Cucurbit Genetics Cooperative Report 1:30 (article 28) 1978
Insect Associations with Cucurbita in Illinois
A. M. Rhodes, W. L. Howe, R. L. Metcalf and P. Y. Lu
University of Illinois, Urbana, IL 61801
For the past seven years we have evaluated the host preference of several insect species that were attracted to five cultivated and 14 mesophytic and xerophytic wild Cucurbita spp. The striped cucumber beetles, Acalymma vittata, were most attracted to the young growth of the Maxima and Ficifolia groups and the wild xerophytic Digitata group. The spotted cucumber beetle, Diabrotica undecimpunctata howardi, exhibited a high affinity for the Maxima, the wild Lundelliana and Digitata groups. The western corn rootworm, Diabrotica vigifera, preferred the Digitata and the Lundelliana groups. The squash vine borer, Melittia Cucurbitae, severely injured the Maxima and Pepo groups. The squash bug, Anasa tristis, show a high ovipositional preference for the Maxima and Mixta groups. All Cucurbita spp. were poor hosts for the melon aphid, Aphis gossypii, with the wild Sororia and Ficifolia groups most suitable for reproduction. The potato leafhopper, Empoasca fabae, preferred cultivated species but oviposited on all wild species except C. foetidissima. The potato aphid, Macrosiphum euphorbiae, preferred the Sororia and Pepo groups. Overall C. moschata showed the most resistance to the various insect species.
Systematic counting of cucumber and corn rootworm beetles in Cucurbita blossoms was conducted from June to October, 1977. The striped cucumber beetle was the dominant species in June, followed by western corn rootworm, and finally by southern corn rootworms. The population of northern corn rootworms, Diabrotica longicornis, was low throughout the season.