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In parts of central Alberta, lygus counts continue to exceed thresholds significantly (with counts as high as 450 lygus in 10 sweeps in some fields). In other areas, lygus numbers are just at or approaching threshold but the crop is very near to swathing. With these counts, growers are encouraged to resist the urge to simply spray and to be…
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Scouting for bertha armyworm can be tricky when scouting during the heat of the day. Click here to view a short scouting video with Canola Council Agronomist Tiffany Martinka. It……
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When sweep netting for lygus (shown above), it may seem that there are more lygus in the field than end up in the sweep net. This is expected. Sweep net thresholds were establishing knowing that lygus in the sweep nets represented only a certain percentage of lygus in the canopy. Stick to the thresholds, and follow sweep net techniques outlined…
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Second generation lygus have arrived. Young nymphs will reach late instar and adult stages in 5 to 14 days. When scouting to see if lygus numbers are near thresholds, include later instars — the ones with black dots on their back — as well as adults in the count. Bertha armyworm larvae are starting to feed in some locations…
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Include nymphs (shown above) when doing lygus sweep net counts. Bertha risk rising. Zebra caterpillers are usually confined to small areas within a field. (Photo source: Roy Ellis)…
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Our current economic threshold tables for lygus in canola may be too low when applied to current canola production systems across the Prairies. If a canola stand is healthy and growing fast, growers are reportedly doubling or tripling thresholds. Say the threshold is 10 per 10 sweeps, some growers are doubling that to 20 per 10 sweeps as the action…
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If you have lygus bug and cabbage seedpod weevil in the same field and if they are both at 50% or more of their economic spray thresholds, spraying may provide an economic benefit…
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Check to see if lygus feeding is preventing crop from coming into flower. Bertha armyworm adults are mounting and larvae will start to hatch later this month. Leafhoppers are at higher than usual numbers in some locations…
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Insecticide control at the bud stage is rarely effective or economical even when counts are 15-20 per 10 sweeps. Under good growing conditions, canola can grow through this early damage without any yield loss. In some cases canola can actually yield more if some early bud feeding occurs. Lygus control at the bud stage may be warranted if all buds…
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