to the top of the page

  Home  »  News »  

Canola Flea Beetles Emerging

Posted: May 18 2023

Spring temperatures have warmed up above 600 F causing the flea beetles to emerge from overwintering areas and search for volunteer canola and other Brassicaceae weeds (wild mustard) to feed on. Crucifer and striped flea beetles have been observed in the northeast (Anitha Chirumamilla, LREC), Benson County (Scott Knoke) and northwest Minnesota (Dave Grafstrom). Both the striped flea beetle and the crucifer flea beetle have been observed with the crucifer flea beetle being more common. Flea beetles are easy to identify in the field by their flea-like hopping behavior. The crucifer flea beetle adult is a small, oval-shaped, dark beetle with an iridescent blue sheen on the black wing covers, measuring about ? inch long. The striped flea beetle adult is similar to the crucifer flea beetle in size and has two yellow stripes on its black wing covers.

As canola is planted, farmers and crop consultants need to plan to scout for flea beetles as soon as the crop emerges, at least 2-3 times a week. Insecticide seed treatments need to be confirmed they are working and providing good protection against flea beetle damage during the first 3 weeks after canola emergence. Feeding damage is often worst with hot temperatures, low moisture and low plant stands. Continue to scout until canola is in the 6-8 leaf stage when the crop can tolerate most flea beetle feeding pressure.

Flea beetle feeding on volunteer canola (on left) and yellow sticky traps used to monitor adult beetles (Anitha Chirumamilla, LREC) (P. Beauzay) North Dakota State University CROP & PEST REPORT May 18, 2023 2 If more than 25% defoliation is observed in canola fields, a foliar insecticide spray is warranted to prevent yield loss. Pyrethroids (3A) are the only class of insecticide registered for foliar control of flea beetles in canola (active ingredients - bifenthrin, deltamethrin, lambda-cyhalothrin, zeta-cypermethrin). One premix is labeled as Besiege (chlorantraniliprole + lambda-cyhalothrin). For insecticides registered for control of flea beetles for canola, please refer to the 2023 North Dakota Field Crop Insect Management Guide.
Our Fargo 2022 insecticide seed treatment trials against flea beetles examined thiamethoxam (Helix) at 23 fl oz / cwt alone and in combination with cyantraniliprole (Lumiderm, Fortenza), and clothianidin (Prosper) at 21.5 fl oz / cwt alone, in combination with cyantraniliprole (Lumiderm, Fortenza), and in combination with flupyradifurone (Buteo Start) (see Table 1). Flea beetle populations were about 75% striped flea beetle and 25% crucifer flea beetle. For feeding injury ratings, we observed slightly higher feeding injury when thiamethoxam and clothianidin were used alone compared to those same actives in combination with either cyantraniliprole or flupyradifurone. Yield also was significantly higher for the combination of two active ingredients (average of 2421 lbs/acre), compared to the single active ingredient (average of 2123 lbs/acre) and the untreated check (1831 lbs/acre).

Janet J. Knodel Extension Entomologist

Copyright 2023, Northern Canola Growers Association | Designed and developed by Odney