Localized areas of Alberta are experiencing Bertha armyworm outbreaks. The extent of the outbreaks is still being determined. Daily scouting in high-risk fields is important. Bertha armyworm larvae move between fields, so density can change day to day. At high densities, economic crop damage can occur rapidly.
Bertha armyworm outbreaks can be very localized, and not all fields will be impacted. Fields at higher risk include fields with dense patches of kochia or lamb’s quarters and fields located in areas that had medium or high pheromone trap capture. Infestations are still possible in fields with low trap capture areas.
While primarily a pest of canola, Bertha armyworms can also cause economic damage to
- Mustard
- Flax
- Quinoa
- Hemp
- Peas
- Alfalfa
- Potatoes
All of the crops listed above should also be monitored.
Over 15,000 acres of canola and peas have been sprayed for Bertha armyworm in Vulcan County. Densities of larvae above 50 per square metre were observed in some fields. Reports of fields above threshold have come in from Special Areas 4 and the Municipality of Taber.
Learn more about Bertha armyworms at
https://www.canolacouncil.org/canola-encyclopedia/insects/bertha-armyworm/
Questions? Contact Teagan Scott, County Ag Fieldman.
