Insects Found – Still Monitoring

2009 – Issue 13

Bertha armyworm traps continue to be used for monitoring but so far numbers caught in Manitoba and Alberta indicate the risk is low. However, trap numbers in a few locations in Saskatchewan have surpassed the low threshold and fields in these areas may need to be watched more closely in the coming weeks. A risk map based on trap counts in Saskatchewan is available at the following link:http://www.agriculture.gov.sk.ca/Default.aspx?DN=e7788ad2-6b94-492a-95aa-3c7af80975aa. The map will be updated regularly as trap results come in.

Cabbage root maggots were again reported in Saskatchewan and Alberta.  A number of fields in Alberta had considerable damage. Drier conditions earlier this spring are generally not favorable for root maggots so it is a bit surprising to see significant damage. There are only cultural management tools for this insect pest. More information on cabbage maggot is available at:http://www.gov.mb.ca/agriculture/crops/insects/fad04s00.html. An audio discussion on root maggots and other insect pests with Dr. Lloyd Dosdall, University of Alberta is available at ACPC’s website http://www.canola.ab.ca/.

Lygus populations are being monitored in the Peace Region of Alberta where populations have exceeded economic thresholds in the Rolla and Spirit River areas. There is a range for the economic threshold depending on crop stage and price.  More information is available at the following link: http://www.gov.mb.ca/agriculture/crops/insects/fad12s00.html

Grasshopper activity increased with recent warm conditions and many areas report spraying of pastures and hayfields. Grasshoppers may become a concern in canola adjacent to a field cut for hay as the insects migrate to continue feeding. Continue scouting for grasshoppers because if caught early perimeter spraying may be all that is needed.  A specific economic threshold for grasshoppers in canola has not been established as it is not a preferred host crop, but it is currently considered to be in the range of 7 to 14 per m2, depending on the crop value and cost for control. More information on grasshoppers is available at the following link:http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex6463

 

Canola Watch