Effect of some insecticides on the immature stages of the egg parasitoid Trichogramma evanescens West. (Hym., Trichogrammatidae )

The effect of five  insecticides, Profect (w.p.), CAPL- 2,  Lambda-cyhalothrin, Spinosad, and Fenitrothion ( Sumithon)  on the immature stages of the first and the second generations of the egg parasitoid Trichogramma evanescens was studied in laboratory at 25 ± 1 ⁰C, 65± 5% R.H. and 12:12 L:D. The study was carried out on parasitized eggs one, two, four and eight days post parasitism. Results showed that: 1) Longevity of the emerged parasitoid was affected by the tested insecticides. The recorded values of the adult longevity emerged from treated eggs ranged from 12 hrs to 7 days ( for females ) and from 12 hrs to 4 days (for males). Treating eggs with chemical insecticides caused death of the emerged adults within few hours post emergence when the treatment was carried out 4 days post parasitism or one day before adult emergence. 2). The number of host eggs turned to black (the parasitoid larvae developed to pupae) varied according to timing of treatment. 3). Adult emergence rate varied according to the used insecticide, the parasitoid stage and the generation. 4) No parasitoids emerged from parasitized eggs treated with CAPL-2.  5).
There was no emergence for the parasitoid treated with Lambda-cyhalothrin, spinosad, and fenitrothion (Sumithon) one, two or four days after parasitism. However, emergence was recorded with very low percentages when the eggs were treated 24 hrs before parasitoid emergence. 6) Female percentage slightly decreased in the adults emerged from paeasitized eggs treated with chemicals.