Pesticide compatibility with Aphidius colemani (Hymenoptera: Braconidae) for biological control applications in greenhouse production systems

Aphidius colemani (Viereck) is a commercially available parasitoid used in augmentative and banker plant biological control applications. The parasitoid is used for management of the green peach aphid (Myzus persicae), the melon aphid (Aphis gossypii), and the tobacco aphid (Myzus nicotianae). For successful biological control, information is needed regarding the use of A. colemani in conjunction with greenhouse pesticides to control for other aphid pests, mealybugs, spider mites, whiteflies, and fungi. Pesticide compatibility was evaluated at medium and high label rates for 12 insecticides and 2 fungicides. Ornamental pepper (Capsicum annuum ‘Black Pearl’) plants were used for systemic and contact pesticides. Soil-applied insecticides were used as a drench on potted pepper plants and infested with 10 M. persicae nymphs. Drenched plants were exposed to A. colemani, caged, and measured for direct aphid mortality, percent aphid parasitism, and percent parasitoid emergence over time until A. colemani adults were observed approximately 10-14 days after treatment (DAT). For foliar-applied pesticides, pepper leaves were dipped in pesticide solution and air dried. Treated leaves were hydrated, placed in petri dishes containing a water wick and honey streak, and 5 A. colemani adults were introduced per dish. Experiments were replicated 10 times and parasitoid mortality was measured at 6, 12, 24, and 48 h post treatment. Results were classified by IOBC guidelines as harmless (<30% mortality within 48 h), slightly harmful (30-79% mortality within 48 h), moderately harmful (80-98% mortality within 48 h), and harmful (>99% mortality within 48 h).