Map of the Week – Bertha armyworm

June 13, 2018 – Issue 11

Growing degree days across most of the Prairies have reached the threshold for adult bertha armyworm (moth) emergence from overwintering pupae. That is 7-10 days ahead of normal. Egg laying begins shortly after adult emergence and young worms emerge about a week after that. See the Prairie Pest Monitoring Network (PPMN) report for this week.

Will it be a bad year for bertha armyworm? “Early” doesn’t necessarily mean “bad”. The risk map for BAW (based on 2017 pheromone trap interceptions) suggests that BAW will be limited to only a few areas of the Prairies this year.‎ Numbers could still be high in those areas but PPMN anticipates fewer acres will be affected compared to other outbreak years. Pay attention to trap counts and know that localized hot spots can flare up. Trap counts, when posting starts for 2018, will be here:

Alberta trap counts
Saskatchewan trap counts
Manitoba trap counts

Further reading:

Canola Encyclopedia chapter on bertha armyworm
PPMN bertha armyworm articles
PPMN lygus prediction model for 2018

Canola Watch