FP Insects

Pea Leaf Weevil – A New Potential Pest in Manitoba

Pea leaf weevil is a serious pest of field peas and faba beans in Saskatchewan and Alberta. It has not yet been reported in Manitoba, but it is moving eastward. In 2017, weevil damage was identified in north-west and north-central North Dakota and along the Manitoba-Saskatchewan border (see map). Vigilant scouting in the western part of our province is necessary to identify and manage the pest.

Adult pea leaf weevil showing alternating light and dark brown stripes extending from the thorax to the abdomen Photo: H. Goulet, AAFC-Ottawa.

In spring, adults fly in from overwintering sites (perennial legume crops) and lay eggs close to host plants (field peas and faba beans). Larvae cause economic damage by feeding on root nodules, resulting in poor plant growth. Adult weevils feed on leaves, but rarely cause economic damage. The characteristic leaf notching on leaf margins can be used to monitor pest presence (Figure 1). The best time to look for potential feeding damage is at the end of May to early June.

For pea leaf weevil density estimates throughout Saskatchewan and Alberta in 2018, along with pea leaf weevil ID and scouting information, see the Prairie Pest Monitoring Network’s Pea Leaf Weevil blog post.

For more information regarding pea leaf weevil scouting methods, thresholds and management, see NDSU’s Integrated Pest Management of Pea Leaf Weevil factsheet.

For a video explaining the action thresholds of pea leaf weevil and how to scout for feeding damage, view Pulse School: Scouting the Elusive Pea Leaf Weevil.