Parasitism of Bemisia argentifolii on collard with reduced or normal leaf wax

Collard, Brassica oleracea var, acephala L., cultivars with reduced leaf wa x (i.e., glossy phenotypes) possess ovipositional antixenotic resistance to the silverleaf whitefly, Bemisia argentifolii Bellows & Perring (Homoptera : Aleyrodidae). We investigated parasitism by 2 parasitoids of B. argentifo lii reared on 2 phenotypes of the collard cultivar 'Green Glaze', differing in amount of leaf wax. When Eretmocerus sp. (Hymenoptera:Aphelinidae) para sitoids were given a choice between parasitizing whitefly nymphs on glossy and normal-wax collard, there were no significant differences in the number of parasitized nymphs on the 2 plant phenotypes. However, 4.5 times more E ncarsia pergandiella Howard (Hymenoptera: Aphelinidae) emerged from whitefl ies on glossy than on normal-wax plants. In a no-choice test, the number of Eretmocerus sp. emerging on glossy and normal-wax plants did not differ si gnificantly. In a similar no choice test, more than twice as many E. pergan diella! emerged from whiteflies on glossy collard than on normal-wax collar d. Time to 50% emergence for whiteflies and both species of parasitoids did not differ on the 2 collard types in any of the no-choice tests. We conclu de that management of B. argentifolii populations can be improved on collar d, and probably other B. oleracea vegetables, through the use of reduced le af wax cultivars that have antixenotic resistance to B. argentifolii and ha ve no detrimental effects, possibly even beneficial effects, on important w hitefly natural enemies.