棉红铃虫的自然耐药性及其代谢机制

NATURAL TOLERANCE TO INSECTICIDES OF PECTINOPHORA GOSSYPIELLA(SAUNDERS) AND ITS METABOLIC MECHANISM

棉红铃虫(Pectinophora gossypiella Saunders)安庆种群的漫行期滞育幼虫,对溴氰菊酯和敌敌畏的LD_(50)值(ug/g)分别为该种群第一代田间花虫(4龄幼虫)的9.12倍和3.08倍。增效测定发现,增效醚(Pb)和磷酸三苯脂(TPP)对溴氰菊酯均有显著的增效作用,对漫行期滞育幼虫的致死率较一代田间花虫略强。漫行期滞育幼虫中肠、脂肪体、体壁及整体的酯酶活力分别是第一代田间花虫的1.73,2.05,2.06和1.83倍,且可分别被磷酸三苯脂活体抑制83.4％,29.7％,49.6％和67.7％。说明漫行期滞育幼虫体内具有较高的解毒代谢作用,是棉红铃虫自然耐药性的原因之一。

Bioassay on Anqing field strain of pink bollworn (pectinophra gossypiella)(Anhui Province) showed that the LD_(50)values of deltamethrin and dichlorphos for the diapausing larvae at the wandering stage were 9.12-and 3.08-fold greater, respectively, than those for 4th instar larvae infecting flowers. Deltamethrin was greatly synergised by pb and TPP, but their synergism was slightly higher in diapausing than in nondiapausing larvae. Enzyme activity determination indicated that esterase activity in the midgut, fat-body, cuticle and the whole body of the diapausing larvae at the wandering stage 1.73, was 2.05-, 2.05-and 1.83-fold, respectively, as high as that of 4th instarlarvae infecting flowers and was inhibited 83.7, 29.7, 49.6, and 67.7％, respectively, by TPP in vivo. Such results suggest that one of the causes for the natural insecticide tolerance in P.gossypiella might be that a relatively high detoxification metabolism exists in diapausing larvae at the wandering stage.