Influence of Sweet Potato Cultivars in Combination with a Biological Control Agent (Nematoda: Heterorhabditis heliothidis ) on Larval Development of the Banded Cucumber Beetle (Coleoptera: Chrysomelidae)

Abstract

Interactions between larvae of the banded cucumber beetle ( Diabrotica balteata LeConte), a resistant cultivar (‘Regal’), a susceptible sweet potato clone (SC-1149-19), and a nematode arthropod parasite, Heterorhabditis heliothidis (Khan, Brooks, and Hirschman 1976) Poinar, Thomas, and Hess 1977, South Carolina strain, were evaluated. Plant resistance in the cultivar Regal was active against younger larvae. Reduced adult weights and fewer emerging adults were observed when second instars were exposed to the parasite on sweet potato tissue, and the eclosion period was longer for second instars and reduced for third instars. Exposure to the resistant cultivar reduced the eclosion period of second instars as compared with larvae exposed to the susceptible clone, whereas no differences were observed among plant entries for third instars. When second instars were exposed to the parasite, the eclosion period was reduced and no differences were noted for third instars. The duration of the eclosion period was negatively correlated with adult weight.