Tuesday, 19 November 2002
D0431

This presentation is part of : Display Presentations, Section F. Crop Protection Entomology

Effects of leaf epicuticular waxes on the foraging efficiency of Diaretiella rapae (Braconidae: Aphidiinae) searching for Brevicoryne brassicae (Aphididae) on cauliflower

Grant L. Gentry, Department of Entomology, University of Maryland, Department of Entomology, 4112 Plant Sciences Bldg, College Park, MD

Morphological or physiological characters of plants may affect the foraging abilities of visiting natural enemies. Heavy epicuticular wax blooms on different varieties of Brassica have been shown to impede predators searching for aphids and other herbivores. Here, I report on the effects of epicuticular wax on the foraging abilities of parasitoids. The behavior of the wasp Diaratiella rapae was studied as it foraged for the aphid Brevicornye brassicae on varieties of cauliflower with heavy and light wax blooms. Wasps on heavier wax bloom plants foraged more slowly, spent more time grooming, and were often unable to find incipient colonies of aphids before giving up. When the wax was removed the wasp's foraging efficiency and efficacy improved significantly, approaching that of the low wax variety. Leaf epicuticular wax was shown to greatly impede the ability of a parasitoid to forage for and locate its host.



Species 1: Hymenoptera Braconidae Diaretiella rapae
Species 2: Homoptera Aphididae Brevicoryne brassicae (cabbage aphid)
Keywords: parasitoid, epicuticular wax

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