Lygus populations continue to be high and exceed thresholds in parts of Alberta and Manitoba (around Morris and Altona). Once pods become leathery (role of thumb is about two weeks before swathing), then even adult lygus cannot cause damage and control is not economical. Economic control thresholds for lygus bugs are based on adult and late instar counts. When canola…
Insects
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Quite high populations of lygus are being found in parts of the Peace and southern and central Alberta (finding as many as 80 lygus per 10 sweeps with approximately 25 to 30% of those being adults with the remainder a range of instar stages). Sweep net results also seem to be variable…
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Bertha armyworm can be found in most fields in the central Peace with about 25% of the fields exceeding threshold and requiring spraying (around Lacrete and Fort Vermillion). Spraying is also happening in pockets in eastern Saskatchewan (south of highway 16 and east of highway 11) and in northern areas around Delisle and North Battleford…
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Parts of the Swan River Valley were spraying for Bertha last week and now are contending with diamondback moth. Second generation larva and cocoons are being found in other areas (Arborg in Manitoba and parts of north and eastern Saskatchewan) and these populations continue to be monitored. The threshold for diamondback larvae is 200 per meter square at today’s canola…
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Numbers of adults in southern Alberta range between 3 to 4 per sweep but the majority of fields are completely out of flower. Spraying this late in the season is not economical because…
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Cabbageworm larva populations are quite heavy in the central corridor on the western side of Saskatchewan and unprecedented amounts of adults can be found…
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Parts of the Peace are seeing grasshoppers migrate from other crops into field edges…
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Economic spray thresholds are calculated based on individual species. We don’t have scientific evidence to combine thresholds, but where an “additive” effect of multiple species can make sense is when more than one species are feeding on key yield-producing areas — flowers, buds and pods — at the same time. For example, if you have lygus bug and cabbage seedpod…