Department of Plant Protection, Urmia University, Urmia, Iran.
Department of Entomology, Kansas State University, Agricultural Research Center-Hays, Hays, KS.
J Econ Entomol. 2020 Aug 13;113(4):1648-1655. doi: 10.1093/jee/toaa066.
Cotton bollworm, Helicoverpa armigera Hubner, is a cosmopolitan polyphagous pest of many crops. Habrobracon hebetor Say and Helicoverpa armigera nucleopolyhedrovirus (HearNPV) are two important biocontrol agents used to manage this pest, sometimes in combination. We evaluated the sublethal effects of HearNPV on H. hebetor life table parameters under laboratory conditions when its host (second instar H. armigera) was treated with HearNPV, and tested H. hebetor females for their ability to discriminate against inoculated hosts. Emergence of adults reared as solitary larvae was reduced by half on LC30-inoculated larvae compared to controls, but not on LC5 or LC15-inoculated hosts. Low concentrations (LC5, LC15, and LC30) of HearNPV had no effects on overall parasitoid developmental time, but longevity and lifetime fecundity was reduced for females emerging from hosts receiving the LC30 treatment. Net reproductive rate (R0), intrinsic rate of increase (rm), and finite rate of increase (λ) were all decreased in a concentration-dependent manner in the LC15 and LC30 treatments, as were female life expectancy, age-specific survivorship (lx), and age-specific fecundity (mx), whereas population doubling time (DT) increased. Parasitoids did not discriminate against LC15-inoculated larvae in choice or no-choice tests, but parasitized more LC50-inoculated hosts than controls in the choice test, with no significant differences in total numbers of eggs laid in either case. Although parasitoids suffered some loss of fitness in HearNPV-inoculated hosts under these laboratory conditions, these agents still appear compatible for joint application against H. armigera under field conditions, provided parasitoid releases are made 2 d after NPV application.
棉铃虫，Helicoverpa armigera Hubner，是一种世界性的多食性害虫，危害许多作物。赤眼蜂 Habrobracon hebetor Say 和棉铃虫核型多角体病毒（HearNPV）是两种重要的生物防治剂，用于管理这种害虫，有时两者结合使用。我们评估了在实验室条件下，当宿主（二龄棉铃虫）被 HearNPV 处理时，HearNPV 对 H. hebetor 生命表参数的亚致死效应，并测试了 H. hebetor 雌性对接种宿主的辨别能力。与对照相比，在 LC30 接种幼虫上饲养的成虫的羽化率降低了一半，但在 LC5 或 LC15 接种的宿主上没有降低。 HearNPV 的低浓度（LC5、LC15 和 LC30）对整体寄生蜂发育时间没有影响，但从接受 LC30 处理的宿主中羽化的雌性寿命和终生产卵量减少。在 LC15 和 LC30 处理中，净生殖率（R0）、内禀增长率（rm）和有限增长率（λ）均呈浓度依赖性降低，LC15 和 LC30 处理中雌性预期寿命、特定年龄存活率（lx）和特定年龄产卵量（mx）也降低，而种群倍增时间（DT）增加。在选择或非选择试验中，寄生蜂没有对 LC15 接种的幼虫进行歧视，但在选择试验中，寄生蜂寄生的 LC50 接种宿主比对照多，在两种情况下产卵总数都没有显著差异。尽管在这些实验室条件下，寄生蜂在 HearNPV 接种的宿主中遭受了一些适应度的损失，但这些药剂在田间条件下仍可与 NPV 联合应用，前提是在 NPV 应用后 2 天释放寄生蜂。
