Thursday, 25 June 2020

Bertha armyworm monitoring

Bertha armyworm (Lepidoptera: Mamestra configurataModel simulations as of June 21, 2020, indicate that 69 % of the population is in the pupal stage (Fig. 1), 26% in the adult stage (Fig. 2) and 5 % is predicted to be in the egg stage (Fig. 3).  Across the Parkland and Peace River regions, BAW populations are predicted to be predominantly in the pupal stage (Fig. 1).  Last week BAW adults were predicted to occur in isolated areas across the southern prairies (Fig. 2).  This week adults should be collected in BAW traps across south and central regions of the prairies.  Eggs may be occurring in southern regions (Fig. 3).  
Figure 1. Predicted percent of bertha armyworm (Mamestra configurata) population at pupal stage as of June 21, 2020

Figure 2. Predicted percent of bertha armyworm (Mamestra configurata) population at adult stage as of June 21, 2020

Figure 3. Predicted percent of bertha armyworm (Mamestra configurata) population at egg stage as of June 21, 2020

The BAW model was run until June 30, 2020 to project developmental status. The simulations for Saskatoon (Fig. 4) and Brandon (Fig. 5) indicate that first occurrence of BAW larvae may begin later next week

Figure 4. Projected bertha armyworm (Mamestra configurata) phenology at Saskatoon SK as of June 30, 2020.

Figure 5. Projected bertha armyworm (Mamestra configurata) phenology at Brandon MB as of June 30, 2020.

Weekly Pheromone-baited Trapping Results - Early season detection of bertha armyworm is improved through the use of pheromone-baited unitraps traps deployed in fields across the Canadian prairies.  Click each province to access moth reporting numbers observed in Alberta, Saskatchewan and Manitoba as they become available. Check these sites to assess cumulative counts and relative risk in your geographic region.

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 "Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide" which is a free downloadable document as both an English-enhanced or French-enhanced version.

Refer to the PPMN Bertha armyworm monitoring protocol for help when performing in-field scouting.  Use the images below (Fig. 6) to help identify egg masses and the economically important larvae in canola.  Review the 2019 Insect of the Week which featured bertha armyworm and its doppelganger, the clover cutworm!

Figure 6. Stages of bertha armyworm from egg (A), larva (B), pupa (C) to adult (D).
Photos: J. Williams (Agriculture and Agri-Food Canada)