July 12, 2017 – Issue 16

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  • Canola Watch quiz: Sweep net contents

    What’s in your sweep net?


  • Sclerotinia stem rot and hot weather

    Hot weather during flowering can increase flower and pod abortion and reduce overall yield potential. Return on investment from a fungicide applications is more likely if yield potential is at least 30 bu./ac., with ROI going up as yields increase beyond that threshold.


  • Diamondback moth: Thresholds and scouting tips

    Thresholds for diamondback moth larvae are 100-150 larvae per square meter in immature to flowering plants and 200-300 larvae per square meter in plants with flowers and pods.


  • Lygus bugs: Thresholds and scouting tips

    Lygus. Credit: Dan Johnson

    In very dry conditions: 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 (0.5 per sweep).
    In moist and high-yield conditions: The economic threshold is quite a bit higher. At early pod stage, 50 lygus per 10 sweeps (5 per sweep) could cause a 2 bu./ac. reduction in yield.


  • Proper sweep net technique

    Thresholds for lygus bugs and cabbage seedpod weevil are based on a specific sweep net technique. If you’re not doing a complete 180° pattern, walking while you sweep, and keeping the net near the top of the canopy, your counts could be significantly different from someone using the recommended techniques. Here are the recommended sweep […]


  • Heat, drought and other reasons for missing pods

    As canola starts to move from flowering and into pod formation, growers will often notice blanks up the raceme where pods did not form. Heat and drought would be common reasons this year.


  • Sad- or odd-looking buds, flowers and pods

    While scouting for flower staging, canopy moisture and pod-feeding insects, also take a look for deformed buds and growing points, small pale flowers and anything else unusual. Over the years, Canola Watch has written about all kinds of potential causes for a wide range of symptoms at the reproductive stage. These include….


  • Shorts on canola silage, hail and more

    With prolonged dry conditions and recent hot weather, yield potential has dropped to very low levels in some fields. One CCC agronomist this week had a conversation about cutting this canola for silage. For a helpful link and more important shorts…


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