DIAMONDBACK MOTH (LEPIDOPTERA, PLUTELLIDAE) - PARASITISM BY COTESIA-PLUTELLAE (HYMENOPTERA, BRACONIDAE) IN CABBAGE

Cotesia plutellae Kurdjumov was evaluated as a potential biological co ntrol agent for diamondback moth, Plutella xylostella (Linnaeus), in c abbage in spring 1993 and 1994. The parasitoids were reared in a comme rcial insectary in Texas, delivered overnight via air express, and rel eased 24-48 h after receipt in cabbage fields in Northeast Florida. In 1993, only adult parasitoids were released, but adults and cocoons we re released in 1994. The numbers of C. plutellae released ranged from 456 per ha per wk in 1993 to 1,334 per ha per wk in 1994. Four consecu tive releases were made each year beginning in early February. Parasit ism of diamondback moth larvae by C. plutellae ranged from 3.6 to 10.9 %, and the level of parasitism was related to the total numbers of par asitoids released. C. plutellae parasitoids were complimentary to the naturally occurring parasitoid Diadegma insulare (Cresson), and the co mbined mean seasonal parasitism of diamondback moth exceeded 34% in so me fields. There was no evidence that C. plutellae became established in the general area although > 124,000 parasitoids were released over the 2-year test period.