3种新型复配剂对菜青虫的增效作用及生理生化机制

Synergisms and Physiological and Biochemical Mechanisms of three new Mixtures against Pieris rapae L.

[方法]为明确乙酰甲胺磷.噻虫嗪水乳剂、水分散粒剂和毒死蜱.噻虫嗪水分散粒剂3种新型复配剂的增效作用及增效机理,室内采用喷雾法测定了对菜青虫的增效作用;通过生化测定法研究了其对菜青虫体内羧酸酯酶(CarE)、谷胱甘肽S-转移酶(GSTs)和乙酰胆碱酯酶(AChE)活力的影响;采用石蜡切片显微观察法分析了3种复配剂处理后菜青虫中肠组织细胞的变化。[结果]3种复配剂对菜青虫都有很好的杀虫活性,处理48 h后的共毒系数分别为131.10、459.04、204.94,都表现为明显的增效作用;乙酰甲胺磷.噻虫嗪水乳剂显著抑制CarE、GSTs和AChE活力,抑制率分别为90.04%、74.98%、71.59%;乙酰甲胺磷.噻虫嗪水分散粒剂对3种酶活力的抑制率分别为72.11%、74.98%、90.60%;毒死蜱.噻虫嗪水分散粒剂则仅抑制CarE和GSTs活力,抑制率为71.16%和88.55%;3种复配剂明显影响菜青虫中肠肠壁细胞的层次结构以及肠壁细胞中的杯状细胞形状及结构。[结论]3种新型复配剂可能是通过抑制菜青虫体内关键酶活性和破坏中肠组织细胞形状和结构,进而影响其正常的消化和吸收功能,达到增效和杀虫的目的。

[Methods] In order to explicit their synergisms and mechanisms against Pieris rapae L., the synergized action against Pieris rapae L. of three new mixtures of acephate and thiamethoxam emulsion in water, acephate and thiamethoxam water dispersible granule, chlorpyrifos and thiarnethoxam water dispersible granule were determined by using spray application bioassays. The influences on the activities of carboxylesterase（CarE）, glutathione S-transferase （GSTs） and acetylcholinesterase（AChE） were tested by biochemical method. Besides, the effects on midgut cells were studied by paraffin section method. [Results] All the three mixtures showed good insecticidal activity on P. rapae L. The co-toxicity coefficient （CTCs） after 48 hours treatment were 131.10, 459.04 and 204.94, respectively, showing significant synergisms. Biochemical analysis results indicated that acephate and thiamethoxam emulsion in water and acephate and thiamethoxam water dispersible granule inhibited significantly the activities of CarE, GSTs and ACHE, the inhibition rates were 90.04, 74.98, 71.59% and 72.11, 74.98, 90.60%, respectively. However, the chlorpyrifos and thiamethoxam water dispersible granule showed inhibition only on the activities of CarE and GSTs, the inhibitions were 71.16 and 88.55%, respectively. After being treated by the three mixtures, the hierarchical structures of midgnt cell in P. rapae L. were changed, meanwhile, the shapes and structures of the goblet cells were also significantly changed. [Conclusions] Three compounded mixtures showed good insecticidal activity on P. rapae L. probably by inhibiting the activity of key enzymes, the shape and structure of goblet cells of intestinal cells, and further affecting the normal digestion and absoption functions and finally reaching synergisms and insecticidal goals.