EVALUATION OF COMMERCIALLY PRODUCED TRICHOGRAMMA SPP. (HYMENOPTERA, TRICHOGRAMMATIDAE) FOR CONTROL OF TOMATO PINWORM, KEIFERIA-LYCOPERSICELLA (LEPIDOPTERA, GELECHIIDAE), ON GREENHOUSE TOMATOES

Studies were conducted to evaluate the ability of six commercially ava ilable species of Trichogramma to parasitize eggs of tomato pinworm (T PW), Keiferia lycopersicella (Walsingham), and their potential use for biological control of TPW eggs. Of the six species, Trichogramma pret iosum Riley and Trichogramma brassicae Bezdenk parasitized the most TP W eggs (40-50%). Further studies assessed the effectiveness of I: pret iosum and I: brassicae as biological control agents for TPW eggs under controlled environmental conditions which simulated conditions that c ould be found during the greenhouse crop production season. Trichogram ma pretiosum caused significantly higher mortality of TPW eggs than di d ir: brassicae at all parasitoid to host egg (P:H) ratios. Mortality caused by host feeding and stinging increased significantly with incre asing P:H ratios for both species. Parasitism by I: pretiosum on TPW e ggs was reduced significantly and mortality caused by feeding and stin ging increased significantly at 28 degrees C, compared with those at 2 0 and 25 degrees C. No differences were found in parasitoid-induced mo rtality when I: pretiosum were offered 1-, 2-, or 3-day-old TPW eggs, but parasitoid-induced mortality was reduced significantly when parasi toids were offered 4- and 5-day-old TPW eggs. Based on these trials, a P:H ratio of between 1:1 and IO:I is recommended for inundative relea ses of I: pretiosum for control of TPW on greenhouse tomatoes.