Effects of pesticides on the parasitic wasp, Aphelinus mali

Most of the insecticides, except the insect growth regulators, were highly toxic to adult A. mali within the first 24 hours after exposure. Endosulfan used for the control of woolly apple aphid (WAA) was found to be less toxic to the parasitic wasp than chlorpyrifos and vamidothion, which are also used for this purpose. Therefore, endosulfan would be more suitable than chlorpyrifos or vamidothion as a corrective spray in integrated programs designed to give maximum biological control of WAA populations. The two insect growth regulators, flufenoxuron and fenoxycarb, which are both used against codling moth had minimal effects on A. mali. The fungicides caused low mortality of A. mali within the first 48 hours after exposure to the chemical residues, but thereafter the corrected percentage mortality increased to between 50% and 75% for captab, copper oxychloride, bupirimate, kresoxim-methyl and benomyl. Fenarimol produced a corrected percentage mortality of 23% after 48 hours, which increased slightly, to 32% after 72 hours. These results closely resemble those of other researchers.