Department of Biology, Carleton University, Ottawa, ON, Canada.
School of Environmental Sciences, University of Guelph, Guelph, ON, Canada.
J Econ Entomol. 2021 Apr 13;114(2):728-738. doi: 10.1093/jee/toaa323.
Swede midge (Contarinia nasturtii Kieffer) is an invasive, economic pest of canola (Brassica napus L.) that threatens production throughout Canada. Swede midge has up to four overlapping generations, placing canola at risk of multiple infestations in the field. The relationship between single and multiple swede midge infestations at different canola stages, and the resulting impacts on yield, are unknown. Laboratory experiments were conducted to evaluate the impact of single and multiple infestations of swede midge on four plant stages of canola: three-leaf, seven-leaf, primary bud, and secondary bud. Previously, the seven-leaf and primary bud stages were considered vulnerable to swede midge, but we determined that the secondary bud stage is also vulnerable. Evidence of compensation by canola in response to herbivory by swede midge was discovered. Compensation occurred mainly through increased production of tertiary racemes and pods and was maximized with exposure of 4.5-6.5 female midges per plant. Although compensation may increase potential yield, it also results in uneven crop maturation resulting in delayed harvest and yield loss. Consequently, to prevent delays in maturation and harvest, insecticides should be applied before these densities are reached.
斯氏潜蝇（Contarinia nasturtii Kieffer）是一种入侵性的、经济上重要的油菜（Brassica napus L.）害虫，它威胁着加拿大各地的油菜生产。斯氏潜蝇有多达四个重叠的世代，这使得油菜在田间面临多次虫害的风险。单次和多次斯氏潜蝇在不同油菜阶段的侵染，以及对产量的影响尚不清楚。进行了实验室实验，以评估单次和多次斯氏潜蝇侵染对油菜四个生长阶段的影响：三叶期、七叶期、主芽期和次芽期。此前，七叶期和主芽期被认为容易受到斯氏潜蝇的侵害，但我们发现次芽期也很容易受到侵害。油菜对斯氏潜蝇取食的补偿作用的证据被发现了。补偿主要通过增加三级序和荚果的产量来实现，通过每株暴露 4.5-6.5 只雌性潜蝇来达到最大化。尽管补偿可能会增加潜在产量，但也会导致作物成熟不均匀，导致收获延迟和产量损失。因此，为了防止成熟和收获延迟，应该在达到这些密度之前使用杀虫剂。
