棉蚜对吡虫啉抗性的初步研究

用吡虫啉对棉蚜进行室内抗性筛选,用药处理25次后抗性是筛选前的20.03倍;2007年对田间棉蚜进行抗性调查,发现不同地区种群对吡虫啉的抗性差异显著,江苏南京种群最为敏感,河南安阳、山东泰安和北京地区棉蚜与之相比,抗性分别为2.21、7.63和9.53倍;抗、感品系解毒酶活力分析发现,抗性品系的谷胱甘肽S-转移酶活性增加很少(比活力1.12倍),但酯酶活力显著高于敏感品系(比活力1.71倍);增效试验结果表明,顺丁烯二酸二乙酯(DEM)在抗、感品系中对吡虫啉均没有明显的增效作用,而磷酸三苯酯(TPP)和增效醚(PBO)虽然在敏感品系中对吡虫啉的增效作用较小(SR 1.24和1.29),但在抗性品系中的增效作用显著增高(SR 2.13和1.74);此外还发现,吡虫啉处理可提高棉蚜群体的酯酶活力。由此认为,棉蚜至少具有对吡虫啉产生中等水平抗性的风险,其抗性可能是由于棉蚜的酯酶和P450单加氧酶的解毒能力提高所致。

Primary Studies on Resistance of Aphis gossypii to Imidacloprid

The cotton aphid,Aphis gossypii Glover,was continuously selected with imidacloprid in the laboratory,and its resistance was found to increase by 20.03-fold after treatment for 25 times.Field survey revealed that the imidacloprid resistance in cotton aphid varied dramatically with geographical populations.Nanjing aphid population was the most susceptible,and the relative resistance ratio of the aphids from Anyang,Taian and Beijing were 2.21,7.63 and 9.53,respectively.Analysis of detoxification enzymes demonstrated that the glutathione-S-transferase was similar in activity in the resistant and the susceptible strain(activity rate R/S 1.12 folds).However,the activity of esterase in resistant strain was significantly higher than that in the susceptible strain(1.71 folds).Synergism tests showed that DEM had little synergistic effect on imidacloprid in both resistant and susceptible strains(synergism ratio,SR 1.11 and 0.95,respectively).However TPP and PBO showed obvious synergism,and it was more significant in the resistant strain(SR 2.13 and 1.74,respectively)than that in the susceptible strain(SR 1.24 and 1.29,respectively).In addition,treatment with imidacloprid could obviously enhance the esterase activity of aphid populations.Thus,it was concluded that cotton aphid has the potential at least to develop moderate resistance to imidacloprid.The enhanced esterase and cytochrome P450-monooxygenases detoxification might contribute to the imidacloprid resistance in the pest.