اختلاط سموم و اثرات سینرژیستی: با تمرکز بر مدیریت تریپس پیاز Thrips tabaci (Thys.: Thripidae)

The onion thrips, Thrips tabaci, is the most important onion pest around the world, causing serious damage to the family Alliaceae and Brassicacea. Although the integrated pest management approach has always been proposed for pest control, the onion thrips management has mainly relied on chemical control, and other approaches have not been operationally advanced. Resistance of onion thrips to organophosphorus, carbamate and pyrethroid insecticides have been reported in most parts of the world. Combination use of pesticides with the different mode of action has been suggested as an effective approach to slow the evolution of resistance. In this research, the effects of different pesticides in individual (eight treatments) and mixtures experiments (seven treatments) were investigated in a randomized complete block design with three replications in onion farm located in Esfarayen, Khorasan province, Iran in May 2018. The pesticide field experiments were carried out with individual treatments including Efforia (150, 200, 250 ml per hectare), Teppeki (150 and 250 g per hectare), Metasystox (1000ml per hectare) and Proclaimfit (150 g per hectare) and mixture treatments including Efforia+Teppeki, Efforia+Proclaimfit, Efforia+Metasystox. To determine the efficacy of pesticides the sampling was carried out during two weeks after spraying,. Further experiments were done to evaluate the synergistic effects of pesticide mixtures with a surfactant and vegetable oil. According to the results, pesticide mixtures in all experiments caused a higher mortality than the individual treatments in onion thrips, so that the mixture treatments of Efforia+Teppeki, Efforia+Proclaimfit, Efforia+Metasystox caused 63, 67 and 66 percent mortality after two weeks after treatment, respectively. The results of synergists study indicated that vegetable oil was more effective than surfactant and caused 85% mortality in onion thrips after two weeks after treatments. Therefore, the combination of pesticides with the different mode of action and vegetable oils was recommended for effective thrips management.