陕西关中地区杀虫剂清园措施对桃树桃蚜种群的影响

在田间条件下研究了陕西关中地区5种杀虫剂在不同时间进行清园处理对桃树桃蚜种群的影响。结果表明,两次施药对桃蚜种群的增长均有较好的控制效果,尤以第1次施药后45d内和第2次施药后30d内,即5月6日前控制效果明显。但5月6日以后,各药剂处理的控制效果均明显下降,至第1次施药后的第60天和第2次施药后第45天,有的药剂处理已经完全失去了控制效果。早春清园对桃蚜种群的早期增长有较好的防治效果,但此时桃蚜种群数量总体偏低,直接危害并不严重,从减少用药次数和用药量的角度,早春清园预防桃蚜有无必要值得进一步试验研究。

Effects of different insecticides to Myzus persicae (Sulzer) during orchard cleaning in Guanzhong region of Shaanxi Province

The study on combination of insecticides are of great significance to extend the application life of new pesticides,slow down the resistence of target-organisms,expand control spectrum,reduce the control costs,im-prove control efficacy and enhance the environmental safety.The toxicities of eight single insecticides and their different combination to the 3rd instar nymph of Sogatella furcifera were determined with rice stem-dipping meth-od under the laboratory condition.Sixteen mixtures with cotoxicity factor more than 20 were selected qualitatively by cotoxicity factor method.Among them five mixtures,including nitenpyram and chlorpyrifos with ratio of 1∶30,imidacloprid and isoprocarb with ratios of 7∶40,7∶200,7∶400 and 7∶1 000,respectively,showed higher co-toxicity coefficient of 112.5、242.1、212.4、638.1 and 417.7,respectively.Of which the mixture of imidacloprid and isoprocarb (7∶400)showed the most significant synergism.