2,4-D二甲胺盐对莲草直胸跳甲生存和繁殖的影响

为探究除草剂在防治喜旱莲子草(Alternanthera philoxeroides)的过程中对其天敌昆虫的影响,采用不同浓度的2,4-D二甲胺盐浸叶处理的喜旱莲子草饲喂莲草直胸跳甲,连续饲喂7d后,考察了莲草直胸跳甲的繁殖、存活和发育情况。结果表明,2,4-D二甲胺盐可显著降低莲草直胸跳甲成虫的取食量,且抑制作用随药剂浓度升高和取食时间延长而显著增强;较高浓度(1.72～3.44g·L~(-1))的2,4-D二甲胺盐还会导致莲草直胸跳甲雌成虫存活率和产卵量的明显降低,卵孵化率、幼虫存活率和蛹羽化率也显著降低。可见,高浓度(1.72～3.44g·L~(-1))的2,4-D二甲胺盐对莲草直胸跳甲的生长发育和繁殖有显著不利影响,在防治喜旱莲子草时,应将2,4-D二甲胺盐的施用浓度控制在0.22～0.86g·L~(-1)内。

Effects of 2,4-D Dimethylamine Salt on Survival and Reproduction of Agasicles hygrophila

To investigate the effects of herbicides on its natural insect enemies in controlling alligatorweed(Alternanthera philoxeroides),the flea beetles(Agasicles hygrophila) were fed alligatorweed treated with different concentrations of 2,4-D dimethylamine salt by using the leaf dipping method for 7 days,and then the reproduction,survival and development of A.hygrophila were studied.Results showed that exposure to 2,4-D dimethylamine salt could remarkably reduce the food consumption of adult A.hygrophila,and the inhibition effect became more significant with increasing the concentration of 2,4-D dimethylamine salt and extending the feeding time.After feeding on alligatorweed contaminated with 2,4-D dimethylamine salt at high concentration(1.72-3.44 g·L~(-1)),the survival rate and fecundity of female adult decreased significantly,while the egg hatching rate,larval survival rate and pupal eclosion rate of A.hygrophila also decreased markedly.It is indicated that high concentration of 2,4-D dimethylamine salt(1.72-3.44 g·L~(-1)) had significant adverse impacts on the development and reproduction of A.hygrophila.It is suggested that the applied concentration of 2,4-D dimethylamine salt should be restricted between 0.22 and 0.86 g·L~(-1) in controlling alligatorweed.