July 10, 2013 – Issue 15

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  • Issues of the Week

    Hail LethbridgeJuly7 Autum

    Hail struck a number of areas over the past week, and canola damage ranged from light to total destruction. The photo above shows a couple hailstones collected around Lethbridge this week. Canola has a remarkable capacity to recover from light hail at early flowering — although if the flowering period is extended as a result, the crop may benefit from a second fungicide application.

    Sclerotinia stem rot management continues this week. The ideal fungicide timing is 20-30% flowering. Crops most likely to provide a return on investment have had moisture (even average moisture is ample) before and during flowering, a humid canopy, and 30+ bu./ac. yield potential. The window closes for fungicide application at 50% flowering.

    The most damaging time for insect feeding is late flowering and through pod fill when canola plants have little capacity to recover. Lygus, diamondback moth and bertha armyworm are the big ones to watch during this period. Adult scouting continues for bertha armyworm. Diamondback larvae are starting to appear in fields at low levels. Lygus numbers are building in some areas, and in rare cases, an application during flowering may be needed to move the crop along.

    Lygus and adult cabbage seedpod weevil feeding during the bud stages is one possible reason for missing pods. Growers seeing missing pods on canola stems may be inclined to blame last week’s heat, but insects or something else may have been at work before the heatwave. Click here for more reasons for missing pods.

    Tweet of the week:
    Tweet of the week July 10
    Follow @CanolaWatch and the CCC agronomy team on Twitter.

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  • Canola Watch quiz

    July 10 quiz

    What caused this damage?

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  • Top 10 reasons not to go fishing this week

    10. Crops are in the 20-50% flowering window, yield potential is OK, there’s moisture in the canopy and you have sclerotinia spraying to do.
    9. Cabbage seedpod weevils have moved into your area for the first time, and you have to do sweep netting to see if thresholds are at 2 per sweep.
    8. Hail rolled through and you have to check fields for damage levels.
    7.This is a great time of year to attend a local canola tour or extension event.
    6. We’ve got nothing for this spot.
    5. Still nothing.
    4. Nothing
    3. Nothing
    2. Check #ABbugchat on Twitter just to make sure you haven’t missed anything.
    1. Oh heck, set aside a day and go fishing. You deserve a break.

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  • Hail at flowering

    Yield loss will be lower if hail hits before flowering than at late flowering. Source: Canola Growers Manual

    Canola is quite resilient to light hail at up to 20% flower. The crop can flower longer to compensate, and may recover with only minimal to moderate yield loss. Canola has also shown remarkable recovery from more intense hail at 20% flower. However, a crop flattened by hail is unlikely to recover. If regrowth occurs, which is possible, plants are set back so far that maturity becomes a major factor.

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  • Insect update

    BAW Saskatchewan map

    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. Note that even in areas deemed low risk by adult counts, isolated areas of heavy larvae feeding can occur. Don’t completely let your guard down even if adult numbers are low.

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  • Root maggots and disease

    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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  • Biologicial fungicide: Serenade use tips

    Because Serenade works differently from other fungicides, we want to share these instructions for best results, as provided by Bayer CropScience:

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