Phytophagous Insect Associations with Cucurbita in Illinois

Abstract

Phytophagous insect associations with 5 cultivated and 14 mesophytic and xerophytic wild Cucurbita spp. were recorded for 4 consecutive years. Overwintering striped cucumber beetles, Acalymma vittata (Fab.) were most attracted to the young growth of the Maxima and Ficifolia groups and the wild xerophytic Digitata group. Foliage feeding responses were strongest on the latter group. The spotted cucumber beetle, Diabrotica undecimpunctata howardi Barber, exhibited a high affinity for the Maxima, the wild Lundelliana and Digitata groups. The squash vine borer severly injured the Maxima and Pepo groups. The squash bug, Anasa tristis (DeGeer), showed a high ovipositional preference for the Maxima and Mixta groups and a low preference for all other groups. All Cucurbita spp. were poor hosts for the melon aphid, Aphis gossypii (Glover), with the wild Sororia and Ficifolia groups most suitable for reproduction. The potato leafhopper, Empoasca fabae (Harris), preferred cultivated species but oviposited on all wild species except C. foetidissima (HBK). The potato aphid, Macrosiphum euphorbiae (Thomas), preferred the Sororia and Pepo groups. Principle component analysis revealed that the striped cucumber beetle, squash vine borer and the squash bug showed similar host preference patterns with the Maxima group being the most favored.