Scouting is an important component of management. If you don’t know what’s in your field, you can’t evaluate what control measures to use.
Yearly scouting is needed to assess what pests exist in fields, as populations don’t always remain constant. For example, in 2016 there were higher counts of cutworm but lower incidence of Bertha armyworm. Diamondback moth arrive via winds from our Southern neighbours, and thus are very unpredictable. Flea beetles are usually present but damage depends on the effect growing conditions have on their development as well as ability of the canola crop to outgrow feeding damage.
Identifying pests can also help prevent future problems. Recently, a team of researchers from Saskatchewan, Alberta and Ontario identified a species of midge that is slightly different from the Swede midge. The Swede midge has caused major issues for canola growers in Northern Ontario, however the economic impact to Prairie canola growers, as well as the insect biology, is still being assessed. The new midge species is different physically and in DNA makeup, according to the research scientists at Agriculture Canada. However, the economic impact of this new species is not yet known.
Establishing a canola crop with good, uniform plant counts goes a long way towards minimizing pest impact. Well-fertilized crops allow for more rapid and even development and maturity. Proper rotations can also help to reduce impact.
For more information on insect identification, the Canola Council of Canada website (canolacouncil.org) has excellent information on pests and scouting
Doug Fehr is with DuPont Crop Protection Canada.