July 24, 2013 – Issue 17

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  • Issues of the week

    bertha armyworm mixed small

    Insect scouting is the top priority as canola moves out of flowering and into podding. Protection from insects, using economic thresholds, is most important at this stage as canola no longer has the capacity to compensate for losses. The photo above shows the various colours of bertha armyworm.

    While scouting for insects, take a look at plants for early signs of blackleg, clubroot and sclerotinia stem rot. Nothing can be done to mitigate losses at this stage, but identifying which diseases are present is relatively easy between now and harvest. Scouting now provides the opportunity — if diseases are present — to modify management plans in subsequent years.

    If you start to see problems show up, be wary of product claims such as, “If you had sprayed our product in June you wouldn’t be seeing that right now.” Get a few opinions, if necessary, to accurately identify problems. Try the Canola Diagnostic Tool at www.canoladiagnostictool.ca. Keep notes. And prepare to use proven remedies next year.

    A few noteworthy events are coming up: Disease Scouting Clinic in Portage la Prairie, Manitoba July 30; Crop Diagnostic School in Indian Head, Saskatchewan July 30-31; and the Clubroot Galla in Brooks, Alberta July 31-August 1.

    Follow @CanolaWatch on Twitter. Here’s the canola tweet of the week:

    Tweet of the week July 24


  • Canola Watch quiz

    Quiz July 24

    You find bertha armyworms at economic thresholds and you plan to spray. Before spraying, you need to estimate how many days it will be before you cut the crop. Why?


  • Top 10 things to consider when scouting for insects

    3. Record what you find. With detailed records, including insects found in each field, insect numbers, what they’re feeding on, time of day, temperature and weather conditions, you know which fields to scout more frequently, and you have comparison points for other fields and other years. 2. Follow thresholds. Every major insect of pest of canola has an economic control threshold. See the table below.
    1. Pre-harvest intervals. If spraying is necessary, choose a product with a pre-harvest interval that fits within the timeframe between spraying and cutting the crop.


  • Insect update — Bertha armyworm, thrips

    Thrips feeding can lead to curled pods.

    Thrips damage shows up in some fields. Bertha armyworms are the bigger issue, with adult counts continuing to build and many areas now at moderate risk, or higher. Read more to see links to latest maps and counts.


  • Scouting late July for disease

    Sclerotinia stem rot infection starts as leaf or stem infection around a rotting petal.

    The window to control disease in canola is closed, so why scout? Well, because the period from podding to harvest is the easiest time to see diseases. And if you can identify which diseases are present, you can adjust your variety choice, crop rotation and fungicide use for subsequent years.


  • Coming events

    Read more for crop walks and diagnostic schools in July.


Canola Watch