Bertha armyworm monitoring (July 5, 2019; Wk 13)

Bertha armyworm (Lepidoptera: Mamestra configurata) - Last week (Fig. 1), bertha armyworm adults were emerging across the prairies and oviposition began across most of the southern prairie regions of SK, AB and MB.  That means it's time to start check the undersides of canola leaves for egg masses and newly hatched larvae!

Figure 1.  Predicted precent of bertha armyworm (Mamestra configurata)  populations at EGG STAGE across the Canadian prairies as of June 24 2019. 

Here's where bertha armyworm moths were intercepted last year (Fig. 2) so areas previously highlighted in yellow, gold, orange or red should be on the lookout in 2019 for larvae.  Also watch your provincial monitoring networks who are weekly recording cumulative pheromone-baited traps in Alberta, Saskatchewan (table on Left of webpage), and Manitoba (pg 7).

Figure 2.  Cumulative moth counts from pheromone-baited unitraps deployed during the 2018 growing season.

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 "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.

Again, thanks to John Gavloski (Manitoba Agriculture) who helped update the PPMN Bertha armyworm monitoring protocol.  Use the images below (Fig. 3) to help identify moths from the by-catch that will be retained in phermone-baited unitraps.


Figure 3. Stages of bertha armyworm from egg (A), larva (B), pupa (C) to adult (D).
Photos: J. Williams (Agriculture and Agri-Food Canada)

Also be sure to review the Insect of the Week which features bertha armyworm and its doppelganger, the clover cutworm!