Canola Insect Trapping 2025 | Northern Canola Growers Association

Pheromone traps for bertha armyworm and diamondback moth were monitored by IPM scouts, insect trappers and Extension agents/Specialists through the IPM Crop Survey Program at 16 trap sites in 15 counties of North Dakota and at two trap sites in one county in Minnesota. The season final trap counts for bertha armyworm indicated a low infestation risk (<300 total cumulative moths per trap per season) at all trap sites in North Dakota and Minnesota. The cumulative number of bertha armyworms captured increased 6-fold to 1,584 moths (average of 88 adults per trap) in 2025, compared to 256 moths (average of 18 adults per trap) in 2024. The highest trap catches were observed at Walsh (239 moths), Towner (214 moths), Rolette (196 moths) and Mountrail (181 moths) counties. In Roseau County, Minnesota, bertha armyworm declined to 26 and 55 moths per season.

The cumulative number of diamondback moths captured increased 6-fold to 19,190 moths (average of 1,066 adults per trap) in 2025, compared to 1,345 (average of 96 moths per trap) in 2024. The highest trap catches (>1,500 cumulative moths per trap per season) were observed at Cass (2,567 moths), Ward (2,449 moths), Towner (2,159 moths) and Ramsey (1,639 moths) counties. In Roseau County, Minnesota, diamondback moth ranged from 62 to 666 cumulative moths per trap per season.

Bertha armyworm and diamondback moth are occasional insect pests of canola in North Dakota and northwestern Minnesota. Routine monitoring using pheromone traps in canola fields can help predict when scouting is necessary and when populations are economically significant to canola yield using thresholds based on larval densities in fields. Thanks to the Northern Canola Growers Association, the USDA NIFA CPPM EIP grant (#2021-70006-35330) and the North Dakota Department of Agriculture CAPS Program for support.

Story courtesy of: North Dakota State University Crop & Pest Report No. 19 - chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://www.ndsu.edu/agriculture/sites/default/files/2025-09/19%20September%2025%202025%20Final.pdf