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

Abstract

AbstractStudies were conducted to evaluate the ability of six commercially available species of Trichogramma to parasitize eggs of tomato pinworm (TPW), Keiferia lycopersicella (Walsingham), and their potential use for biological control of TPW eggs. Of the six species, Trichogramma pretiosum Riley and Trichogramma brassicae Bezdenk parasitized the most TPW eggs (40–50%). Further studies assessed the effectiveness of T. pretiosum and T. brassicae as biological control agents for TPW eggs under controlled environmental conditions which simulated conditions that could be found during the greenhouse crop production season. Trichogramma pretiosum caused significantly higher mortality of TPW eggs than did T. brassicae at all parasitoid to host egg (P:H) ratios. Mortality caused by host feeding and stinging increased significantly with increasing P:H ratios for both species. Parasitism by T. pretiosum on TPW eggs was reduced significantly and mortality caused by feeding and stinging increased significantly at 28 °C, compared with those at 20 and 25 °C. No differences were found in parasitoid-induced mortality when T. pretiosum were offered 1-, 2-, or 3-day-old TPW eggs, but parasitoid-induced mortality was reduced significantly when parasitoids were offered 4- and 5-day-old TPW eggs. Based on these trials, a P:H ratio of between 1:1 and 10:1 is recommended for inundative releases of T. pretiosum for control of TPW on greenhouse tomatoes.