甜菜夜蛾核型多角体病毒对宿主种群的控制作用

The control effect of Spodoptera exgiua nuclear polyhedrosis virus on its host population

室内试验表明,甜菜夜蛾核型多角体病毒对宿主种群有明显的控制作用。当饲毒浓度在1.14×10~8PIBs/mL 以上时,能引起97％的甜菜夜蛾幼虫死亡;饲毒后1～8天内,致死中浓度 LC_(50)值在8.4718×10~5～2.6098×10^(12)PIBs/mL 之间;在饲毒浓度范围内,致死中时间 LT_(50)在1.98～6.99天之间;感病幼虫每日病死时间分布可用时间-剂量-条件死亡率模型较好地拟合,累计病死时间分布可用 Gompertz 模型拟合。室内试验还表明,病毒对甜菜夜蛾种群有明显的亚致死作用。免于病死蛹重量减轻,羽化所得雌成虫产卵量下降,产卵期延长;从感病高龄幼虫发育的成虫能将病毒传播至子代,引起20%～48%的子代幼虫死亡,并使子代成虫产卵量下降。田间试验表明,病毒除具有明显的控制作用外,还有一定的后效作用。

The results of laboratory test indicated that the control effect of Spodoptera exiguanuclear polyhedrosis virus(SeNPV)on the beet armyworm,S.exigua(Lepidoptera:Noctu-idae)was significant.Viral infection resulted in 97% larval mortality after the 3rd instar larvaewas infected by SeNPV at the concentration of 1.14×10~8 PIBs/mL or more.The LC_(50) valueswere 8.4718×10~5-2.6098×10^(12)PIBs/mL from the 1st to 8th day after treatment,and theLT_(50)values were decreased from 6.9856 days at the concentration of 1.14×10~6 to 1.9817daysat the concentration of 1.14×10~9 PIBs/mL.The daily distribution of mortality could be wellsimulated with Time-Dose-Mortality model,and the daily distribution of the accumulated mor-tality of larvae was well fitted by Gompertz model.The results also showed that the SeNPV in-fection displayed a sublethal effect by decreasing the survival pupal weight,extending oviposi-tion duration of adults,and decreasing the fecundity of adults;the adults developing from virus-infected larvae transmitted the virus to their progeny,causing 20%-48% mortality of nextgeneration neonates,and decreasing the fecundity of progeny adults.The results of field trialsshowed that this virus had also certain residual effects besides killing the S.exigua larvae.