Predicted bertha armyworm development (June 6, 2019; Wk 09)

Bertha armyworm (Lepidoptera: Mamestra configurata) - Based on BAW model runs, pupal development is nearing 80% in some areas of southern and central AB and SK (Fig. 1). BAW adults may begin to emerge within the next 10 days (Table 1). It is advisable to place pheromone traps in fields when pupal development is 80% to capture the full extent of adult flight activity. Based on this value, traps should be put out in SK and AB fields this week.

Figure 1. Predicted bertha armyworm (Mamestra configurata) pupal development acrossthe Canadian prairies as of June 3, 2019. 

Table 1. Predicted emergence date of bertha armyworm moths at 

select locations across the Canadian prairies in 2019.

Recent warm conditions have advanced bertha armyworm (BAW) pupal development. Compared to last week, development is 2-6 days faster and development is 2 days ahead of normal (based on climate normals).  Model outputs were run for bertha armyworm for Saskatoon SK (Fig. 2), Lethbridge AB (Fig. 3), and Edmonton AB (Fig. 4).

Figure 2. Predicted development of bertha armyworm populations near Saskatoon SK as of June 3, 2019. 

Figure 3. Predicted development of bertha armyworm populations near Lethbridge AB as of June 3, 2019. 

Figure 4. Predicted development of bertha armyworm populations near Edmonton AB as of June 3, 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.