2011 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, 2010. Pea leaf weevil (PLW) damage of concern was found in essentially the same range as the previous two years. Damage increased in severity in Wheatland county but otherwise the damage is similar and in similar areas to previous years. The 2010 survey was based on damage ratings in 97 fields from 24 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.
Click for a larger map
PLW damage was more common in the northern areas of its established range than in 2009 but still below 2007 levels. Some VERY low levels of feeding damage were found in Red Deer, Stettler, Paintearth and Provost counties as well as Special Areas 4. This damage is so low that there is no risk of serious damage in 2011 but it does show that the weevils may have expanded their range. 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.

For any producers south of Highway 1 plus the counties of Wheatland, Newell and Cypress there is risk of damaging levels of pea leaf weevil in 2011. Producers should use this information along with their own experience to plan control strategies for the 2011 crop year.

Although this is not a strict forecast, experience from the last couple of years 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 2011.

Spring weather conditions have a large impact on the timing and severity of pea leaf weevil damage. When warm conditions (>20 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

Follow this link for a page size printable version of the forecast map.

Follow this link to the Agriculture Canada tri-provincial forecast maps. Please go to the drop-down menu to locate the pea leaf weevil map.

Follow this link to view the 2011 insect forecast video presentation.
 
 
 
 
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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 December 7, 2010.
Last Reviewed/Revised on December 14, 2012.