2015 Pea Leaf Weevil Forecast

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The annual pea leaf weevil (Sitona lineatus L.) survey was carried out in late May and early June, 2014. Damage in 2014 was much higher than in 2013, especially in southern Alberta. The 2014 survey was based on damage ratings in 124 fields from 31 municipalities. In each field the total notches per plant are counted on 50 plants (10 plants in 5 locations near the field margin). The damage rating for a particular field is the average number of notches per plant. For information about the pea leaf weevil and its life cycle.

For any producers south of Highway 1 plus the counties of Kneehill, Wheatland, Newell and Cypress there is risk of damaging levels of pea leaf weevil in 2015. The areas in northern Wheatland county and Kneehill county have not previously seen such high populations of pea leaf weevil. Producers should use this information along with their own experience to plan control strategies such as seed treatment for the 2015 crop year. Research has shown that seed treatment is much more effective in reducing losses from pea leaf weevil than foliar treatments.

In addition areas even further north have seen significant pea leaf weevil damage on fababeans. This insect causes as much or more damage on fababeans. The true economic damage of this insect on both peas and fababeans on the higher organic matter soils of central Alberta is not well understood.

Some VERY low levels of feeding damage were once again found in throughout central Alberta. This damage is so low that there is no risk of serious issues with pea leaf weevil throughout central Alberta in 2015. This area is almost exactly the same as previous years and although this is a range expansion the damage rating numbers are still exceedingly low. It will be important to watch the development of these populations over the next few years. Survey locations shown with black circles had no evidence of pea leaf weevil feeding on any of the plants assessed.

Although this is not a strict forecast, experience has shown us that the higher the damage rating in this survey, the higher the risk of damage in the next year. Based on studies of pea leaf weevil biology, moisture in August appears to be a significant predictor of changes in population. Together this information suggests that pea leaf weevil has the potential to be an important pest in 2015.

Spring weather conditions have a very large impact on the timing and severity of pea leaf weevil damage. When warm conditions (>20o C) persist for more than a few days in late April or early May the weevils arrive in fields early. Early arrival corresponds to the potential for higher yield losses. In years where cool weather persists, the arrival of PLW can be much later and the resulting yield impact appears to be lower especially when the crop advances past the 6 node stage before weevils arrive. In every case control decisions should be made on a field by field basis.

Life cycle information

Frequently Asked Questions

The 2014 pea leaf weevil survey was carried out by Alberta Agriculture and Rural Development. Thank you for your contribution.

Thank you David Giffen, Agriculture and Agri-Food Canada, Saskatoon for building the map.

For more information on this insect and its management contact the Ag-Info Centre at 310-FARM (3276).


Other Documents in the Series

  2016 Pea Leaf Weevil Forecast
2015 Pea Leaf Weevil Forecast - Current Document
For more information about the content of this document, contact Scott Meers.
This document is maintained by Shelley Barkley.
This information published to the web on January 20, 2015.
Last Reviewed/Revised on January 21, 2015.