The occurrence and population fluctuation of natural enemies (predators and parasitods) associated with Brachycaudus schwartzi.(Börner) were studied on peach (Prunus persica). Two twigs 25 cm long were sampled every 15 days in 10 plants from August 1994 to July 1995 and taken to the laboratory for assessing the incidence of aphids and their natural enemies. Over the period of greatest aphid occurrence, predators of the families Coccinellidae (six species) and Syrphidae (seven species) and the parasitoid Aphidius colemani Viereck (Aphidiidae) were observed. Predators occurred at higher incidence from August to December, 1994, where occurrence of B. schwartzi was greatest. Among the species of Coccinellidae surveyed, the occurrence of Scymnus (Pullus) argentinicus (Weise) was higher and represented 43,9% of the total coccinellids surveyed. The coccinellid population peaked in October. The species Allograpta neotropica Curran (Syrphidae) showed highest occurrence (86,7%) among Syrphidae and its population peaked in September as did A. colemani.
Insecta; aphid; natural enemies; biological control
