Determination of some factors effecting on parasitization of European corn borer ((Ostrinia nubilalis Hübner (Lepidoptera: Pyralidae)) by Trichogramma evanescens Westwood (Hymenoptera: Trichogrammatidae) in Çukurova region of Turkey

In this study, the total developmental time, blackening time of the eggs, female and male adult longevity, life time fecundity, emergence rate, the number of emerged adult per egg mass, the number of emerged adult per parasitized egg and sex ratio of the Trichogmmma evanescens Westwood (Hymenoptera: Trichogrammatidae), the egg parasitoid of European corn borer, Ostrinia nubilalis HObner, one of the most serious pest of corn, were studied at five temperatures (15, 20, 25, 30 and 35 °C) and two humidity regimes (60±5 % and 80±5 %) under laboratory conditions. Using to these data, the life tables of the parasitoid were prepared. In addition, the effects of seven different chemicals on parasitoid mortality, emergence and parasitism rate were investigated. In the field conditions, natural parasitism rate of the parasitoid and the effects of flooding and sprinkle irrigation systems on inundative releasing of the parasitoid were determined. Depending on the temperature and humidity, the total developmental time, blackening time of the eggs, female and male adult longevity, life time fecundity, emergence rate, Ihe number of emerged adult per egg mass and the number of emerged adult per parasitized egg changed between 5.49-37.67, 2.01-12.65, 1.40-12.60 and 2.85-10.80 days 8.05-38.60 eggs, 59.76-98.74 %, 6.05-93.05 and 1.10-2.13 adult, respectively. According to the life table data, the optimum temperature for the parasitoid was 30 °C. It was found that the Bacillus thuringiensis and fenbutation oxide were harmless, cypermethrin was slightly harmful, cyfluthrin was moderately harmful, lambda^yhalothrin, azinphos-methyl were harmful to pupae stage of parasitoid; B. ûturingiensis and fenbutation oxide were harmless, alpha-cypermethrin was moderately harmful, cyfluthrin, lambda+cyhalothrin, azinphos-methyl and cypermethrin were harmful to adult of parasitoid among the chemicals tested In the field studies, the parasitism rate of T. evanescens was higher in flooding irrigation system (81.04- 84.31 %) than sprinkle irrigation (66.37-69.22 %). Natural parasitism by T. evanescens on the O. nubilalis eggs were 30.23, 46.79 and 48.78 % in the years of 1 998-2000 in the Çukurova region. Key Words: Trichogmmma evanescens, Ostrinia nubilalis, irrigation, abiotic factors, pesticides II