Predicted bertha armyworm development (May 30, 2019; Wk 08)

Bertha armyworm (Lepidoptera: Mamestra configurata) - Pupal development is approximately 40%. Average development is 48% (Fig. 1). 

Figure 1. Predicted bertha armyworm (Mamestra configurata) pupal development acrossthe Canadian prairies as of May 28, 2019. 

In order to determine when adults may emerge, the BAW model was run for Brandon MB (Fig. 2), Saskatoon SK (Fig. 3), Lethbridge AB (Fig. 4) and Edmonton AB (Fig. 5) and projected to June 30, 2019. Model projections indicate that adults will begin to emerge in mid June. Recent heat will advance development of pupae. Traps should be placed in fields when pupal development reaches 80%. Based on model projections, it is advisable that traps be placed in fields on or before June 7. 

Figure 2. Predicted development of bertha armyworm populations near Brandon MB projected to June 30, 2019.  

Figure 3. Predicted development of bertha armyworm populations near Saskatoon SK projected to June 30, 2019.   

Figure 4. Predicted development of bertha armyworm populations near Lethbridge AB projected to June 30, 2019.  

Figure 5. Predicted development of bertha armyworm populations near Edmonton AB projected to June 30, 2019.   

Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of Manitoba, Saskatchewan, Alberta and the Prairie Pest Monitoring Network. Also refer to the bertha armyworm pages within the new "Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide" as an English-enhanced or French-enhanced version.