虫酰肼对甜菜夜蛾子代种群的影响

Influence of tebufenozide on progeny population of Spodoptera exigua

为了解虫酰肼对甜菜夜蛾的作用机理,以较低剂量分别对甜菜夜蛾敏感品系幼虫和成虫进行饲毒处理,观察其对甜菜夜蛾子代种群的影响。结果表明虫酰肼是有极强后效性的杀虫剂,能降低甜菜夜蛾产卵量、化蛹率、羽化率等,提高畸形蛹、畸形蛾比例,缩短成虫寿命及产卵时间。幼虫一次饲毒后,0.2、0.4mg/kg两处理的种群趋势指数第2代较对照分别下降10.92%、26.71%,第3代下降12.16%、14.24%,说明这种影响至少可持续到第3代,且用药剂量提高,其影响加大,但孵化率与蛹重变化不明显。成虫饲毒表明,0.4、0.8mg/L两处理的种群趋势指数在第2代较对照分别下降14.18%、12.96%,第3代下降34.40%、39.24%,说明成虫饲毒对甜菜夜蛾的影响随用药次数增加而提高。甜菜夜蛾成虫寿命与虫酰肼选择频率及选择压呈负相关关系,且对雄成虫影响大于雌成虫。

In order to study the toxicological mechanism of tebufenzide, we raised poisonous diet to the larvae and adults of Wuhan susceptible strain of Spodoptera exigua. The results showed that tebufenozide was an insecticide with long aftereffect, whose effects included lower pupation and emergence rates, fewer oviposition numbers of female, higher unhealthy pupa and adult rates. Compared with the CK, the population trend index of the second generation dropped by 10.92% and 26.71% respectively after larvae were treated with 0.2 and 0.4 mg/kg poisonous diet, while the third generation reduced by 12.16% and 14.24% respectively. It indicated that such effects could last to the third generation at least and it was more obvious with higher dose. But there was no significant difference in the egg hatchability and pupa weight. The experiments of feeding adults on poisonous diet showed that the population trend index of the second generation dropped by 14.18% and 12.96% respectively, while the third generation decreased by 34.40% and 39.24% respectively. The effect on adult had positive relation to the times of using tebufenozide. The influence on adult longevity had negative relation to the selective frequency and pressure of tebufenozide, and the effect on male adult was more obvious than female.