abundance, dispersal, and overwintering of the 12-spotted ladybird beetle, Coleomegilla maculata (DeGeer), in the mid-Atlantic states were investigated to assess the potential to manipulate the habitat of this predator to increase its impact on Colorado potato beetle, Leptinotarsa decemlineata (Say), management in commercial potato plantings. C. maculata populations were highest in corn fields through August, and overwintering aggregations were found most commonly in habitats adjacent to these fields. Although adult and larval populations of C. maculata were synchronized with first-generation potato beetle eggs and small larvae, they were concentrated in wheat rather than potato fields because most of the potato plants had not yet emerged when C. maculata adults dispersed from their overwintering sites. The subsequent generation of C. maculata tended to aggregate in corn rather than potato in late May and early June. Therefore, given the current mixture of crops as well as climatic and marketing limitations on planting date for potatoes, the potential for habitat manipulation to increase the impact of C. maculata on Colorado potato beetle management in potato in the mid-Atlantic states appears to be limited.