甜菜夜蛾核型多角体病毒对宿主种群的控制作用

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1.14×108PIBs/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LC50值在8.4718×105～2.6098×10 12PIBs/mL之间;在饲毒浓度范围内,致死中时间LT50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 control effect of Spodoptera exgiua nuclear polyhedrosis virus on its host population

The results of laboratory test indicated that the control effect of Spodoptera exigua nuclear polyhedrosis virus(SeNPV)on the beet armyworm,S.exigua(Lepidoptera:Noctuidae)was significant.Viral infection resulted in 97% larval mortality after the 3rd instar larvaewas infected by SeNPV at the concentration of 1.14×10⁸ PIBs/mL or more.The LC₅₀ valueswere 8.4718×10⁵-2.6098×10¹²PIBs/mL from the 1st to 8th day after treatment,and the LT₅₀ values were decreased from 6.9856 days at the concentration of 1.14×10⁶ to 1.9817daysat the concentration of 1.14×10⁹ PIBs/mL.The daily distribution of mortality could be wellsimulated with Time-Dose-Mortality model,and the daily distribution of the accumulated mortality of larvae was well fitted by Gompertz model.The results also showed that the SeNPV infection displayed a sublethal effect by decreasing the survival pupal weight,extending oviposition 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.