A slower start to the canola seeding season in 2022 could mean canola, when seeding does occur, will be starting off in warm moist soil. This could mean rapid emergence and good protection from seed treatments throughout the high-risk period, which ends around the four-leaf stage.
However, given the 2021 flea beetle experience, the pest will still be top of mind. That is what motivated Canola Council of Canada (CCC) agronomy specialists to write A Better Flea Beetle Management Plan in September 2021.
The CCC also launched a flea beetle management campaign this month. It included the following tips to improve spray results:
Use pesticides registered for flea beetles in canola. Refer to product labels for proper use instructions.
Consider the weather. Insecticide will be effective on cooler days as long as the flea beetles are active. Malathion is the only product that requires a minimum temperature of 18-20°C. Other product labels say to apply when flea beetles are active, but to avoid the warmest parts of the day. Some pyrethroid labels (Decis, for example) say they should not be applied when temperatures are above 25°C. However, if conditions are cool AND wet, don’t bother spraying anything. Flea beetles don’t like rain, and will take cover in the soil and leaf litter. Product labels also say not to spray if rain is likely within one hour.
Use nozzles that provide good coverage. Low-drift nozzles are well-suited for weed control but not flea beetle control. A dedicated sprayer pass with nozzles that produce smaller droplets will provide the coverage needed for improved flea beetle results.
For more on flea beetle lifecycles and management, please see the flea beetles chapter at CanolaEncyclopedia.ca. This article is based on two more detailed Canola Watch Fundamentals articles called How to assess leaf area loss from flea beetles and The flea beetle spray decision: 8 steps. Find them at canolawatch.org/fundamentals. While there, please sign up to receive our timely Canola Watch agronomy emails.