Overwintered canola and ground beetles

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Some Alberta producers may be seeing large numbers of beetles while combining canola fields this spring.

Researchers would like to connect with farmers who are finding large numbers of ground beetles while combining their overwintered canola fields. One such report has been received from a location north of Edmonton, and more are likely. The beetles are black and 6 to 9 mm in length.

Kevin Floate is a research scientist with Agriculture and Agri-Food Canada in Lethbridge, and he says that this outbreak is similar to some outbreaks reported in 2010.

In that year, unusually large numbers of ground beetles were reported on a farm near Pickardville. Unusually high populations of these beetles were also reported across a large area that included sites near Camrose, Falher, High Prairie, Vegreville and Wetaskiwin.

Researchers concluded that unusually cool summer temperatures along with the late harvest in 2009 – also delayed by snow – likely left an abundance of canola seed on the soil. That abundant food supply allowed a larger than normal number of adults to survive and emerge in the spring of 2010. Those beetles then moved into surrounding fields in search of food. They found that the beetles’ numbers returned to normal levels in 2011.

“Given the large numbers of unharvested acres of canola last fall,” he says, “I thought conditions might be ripe for such outbreaks this spring.”

Floate emphasises that these beetles are not pest insects. They are beneficials, and farmers should not spray them. Adults feed on the seeds of weeds and other plants lying on the ground, and their larvae eat other insects including pest species. Eggs laid in the soil over the next few weeks will produce more adults later this summer and possibly more reports of outbreaks.

Besides the contact information of farmers finding these beetles, Floate is looking for:

  • a few dozen beetles per location to determine species composition
  • cropping history of the field going back at least 2 years
  • scope of the outbreak – affected acres
  • quantification of beetles numbers, such as high-resolution photos or a guestimate of the number in a square metre

Email kevin.floate@canada.ca for more information.

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