Tuesday, 12 June 2018

Predicted bertha armyworm development (Jun 14, 2018; Wk 06)

Bertha armyworm (Lepidoptera: Mamestra configurataBAW development continues to be 7-10 days ahead of normal development (Fig. 1).  

Figure 1.  Percentage of pupal stage heat requirements for emergence of bertha armyworm (as of June 20, 2018).

Near Saskatoon SK, adult emergence is well underway and oviposition is predicted to have begun this week. Based on climate data, oviposition near Saskatoon should begin around the third week of June.  

Reminder -Table 1. Projected dates for BAW adult emergence for June 4, 2018 (projected to June 30, 2018).

For those who are  now checking a bertha armyworm pheromone trap on a weekly basis, we provide an excellent photo kindly shared by Saskatchewan Agriculture to aid your identification and reporting of trap interceptions.  Note the kidney-bean white-patterned shape on each forewing but also know other cutworm species can resemble bertha armyworm moths so check carefully and thanks for your help!

Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of ManitobaSaskatchewanAlberta 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" - both English-enhanced or French-enhanced versions are available.