Swede Midge Needs Your Attention!

Swede midge larvae and damage on canola plant
Swede midge larvae and damage on canola

The Ontario Canola Growers, OMAF and MRA and the University of Guelph are working together to monitor swede midge this season.

As swede midge is difficult to detect until the damage has been done, monitoring stations have been set up in Ontario’s major canola growing areas.

You will find the 2013 trap count maps indicating adult swede midge populations at www.ontariocanolagrowers.ca.  Also on the website are valuable ID and management guides to help you gain a better understanding of swede midge.

It is important to regularly check this website for updates on the level of swede midge in your growing area until your canola is beyond the vulnerable stage.

If swede midge populations are at the 25+ level (orange or red on map) during the canola’s most vulnerable growth stages (before flowering) a treatment spray is likely warranted, but at other times of growth higher numbers may be tolerated.

In some areas (in particular the Shelburne/Dufferin area) swede midge populations were very high early in the season, but have fallen off after treatment for flea beetle. However, this will be a temporary protection. We have received reports of swede midge populations rebounding and are beginning to see plant damage in some areas.

The two approved products for treatment of swede midge in canola are Matador and Coragen.

Coragen appears to offer a somewhat extended residual effect (1 to 2 weeks). Coragen is not systemic, but it will move through the leaf to protect both leaf surfaces. Coverage is the most important issue especially at the growing point where the midge lay their eggs and larvae develop. Spraying larger plants means that more surface area needs to be protected, including new buds that develop in leaf axis. Therefore, at more advanced crop stages, higher water volume may be necessary to achieve good coverage

Once flowering on secondary/tertiary branches is initiated there is no further risk of swede midge damage.

Please remember when applying an insecticide to wear appropriate protective wear and follow bee safety guidelines.