Survey of Parasitismic Effect of Two Species of Trichogramma on Eggs of Tuta absoluta under Effect of Pesticides

Due to the fact that Tuta absoluta is one of the most important pests of tomato and causes damage, therefore to use less risk insecticides for the environment, consumers and natural enemies, in the study, the effects of, abamectin, emamectin benzoate, acetamiprid, and flubendiamide were tested against T. brassicae and T. evanescens of natural enemies of T. absoluta in laboratory conditions of Arak Agricultural Research Center in 2018. Parasitoids were reared on the angoumois grain moth, Sitotroga cerealella (Lepidoptera: Gelechiidae) eggs in the laboratory under the controlled conditions of 25 ± 1 °C, 60 ± 10% RH, and a photoperiod of 16:8 h (L: D). The comparison test of the parasitism of the two species was performed by t-test and in 10 categories in a plastic glass. LC25 of pesticides in tests were used. The experiments on LC25 effect of each pesticide on wasps survival were performed by vial assay and completely randomized design in 5 replications and in each replications 10 female wasps. Wasps were exposed to this concentration for 24 hours. Control treatment was distilled water. In order to investigate parasitism rate of lived wasps, experiments were conducted in 3 replications in each replications were 5 wasps that for 48 hours were placed exposed to150 eggs of Tuta absoluta in cylindrical containers. Completely randomized design to factoriel method was conducted. The mortality rate was recorded daily and the rate of parasitism reduction was calculated. Corrected mortality rate for abamectin, emamectin benzoate, acetamiprid and flubendiamide with host of T. absoluta were 26.67, 20, 13.33 and 13.33% for T. brassicae, respectively, and for T. evanescens 20, 20, 13.33 and 6.67 percent. The rate of reduction of parasitism in the treatment of abamectin, emamectin benzoate, acetamiprid and flubendiamide for T. brassicae were 25.12, 18.71, 13.3 and 11.81% respectively, and for T. evanescens were 24.18, 19.2, 15 and 10.84% respectively. Based on our results, flubendiamide showed selectivity and it can be used as an effective tool for integrated pest management programs of tomato leaf miner.