Study on the effects of aqueous neem seed extract on the leaf damage and longevity of 2nd instar nymph and adult stages of Retithrips syriacus

Neem extract has been used as a botanical pesticide with a long history in the world. In this study, we compared lethal and antifeedant effects of 1, 2, 5 and 10 percent of neem seed water extract with 1, 2, 3 and 5 ml/litter of a neem based pesticide with 1% Azadirachtin (NicoNeem) on Retithrips syriacus. This experiment was conducted with a completely random design with 9 treatments and one control each with four replications. Mortality of the insect was recorded and damage points were counted as damage criteria. The obtained data were analyzed using R ver. 2.15.1 statistical softawre. Both water extract and neem-based pesticide reduced longevity of insect significantly. Two of the most effective treatments of water extracts at 5 and 10 percent reduced longevity of adult insect respectively to 3.03 and 3.34 and nymphs to 3.36 and 2.82 in comparison with the control (7.6 and 8.32). Two high concentrated of neem-based pesticide (3 and 5ml/Li) also reduced longevity of adult respectively to1.54 and 1.52 and nymphs to 2.14 and 1.64 compared with those of control (9.15 and 7.25). In comparing antifeedant effects, all neem-based pesticide treatments showed significantly higher effect in comparison with the water extracts. Based on thes eresults, we can conclude that in thirips population management neem-based pesticides are the most effective products to reduce longevity and leaf damage of thrips on the plants.