The Parasites and Predators Of Potato Aphids

The parasites and predators found attacking the Aphids,Myzus persicae, Macrosiphum solanifoliiandAulacorthum solani, during field survey work of potato Aphids in the Northern Agricultural Advisory Province during 1944 and 1945, are treated individually, receiving the proportionate attention which their occurrence merits. Aphidius avenaewas the most important primary parasite, and in potato seed growing areas, the only one; whileAsaphes vulgarisin particular, augmented byLygocerus testaceimanuscomposed the majority of hyperparasites. The effect and relative importance of both types of parasite upon the Aphid populations of the survey are discussed with their percentage figures. Predacious Syrphids includedPlatychirus manicatusandP. immarginatuswhose life-histories were previously unknown; feeding records are also given for these two, and the former species accompanied invariably byP. scufatusoccurred regularly on potatoes. More unusually, but often more effectively,Syrphus balteatusappeared. Other species were found.