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You may be sick of reading about it, but that’s better than being sick of finding it. Lygus bug continues to be a hot topic for growers in a number of locations across the prairies. While numbers are surprisingly high, they may still not be high enough to warrant the cost of spraying. Don’t let the idea of revenge influence…
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Lygus bugs are still at high numbers in some regions, mostly in Alberta. If sweep netting shows high lygus numbers, here are five considerations before spraying…
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Lygus hotspots: Lygus numbers are high in some regions, with reports of 70+ per 10 sweeps in some fields in central and northern Alberta. Some fields will warrant a spray, but seeing the plane next door does not mean all canola in the area should get sprayed. Assess each field. Bertha armyworm hotspots: Berthas are a very low numbers in…
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Threshold tables for lygus suggest, for example, that if canola is $12 per bushel and spray costs $8 per acre, the threshold at the early pod stage is 5 lygus adults or late instar nymphs per 10 sweeps. Current thinking is that 5 lygus per 10 sweeps (0.5 per sweep) is too few to warrant a spray, and that the…
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Insecticide to control lygus present at the bud stage of canola is rarely effective or economical, and there is no threshold for this stage. Under good growing conditions, canola can grow through this early damage without any yield loss. In fact, lygus studies show that light early feeding on healthy canola crops can actually increase flowers and pods and, ultimately,…
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Bertha armyworms keep eating to within a few days of pupating. These 1.5” late-stage berthas eat much more than at smaller stages, doing a lot of damage in a week if numbers are at thresholds…
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Lygus counts are very high in some locations, but get out the sweep net and scout to be sure. If canola is $12 per bushel and application costs (insecticide and application) are $12 per acre, the economic threshold for lygus bugs is 8 per 10 sweeps at the end of flowering and 11 per 10 sweeps at the pod…
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Bertha armyworm adult trap counts suggest low to medium risk in most areas this year, with a couple higher risk hot spots in Saskatchewan — south of Regina being the largest. (See the map above.) Any need to spray is at least two weeks away. Larvae do the damage, and spraying should only occur if larvae feeding reaches threshold levels…
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Many canola fields have a combination of insects feeding on the crop. An “additive” effect is possible when more than one species are feeding on key yield-producing areas — flowers, buds or pods — at the same time. For example, lygus and cabbage seedpod weevil have been found in the same fields in the southern Prairies this week. Preliminary results…
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