不同虫龄甜菜夜蛾幼虫实验种群对核型多角体病毒的敏感性

Infective Sensitivity of Different Instar Host Larva Population to Spodoptera exigua Nuclear Polyhedrosis Virus (SeNPV)

利用经稀释10-1和10-3的甜菜夜蛾核型多角体病毒(SeNPV)初提液,对甜菜夜蛾各龄幼虫不同实验种群进行饲毒,以研究不同龄期宿主幼虫对SeNPV的敏感性差异.结果表明,宿主幼虫虫龄与其对病毒的敏感性呈显著负相关,虫龄越小,对病毒的敏感性越高.低浓度病毒(8.24×104PIB/mL)感染1～3龄幼虫,患病率达89%以上,患病个体死亡率达94%以上.高浓度病毒(8.24×106PIB/mL)能导致89.6%以上高龄幼虫死亡.SeNPV导致宿主幼虫死亡的时间相对较短.Weibull模型可较好地拟合各试验结果.

In laboratory, each instar host larva population is fed different dosages of Se NPV in order to see their different infective sensitivity to SeNPV. Th e result is that, with host larva instar decreasing,their infective sensitivity increases gradually. In 1^(st), 2^(nd) and 3^(rd) instar, 89% host larv a can be infected even fed to comparative lower dosage of 8.24×10~4 PIB/mL and then over 94% of diseased host larva have been dead. In higher instar of 4^(t h) and 5^(th), over 89% host larva will die if they have been fed to compara tive higher dosage of 8.24×10~6 PIB/mL. The period from being infected to deat h of host larva is comparative short (about 3 to 5 days). The relationship betwe en accumulative disease death and time could be quite simulated by Weibull model .Statistic test showed that the predicted values well fit observed data,and t-t est indicated the parameters of all models reached significant level.