氰戊菊酯和甲氰菊酯对棉铃虫的亚致死效应

本文通过饲喂法测定了氰戊菊酯、甲氰菊酯两种拟除虫菊酯杀虫剂亚致死剂量(LC1与LC50)对棉铃虫3龄幼虫拒食、体重、生长发育以及驱避作用的影响。结果表明,各处理棉铃虫3龄幼虫,取食量均低于对照。处理后48h,LC50剂量以氰戊菊酯拒食活性较高,拒食率为38.65%,且LC50剂量的各处理与对照差异显著。所有处理对棉铃虫幼虫—蛹、蛹—成虫的存活率都有影响。药剂处理后,幼虫的历期延长,幼虫的化蛹也受到影响,出现畸蛹,但各处理畸蛹率均低于15%。亚致死剂量杀虫剂对棉铃虫的生长发育、幼虫体重及蛹重都有抑制作用。在LC1与LC50剂量下,两种药剂对棉铃虫也表现出驱避作用。处理48h,氰戊菊酯LC1与LC50剂量的驱避率分别为76.25%与98.75%。这些研究结果显示,低剂量的拟除虫菊酯对棉铃虫生物学方面存在不良影响。

Sublethal Effects of Fenvalerate and Fenpropathrin on the Cotton bollworm

The effect of sublethal concentration (LC1 and LC50) of fenvalerate and fenpropathrin on the 3 d larva cotton bollworm’s antifeedence, body weight, development and repellent was measured using the feeding method. The results showed that all the insecticides used had antifeedent activity, and the content consumed by those treated were lower than those of untreated. To those treatment with LC50, fenvalerate showed higher antifeedent activity to the bollworm in 48 hour post-treatment, the antifeedent rate was 38.65%, and all treated with LC50 show significant difference to contrast. All treated have effect to the survival rate between larva to pupa and pupa to adult. The influence of pesticides on the bollworm include the prolonged period of larva and deformed pupa , but rate of the deformed pupa was lower than 15%. The sublethal concentration showed inhibition to the development, weights of larva and pupa of the bollworm. Under LC1 and LC50, all pesticides that were used showed repellent to the bollworm. After treatment 48h, the LC1 and LC50 of fenvalerate was 76.25% and 98.75% respectively. All results showed that pyrethroids at low levels have negative effect on the biology of cotton bollworm.