Root maggot

  • Root maggot scouting

    Root maggot

    You might be seeing more root maggots this year, but they're not really something that can be controlled in crop.

    General wilting is likely environmental, but patches or individual plants could have some other cause. Dig them up carefully and look at their roots for clubroot galls, root diseases and cabbage root maggots.

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  • Insect update: Grasshoppers, lygus, cabbage seedpod weevil

    Root maggot

    grasshopper feeding small

    Grasshoppers may be above thresholds in some fields. The nominal threshold for grasshoppers in canola is 8-12 per square metre, although the higher end of that range may be more appropriate in a typical canola crop. Grasshoppers are often at higher numbers at field margins, making a targeted spray possible. Scout to see where that line is.

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  • Rotations and risk management

    Root maggot

    Blackleg disease rating: 2

    Scientific research in Western Canada has identified three factors that increase the risk of canola yield loss in short rotations. They are blackleg (shown above), clubroot and cabbage root maggot.

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  • Insect update: Beneficials, CSPW, root maggots

    Root maggot

    Banchus is a parasitoid of bertha armyworm. It can be harmed by unnecessary insecticide sprays. Source: Lloyd Dosdall

    Beneficials. Lygus, bertha armyworm and diamondback moth have a number of natural enemies that will keep populations in check. These beneficial insects may not control an immediate pest threat that has already exceeded thresholds — growers will still have to spray in that case — but beneficials can keep a lid on populations. The key to preserving beneficial insects is to follow thresholds and spray only when necessary. Click here for beneficials to look for while scouting.

    Read more for updates on cabbage seedpod weevil, cabbage root maggot and others….

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  • Root maggots and disease

    Root maggot

    Root maggots can increase dramatically in canola on canola rotations.

    Root maggots and root disease often show up together in the same field. Root maggots are white and up to 10 mm (half an inch) long — just like maggots. Maggot feeding can damage root crowns and impede water movement, causing wilting. Severe feeding can cause plant death.

    Severe root maggot damage can occur in fields with back to back to back canola — another reason to rotate crops. Here’s an excerpt from an article Jay Whetter wrote for Crops Guide magazine in 2012 that may explain the situation…

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  • Root maggot, root disease in back to back canola

    Root maggot

    An AAFC study has shown very clearly that with continuous canola, there is a statistically significant increase in crop damage by root maggots. No insecticides are available to control root maggot in canola, but providing a one year break seems to make a significant reduction in root maggot losses, the study found.

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  • Insect update

    Root maggot

    Cabbage seedpod weevil adults have arrived and are feeding on volunteer canola at the bloom stage in southern Alberta and southwest Saskatchewan. Weevils move to canola fields at the bud to early flower stages. Growers should start scouting.

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  • Insect update

    Root maggot

    Flea beetle spraying continues in Manitoba where crops are advancing slowly due to excess rain and limited warmth. Redbacked cutworms are still causing severe damage in southern Alberta. Some sprayed fields need to be reseeded.

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