Composition and relative abundance of parasites associated with aphid populations on strawberry in southern California [Chaetosiphon fragaefolii]

Four primary parasites and seven secondary parasites (hyperparasites) were reared from mummies of five species of aphids collected from winter plantings of strawberries in southern California in 1981 and 1982. In order of abundance, the primary parasites were Lysiphlebus testaceipes Cresson, Aphelinus semiflavus Howard, Aphidius urticae Haliday, and Ephedrus californicus Baker. L. testaceipes accounted for 47.8 and 77.1% of all primaries in 1981 and 1982, respectively, and was reared most commonly from the strawberry aphid, Chaetosiphon fragaefolii (Cockerell), in 1981 (56.3%) and from the melon aphid, Aphis gossypii Glover, in 1982 (74.5%). Dendrocerus aphidum (Rondani) and Alloxysta magourae "complex" were the most common secondary parasites, accounting for 34.6 and 19.2% of all secondaries, respectively, in 1981 and for 55.8 and 23.4% in 1982. C. fragaefolii was the most common aphid present both years, reaching damaging populations in 1982 despite the parasite activity.