Numerous calls have been coming in this week on flea beetles feeding and damaged canola. If you have not yet, you should get out to your fields ASAP and see for yourself.
As you are looking at your plants, run through this checklist
- When did you seed the field, has it been longer than 3 weeks (prior to May 22)?
- What is your plant population, is it less than 7 plants/ft2 (make a ‘L’ with your feet, how many plants are in the ‘L’)?
- What stage is your canola at – is less than 3 leaves?
- What % of the leaf has been bitten/injured – does it look like more than 25%?
- Are the flea beetles still seen and feeding on plants?
If you have answered yes to all these question, you should consider an insecticide application to control the flea beetle population.
The seed treatment has an expected lifespan of 3 to 4 weeks, so once seed is in the ground the clock is on and as you get closer to the end of the 3rd week, the flea beetles are becoming less and less controlled. Flea beetle feeding stresses the canola and with cool growing conditions, the canola is not growing as quickly as it could.
Many fields are in the not so ideal situation of slow growing canola, seed treatment insecticide component efficacy diminishing and high populations of flea beetles still in fields. For more information see the June 12th Insect and Disease Update from MAFRI: Manitoba Insect and Disease Update – June 12