紫外吸收剂抑制阿维菌素光解及对小菜蛾防治的增效作用

Inhibition of UV-absorbents on avermectin photodegradation and their enhanced control on diamondback moth(Plutella xylostella).

利用高效液相色谱法测定了紫外吸收剂在一定紫外光强度(420 lx,254 nm)下对阿维菌素光解速率的影响,同时测定了其与阿维菌素混用对小菜蛾的毒力和田间防效。结果表明,加入紫外吸收剂UV-73和UV-75后,可以显著地提高阿维菌素的光稳定性,光解4 h,阿维菌素的分解率分别降低76.74%和77.46%;光解8h,阿维菌素的分解率分别降低37.92%和47.09%;光解16 h,阿维菌素的分解率分别降低33.55%和48.55%;光解24 h,阿维菌素的分解率分别降低23.57%和42.09%。室内生物测定结果表明,紫外光下加入紫外吸收剂UV-73和UV-75后,阿维菌素对小菜蛾的增效比值分别为1.59和1.74。田间药效结果也表明,与紫外吸收剂混用的阿维菌素对小菜蛾的防效明显高于单用。

By the method of high performance liquid chromatography, the decomposition of avermectin after adding ultraviolet absorbents was studied under the ultraviolet intensity of 420 lx. The results showed that under the ultraviolet, the decomposition rate of avermectin after adding UV-73 and UV-75 decreased 76.74% and 77.46% after 4 hours, 37.92% and 47.09% after 8 hours, 33.55% and 48.55% after 16 hours, and 23.57 % and 42.09 % after 24 hours, respectively. The synergism ratios of avermectin with UV-73 and UV- 75 on diamondback moths in laboratory were 1.59 and 1.74, respectively, and the enhanced control effects of UV-73 and UV-75 were also higher than that of single avermectin application in the field.