EVALUATION OF 4 APHIDIINE PARASITOIDS FOR BIOLOGICAL-CONTROL OF APHIS-GOSSYPII

Four aphidiine parasitoid species (Hymenoptera: Braconidae) were evalu ated with respect to their potential to control Aphis gossypii Glover (Homoptera: Aphididae) in glasshouse cucumbers. In a laboratory experi ment thirty cotton aphids were offered to individual females for two h ours. Aphidius matricariae Haliday parasitized less than six percent o f the aphids and was ruled out as potential biological control agent. Ephedrus cerasicola Start and Lysiphlebus testaceipes Cresson parasiti zed 23 acid 26 percent of the aphids, respectively. Aphidius colemani Viereck parasitized 72 to 80 percent of the aphids. With the latter th ree species, experiments were performed in small glasshouses with cucu mbers (Cucumis sativus L. cv. 'Aramon'). As in the laboratory test A. colemani performed best; significantly more colonies were found and pa rasitization rates in the colonies were higher by A. colemani than by E. cerasicola and L. testaceipes. Because of the good correspondence b etween laboratory and glasshouse experiments, it is suggested that bad performance of an aphid parasitoid species in a simple laboratory tri al might be sufficient evidence to disregard this species for further tests.