Alberta Barley

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Wireworm

Wireworm numbers in Alberta have increased in the past few years, and the pest has started to pose serious problems for barley growers.

Wireworms feed on germinating seeds and burrow into seedlings during the three to four years it takes for them to reach their adult stage, remaining underground throughout that time. This often makes them difficult to detect until they’ve caused considerable visible crop damage.

Seed treatments are the only available chemical method of combating wireworms. However, seed treatments will only subdue the wireworms long enough to allow the crop to become established.

Prevention/management tips:

  • Delay seeding slightly, so that the crop will emerge quicker
  • Seed as shallow as possible into a warm, moist seedbed
  • Increase seeding rate by 15–20%. Because wireworms actually have to feed to ingest the insecticide seed treatment, plant loss will occur.
  • Include a legume or pulse crop in rotation with cereals and oilseeds. This will gradually reduce wireworm populations, as these crops are more resistant to wireworms and are not preferred for click beetle egg laying.
  • Use treated seed. There is no way to treat for wireworms in an emergent crop, and damage is often noticed too late for reseeding.

Wireworm baiting:

  • Mix 1 to 1 ½ cups of oatmeal or wheat flour with two tablespoons of honey and up to ½ a cup of water until the mixture sticks together enough to make a ball
  • The balls can be placed directly in the ground, or tied up in a mesh bag (old socks or cheesecloth work well, too)
  • Bury the balls in 4–6 inch deep holes, and mark them with flags
  • Place roughly 20 evenly spaced bait balls per acre for best results.
  • Check the bait balls for wireworms every 4–5 days
  • Make sure there are no competing sources of CO2 (green manure, living plants, etc.) within one metre of the bait. If wireworms are sufficiently fed they will not be attracted by the presence of a new food source and will not go for the bait.

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