Journal of Economic Entomology (2021) 114, 728-738

Matthew J. Muzzatti, Boyd A. Mori and Rebecca H. Hallett (2021)
Compensatory abilities of canola in response to Swede midge (Diptera: Cecidomyiidae) damage
Journal of Economic Entomology 114 (2), 728-738
Abstract: 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.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Rebecca H. Hallett

Research topic(s) for pests/diseases/weeds:
resistance/tolerance/defence of host

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Contarinia nasturtii	Rape/canola (Brassica napus)