While most of us would like to be at the lake this summer, many insect pests would prefer to stay at home in your canola crop. In most years the insect numbers are low enough that the spraying of insecticides in not necessary, but you still should keep an eye on them as their populations can increase rapidly. One way to tell what is living in and under the canopy of your crop is by using a sweep net. This is a 38cm diameter net that you sweep through the crop in a 180 degree sweep 10 times. Take a couple of steps between the sweeps. Do this three or four times in different areas of the field.
You will be surprised at what you will have in your net. Count and sort bugs to find how many insects of each type you have. Them you will have to find the economic threshold for spraying that pest. The Canada Canola Council has economic threshold numbers for different insects. If the numbers found are below the economic threshold, it will cost you more to kill them than the crop saved is worth. Another consideration is that insecticides kill beneficial insects as well as pests, and that all these insects are part of the larger food chain.
For more information please Call SVF.
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