Evaluation of susceptibility of the first instar nymphs and adults of Trialeurodes vaporariorum (Hemiptera: Aleyrodidae) to neonicotinoid insecticides under laboratory conditions

The greenhouse whitefly, Trialeurodes vaporariorum (Westwood), has been well established in the greenhouse ecosystems and is one of the most important pests on various greenhouse crops worldwide. Because of its high fecundity and resistance to commonly used pesticides, a study was conducted to examine the effectiveness of conventional insecticides of neonicotinoid compounds. In this study, the whiteflies on the ornamental plant genus Gerbera were collected from a greenhouse in the city of Mahalat and reared on tobacco under laboratory conditions at ۲۵ ± ۲ºC and ۶۰ ± ۵% Rate of humidity (RH) and a photoperiod of ۱۶: ۸ h (L: D). The toxicity of three neonicotinoid insecticides including imidacloprid SC۳۵% (Confidor), thiamethoxam SC۲۱.۶% (Actara) and dinotefuran SG۲۰% (Starkle) on the adults and first instar nymphs of T. vaporariorum, was evaluated using leaf dipping bioassay method. The susceptibility of adults was assessed at ۲۴ hour post-treatment. The LC۵۰ values of imidacloprid, thiamethoxam and dinotefuran for adults were ۱۳۰.۴۸, ۵۲.۸۹ and ۹۳.۵۵ ppm (a. i.) respectively. The mortality of immature stages was assessed at ۷۲ hour post-treatment. The LC۵۰ values of imidacloprid, thiamethoxam and dinotefuran for the first instar nymph were ۲۶.۶۵, ۱۲.۶۲ and ۱۵.۴۸ ppm (a. i.) respectively. The results suggest that all insecticides are more toxic on first instar nymphs than adults while thiamethoxam has the highest toxicity. The insecticides dinotefuran and imidacloprid can effectively control the adults and first instar nymphs as well.

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سفیدبالک گلخانه ، ایمیداکلوپرید ، دینوتفوران ، تیامتوکسام ، زیستسنجی