As you are walking through flowering/podding canola you may notice some plants looking like the photo to the right. These unopened flower galls are due to a newly discovered pest to canola – canola flower midge.
What Is Canola Flower Midge?
Closely resembling and originally thought to be swede midge, the canola flower midge was officially identified on the Prairies in 2017.
Adult females lay their eggs on developing flower buds and larvae then hatch and develop here. This is what causes damage to the plant. Larvae inside a damaged flower can be seen in the second picture. Once mature, larvae leave the galled flowers, fall to the ground, and create cocoons. Cocoons will either overwinter or pupate in the same season. At least two generations of canola flower midge can happen in the same year if conditions are conducive.
Signs in the Field
The only symptoms linked to canola flower midge so far are bottled or galled flowers. Larvae feeding results in swelling and prevents the flower from opening, which is seen as the tell-tale “bottle-shaped” gall formations. These flowers will not produce pods or set seed.
The canola flower midge is found throughout the Prairies. However, field surveys indicate that damage is found in higher concentrations in the Dark Brown and Black soil zones.
Impact on Yield
Research so far has shown that this new insect does not cause serious damage to canola. Infestations have remained low and have not caused economic injury. The highest amount of injury occurs 1-2 weeks after flowering begins.
Summary
At this moment, nothing can be or is worth being done to stop canola flower midge damage on your crop. Infestations are quite minimal and economic losses are yet to be seen. You may just notice the odd plant with these bottle-shaped flowers attached.
Jill Sparrow
Precision Agronomist
CropPro Consulting