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My 1st 1st-author paper was published yesterday in the Journal of Economic Entomology! The 1st piece from my MSc at @uofg with @RHHallett and @BoydMori at @UAlberta
Compensatory abilities of canola in response to swede midge damage
https://doi.org/10.1093/jee/toaa323
Here's a thread:
Compensatory abilities of canola in response to swede midge damage
https://doi.org/10.1093/jee/toaa323
Here's a thread:
Swede midge is a major pest of canola in Canada, and is really difficult to control bc of its complex life history - concealed larval feeding, overlapping gen's throughout the growing season, and a portion from each gen enters into diapause.
Additionally, canola is known to compensate in response to herbivory - it can produce new secondary and tertiary racemes (new branches that can still produce seed)
To develop an IPM program for swede midge in canola, it is crucial to understand the magnitude of compensatory responses of canola at different plant stages
Williams and Hallett previously infested single canola plants at the primary bud stage with densities of 0, 5, 10, 50, and 100
midge.
They found that a density of ~0.6-2.4 midge/plant = 10% reduction in pods + seed weight. https://link.springer.com/article/10.1007%2Fs10340-017-0940-2
midge.They found that a density of ~0.6-2.4
midge/plant = 10% reduction in pods + seed weight. https://link.springer.com/article/10.1007%2Fs10340-017-0940-2
Given their large range of densities, and the small # of midge needed to reduce pods and seed weight, a subsequent investigation of a smaller range of swede midge densities at different plant stages was required.
midge needed to reduce pods and seed weight, a subsequent investigation of a smaller range of swede midge densities at different plant stages was required.
We ran 2 experiments:
Exp 1 - we tested single infestations of 0, 2, 5, and 10 midge on 3-leaf, 7-leaf, primary (1°) bud, and secondary (2°) bud stage canola
(picture below of growth stages)
Exp 1 - we tested single infestations of 0, 2, 5, and 10
midge on 3-leaf, 7-leaf, primary (1°) bud, and secondary (2°) bud stage canola (picture below of growth stages)
Exp 2 - we tested multiple infestations of swede midge at the same growth stages. Midge were introduced at the:
seven-leaf
seven-leaf + 1° bud
seven-leaf + 2° bud
seven-leaf + 1° bud + 2° bud
seven-leaf
seven-leaf + 1° bud
seven-leaf + 2° bud
seven-leaf + 1° bud + 2° bud
For both experiments, all pods and racemes were harvested and counted, and seeds were weighed separately for each raceme category (primary, secondary, tertiary)
Plant damage was also measured in Exp 2
Plant damage was also measured in Exp 2
We used ANOVA to determine diff's among growth and yield parameters, and we ran regressions analyses to determine the relationship between canola growth and yield at low swede midge densities
Bc we measured SO MUCH data, I'll keep it concise for this thread:
Our data provided evidence of compensation by canola - mainly through increased production of tertiary racemes and pods at 1° and 2° bud stages.
This effect was max'd with exposure of 4.5-6.5 midge/plant
Our data provided evidence of compensation by canola - mainly through increased production of tertiary racemes and pods at 1° and 2° bud stages.
This effect was max'd with exposure of 4.5-6.5
midge/plant
While it could be said that compensatory effects could help reduce yield loss, this is unlikely given that compensation in canola results in uneven and delayed maturation, which can disrupt harvesting timing.
Additional racemes may not even contribute to final yield
Additional racemes may not even contribute to final yield
In Exp 2, all treatments that had additional infestations of midge (regardless of plant stage) had higher dmg compared to a single infestation, but decreased 3 d earlier.
This suggests canola allocates more resources to developing MORE racemes, which could delay maturity
This suggests canola allocates more resources to developing MORE racemes, which could delay maturity
From our results, we suggest that insecticides targeting swede midge in canola be applied before densities at which canola can optimally compensate (4.5-6.5 midge/plant) are reached.
midge/plant) are reached.
Tons of people to thank for this enormous effort - Dr. Art Schaafsma at the @RidgetownCampus, @originalGradish, and Dr. Michelle Edwards.
This work would also not have been possible without the multi-year teams of amazing undergraduate students.
Agricultural lab and field work can be grueling (but rewarding) stuff, with lots of hot field days and weeks spent collecting data. So thank you!
Agricultural lab and field work can be grueling (but rewarding) stuff, with lots of hot field days and weeks spent collecting data. So thank you!
