|The pea leaf weevil (Sitona lineatus L.) decreased in severity of damage and the range it is found in has not expanded in 2008. The 2008 survey was based on damage ratings in 88 fields (22 municipalities) carried out in late May. For information about the pea leaf weevil life cycle.|
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The survey is done based on leaf notch counts on 50 plants per survey field. The damage rating for a particular field is the average number of notches per plant. The pea leaf weevil has not expanded its range beyond were it was found in 2007 (southern Alberta and the southern portion of central Alberta). The survey was expanded north to include Red Deer, Lacombe, Settler, Paintearth and Provost counties. The weevil and its damage was NOT noted in any of the new counties included in the survey area. In areas where the Pea Leaf Weevil is established the numbers of weevils present and the damage they caused was much lower than experienced in 2007. This insect was found in Saskatchewan for the first time in 2007. Its presence has been confirmed as far east as Maple Creek, SK.
Although this is not a strict forecast, experience from the last couple of years has shown us that areas with greater than 9 notches per plant (dark tan on the map) have had high levels of damage in the next year. If this trend follows through into 2008 then we can expect high levels of pea leaf weevil damage including parts of the counties of Vulcan, Lethbridge, Taber, Warner and Cypress. Producers in areas with greater than 9 notches per plant should include control options in their pea crop budget for next year. The control options at this point include Matador as a foliar application and Cruiser as a seed treatment. Based on biology literature on this species, moisture in August appears to be a significant predictor of changes in population. This information suggests that pea leaf weevil should be a more significant pest in 2009 as compared with 2008.
2008 forecast based on 2007 survey data
Life cycle information
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