Individual toxicity of flupyradifurone and flonicamid and their combination with an organic fertilizer on nymphal stage of greenhouse whitefly Trialeurodes vaporariorum Westwood (Hem: Aleyrodidae) under laboratory condition
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عنوان دوره: سومین کنگره بین المللی حشره شناسی ایران
نویسندگان
Department of Plant Protection, Faculty of Agriculture, Urmia University, Urmia, Iran,
چکیده
Soheyla Rasouli Bagtash and Orouj Valizadegan
Valizadegan@gmail.com
Trialeurodes vaporariorum Westwood (Hem: Aleyrodidae) is a widely distributed pest of ornamental and horticultural plants. It is usually controlled by frequent pesticide sprays. A recent survey has shown that farmers in Urmia County claimed better pest control by application of pesticides mixed with organic fertilizers. Therefore, a research was conducted to test the hypothesis. T. vaporariorum adults were obtained from a colony established on poinsettia plants at greenhouse of the Urmia University (originally collected from snap bean fields). They were reared at 25 ± 2 °C, 65 ± 5% RH and 16:8 h L:D. Newly emerged adults were paired and sexed in clip cages (inner diameter = 2.5 cm). After 10 h, adults were removed and about 100 eggs were allowed to develop under the mentioned conditions. The effects of flupyradifurone (Sivanto) and flonicamid (Teppeki) pesticides were evaluated individually and in combination with smellvert organic fertilizer, on different nymph instars of the whitefly with leaf dipping method. Sivanto concentrations were 100, 250, 500, 1000 and 1500 ppm, and concentrations of Teppeki were 50, 100, 200, 300 and 400 ppm, respectively. The LC50 of Sivanto (systemic toxicity) and Teppeki (digestive toxicity) on 1, 2-3 and 4 nymph instars of the pests were calculated as 487.079, 598.749 and 667.378 ppm and 3998.912, 16545.040 and 7289.528 ppm over period of 24 h, respectively. Moreover, mortality caused by Sivanto and Teppeki individual application on 1, 2-3 and 4 nymph instars were obtained as 28.24, 27.77 and 26.88% and 42.19, 38.63 and 36.02%, respectively. However, the Sivanto + Smellvert and Teppeki + Smelvert treatments on 1, 2-3 and 4 nymph instars of the pest had mortalities equal to 32.03, 29.84 and 28.13% and 50.08, 43.16 and 39.11%, respectively. It is concluded that digestive toxicity of Teppeki in combination with smellvert fertilizer increased on greenhouse whitefly nymphs probably due to the increased insect feeding stimulated by organic fertilizer and, therefore, causing more pesticides uptake by the nymphs. Although findings verified the hypothesis reflected by farmers, nevertheless, complementary field experiments are required to draw any general conclusion.
Valizadegan@gmail.com
Trialeurodes vaporariorum Westwood (Hem: Aleyrodidae) is a widely distributed pest of ornamental and horticultural plants. It is usually controlled by frequent pesticide sprays. A recent survey has shown that farmers in Urmia County claimed better pest control by application of pesticides mixed with organic fertilizers. Therefore, a research was conducted to test the hypothesis. T. vaporariorum adults were obtained from a colony established on poinsettia plants at greenhouse of the Urmia University (originally collected from snap bean fields). They were reared at 25 ± 2 °C, 65 ± 5% RH and 16:8 h L:D. Newly emerged adults were paired and sexed in clip cages (inner diameter = 2.5 cm). After 10 h, adults were removed and about 100 eggs were allowed to develop under the mentioned conditions. The effects of flupyradifurone (Sivanto) and flonicamid (Teppeki) pesticides were evaluated individually and in combination with smellvert organic fertilizer, on different nymph instars of the whitefly with leaf dipping method. Sivanto concentrations were 100, 250, 500, 1000 and 1500 ppm, and concentrations of Teppeki were 50, 100, 200, 300 and 400 ppm, respectively. The LC50 of Sivanto (systemic toxicity) and Teppeki (digestive toxicity) on 1, 2-3 and 4 nymph instars of the pests were calculated as 487.079, 598.749 and 667.378 ppm and 3998.912, 16545.040 and 7289.528 ppm over period of 24 h, respectively. Moreover, mortality caused by Sivanto and Teppeki individual application on 1, 2-3 and 4 nymph instars were obtained as 28.24, 27.77 and 26.88% and 42.19, 38.63 and 36.02%, respectively. However, the Sivanto + Smellvert and Teppeki + Smelvert treatments on 1, 2-3 and 4 nymph instars of the pest had mortalities equal to 32.03, 29.84 and 28.13% and 50.08, 43.16 and 39.11%, respectively. It is concluded that digestive toxicity of Teppeki in combination with smellvert fertilizer increased on greenhouse whitefly nymphs probably due to the increased insect feeding stimulated by organic fertilizer and, therefore, causing more pesticides uptake by the nymphs. Although findings verified the hypothesis reflected by farmers, nevertheless, complementary field experiments are required to draw any general conclusion.
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