The susceptibility of Aphelinus mali (Haldeman), a parasitoid of Eriosoma lanigerum (Hausmann), to pesticides used in apple orchards in the Elgin area, Western Cape Province, South africa
Aphelinus mali is the most important biological control agent of Eriosoma lanigerum, a serious pest of apples. The effects of 14 insecticides and 10 fungicides on the adult stage of the parasitiod, A. mali, were investigated under laboratory conditions. Some insecticides were also screened for their effect on the emergence of adult wasps from mummified aphids. Most chemicals were highly toxic to the adult wasps which succumbed within 24 h of exposure to the chemicals. Exceptions were endosulfan, two insect growth regulators and all fungicides tested. Percentage emergence of adult wasps from the mummies was high after treatment with all chemicals tested. However, in the case of chlorpyrifos more than 60% of the parasitoid adults died soon after emergence, while nearly 30% of the adults died soon after emerging from mummies treated with carbaryl (XLR Plus) and fenthion.