Integration of <I>Trichogramma evanescens</I> Westwood and <I>Bacillus thuringiensis</I> Subsp. Kurstaki for Controlling Lepidopterous Pests in Tomato Fields

Abstract

The efficacy of the egg parasitoid Trichogramma evanescens (Hymenoptera: Trichogrammatidae) and Bacillus thuringiensis subsp. kurstaki for controlling Helicoverpa armigera (Hubner) and Chrysodeixis chalcites (Esper) (Lepidoptera: Noctuidae) in tomato fields was investigated. Single and combined treatments of T. evanescens and the bioinsecticide were tested. Control methods were carried in plant protection research station, at Qaha, Qalyubia Governorate during summer plantations, 2008. The efficacy of these control methods was recorded on the basis of mean number of larvae/plant and reduction percentage of the larvae during six weeks from each application. Based on reduction percentages in the number of H. armigera and C. chalcites larvae, the efficacy of the tested treatments could be descendingly arranged as follows T. evanescens + B. thuringiensis, B. thuringiensis and T. evanescens . The corresponding values were 90, 82.9, and 81.2 % for the above treatments respectively, against H. armigera and 86.3, 59.3 and 57.5% for the above treatment respectively, against C. chalcites. The result also shows that there was no negative interaction between B. thuringiensis application and T. evanescens releases. By comparing the ratio of damaged caused to tomato fruits by all lepidopterous larvae complex feeding, mean weight of healthy fruits of yield and mean weight of single healthy and infected fruit after the above mentioned treatments, the integrated treatment (T. evanescens + B. thuringiensis ) was the most effective followed by B. thuringiensis and T. evanescens.