棉铃虫核型多角体病毒与化学杀虫剂和卵磷脂混用的增效作用

Synergism of Helicoverpa armigera nucleopolyhedrovirus in combinations with chemical insecticides and lecithin

棉铃虫核型多角体病毒 (HaNPV)分别与三氟氯氰菊酯、溴氰菊酯、氰戊菊酯、灭净菊酯、灭多威、辛硫磷、甲基对硫磷和乙酰甲胺磷等化学杀虫剂混合饲喂棉铃虫幼虫 ,统计致死中浓度LC50 ,计算增效比 ,测定虫体内与抗性有关的三种重要酶 :多功能氧化酶 (MFO)、羧酸酯酶 (CarE)、乙酰胆碱酯酶 (AChE)的活性。研究大豆卵磷脂对HaNPV致病性的影响。结果表明 :HaNPV与化学杀虫剂混合饲喂抗性棉铃虫 ,生测统计增效比均大于 1 0 ,特别是病毒与甲基对硫磷混用 ,增效比更是达到 3 53,表现出良好的增效作用。混剂感染抗性棉铃虫 ,虫体内MFO的活性比化学杀虫剂单用时降低 3～ 12倍 ,CarE和AChE的活性也比化学杀虫剂单用时低 ,HaNPV明显抑制了化学杀虫剂对MFO和CarE的诱导作用。HaNPV与大豆卵磷脂混用 ,提高了HaNPV对棉铃虫的感染致死率 ,缩短了致死中时间 (LT50 )。

Third instar larvae of Helicoverpa armigera were fed on artificial diet mixed with combinations of H.armigera nucleopolyhedrovirus (HaNPV) and insecticides——cyhalothrin, deltamethrin, esfinualerate, mijinthrin, methomyl, phoxim, methylparathion and acephate respectively. Mortalities were observed,and LC 50 values and the synergic ratio were determined. The activities of three enzymes (Mixed function oxidase, MFO; Carboxylesterase, CarE; Acetylcholinesterase, AChE) in relation to the pest resistance to insecticides were also detected. In addition,enhancement of HaNPV infectivity by soybean lecithin was revealed. The results showed that combination of HaNPV and each of the insecticides was more effective than HaNPV or insecticides alone, all the synergic ratios were mere than 1 0, especially synergic ratio of HaNPV methylparathion treatment arrived at 3 53. The activities of MFO in resistant H.armigera larvae treated with mixtures of HaNPV and insecticides decreased 3～27 times as compared to insecticide treatments alone. The activities of CarE and AChE in the resistant larvae treated with the mixtures were lower than that with insecticides alone as well. NPV inhibited the increase of MFO and CarE activity induced by insecticides. Lecithin enhanced the infectivity of HaNPV against H.armigera larvae, the LT 50 value of HaNPV was shorten when the lecithin was combined.