哒嗪硫磷对拟除虫菊酯类杀虫剂植物表面降解的影响

在棉花茶叶大田用哒嗪硫磷分别与3种拟除虫菊酯杀虫剂混合喷施,哒嗪硫磷显著促进氯氰菊酯、溴氰菊酯和氰戊菊酯在2种植物表面的降解。施药后经过1个夏季光照日,混用比未混用处理的降解率在棉花上增大5.1—29.7%,在茶叶上增大19.0—32.2%。这种加速降解的效应随哒嗪硫磷浓度增大而加强。哒嗪硫磷的混用也影响3种拟菊酯杀虫剂在棉叶上的原始沉积量,使之降低9.8—27.2%。

Stimulated Effects of Pyridaphenthion on Degradation of 3 Pyrethroid Insecticides on Plant Foliage

Mixture of cypermethrin, deltamethrin and fenvalerate with pyridaphenthion were sprayedon tea or cotton fields in summer of 1991 and 1992. The results of residue analysis showed that1 or 2 sunny days after application, the degradation of 3 pyrethroid insecticides on foliage of bothplants were accelerated significantly by pyridaphenthion. The decay percentage of cypermethrin,deltamethrin and fenvalerate were increased by 15. 2-29. 7%, 14.4-18. 6% and 5. 1-21.1% oncotton, 19.0-32. 20%, 20. 1-26.5% and 21.4-31.7% on tea, respectively. These stimulatingeffects of pyridaphenthion on 3 pyrethroid insecticides were enhanced with the increase of concen-tration of pyridaphenthion in the range of 250-1000ppm. The deposition of 3 the pyrethroid in-secticides on foliage was reduced significantly by pyridaphenthion on cotton, but not on tea.