August 28, 2013 – Issue 22

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  • Issues of the week


    Serious disease infections become more obvious as fields get closer to harvest. Whitened diseased and dying plants are in stark contrast to the healthy light green plants around them. Take time now to identify which disease is responsible. This is essential for management next year.

    Late canola fields may be at continued and higher risk for bertha armyworm feeding, especially if most other fields are swathed and “armies” of worms are marching in search of still-green plants. No need to panic however. Check fields, and spray only at thresholds.

    Look at seed colour change before swathing. Swathing at 10-20% seed colour change (SCC) can cost 10-15% of yield when compared to waiting to swath at 50-60% SCC. At 60% SCC, seeds are fuller and bigger and more seeds on the plant have reached physiological maturity, hence the higher yield.

    Early canola fields are being combined this week in the heat. Hot canola should be aerated immediately, even if it’s dry.

    Follow the CCC agronomy specialists on Twitter. Find their Twitter names here. Tweet of the week:

    Tweet of the week August 28


  • August 28 quiz

    August 28 quiz

    Here are three diseased stems. What pathogen caused each?


  • Top 10 tips to reduce combine losses


    Growers can lose up to 5 bu./ac. of canola during harvest, with many of those losses occurring as canola enters and exits the combine. Combine losses should be less than 1 bu./ac., and hopefully more like half a bushel.

    Here are the top 10 tips to keep combine losses to a minimum…


  • Cut too green and lose 19% of yield

    Summary results pooled for both 3 and 5 lb/ac seeding rates at all locations based on similar trends observed. Straight cut treatments at 10 of 12 locations produced relative yield of 107% vs 30-40% SCC.

    Research conducted by the Canola Council of Canada over approximately 28 site-years indicates that significant yield increases can be achieved by waiting until 50-60% seed colour change on the main stem before swathing. Swathing at 50-60% SCC resulted in 8% more yield than swathing at 30-40% SCC, 12% more yield than at 10-20% SCC, and 19% more yield than swathing before 10% SCC.


  • How to determine overall seed-colour change

    All these seeds would be considered "changed."

    The optimal swath timing for canola yield and quality is when 60% of seeds on the main stem are showing some colour change. Seed colour change (SCC) is considered any amount of yellow or brown on the seed.


  • How to tell blackleg, sclerotinia and clubroot apart

    Sclerotinia on stem at harvest time.

    Sclerotinia stem rot (above) and blackleg can both cause what looks like pre-mature ripening. Both diseases, when severe, can cut off nutrient flow up the stem, resulting in a whitened dead plant. Both can cause increased lodging. However, long-term management requires an accurate identification of which disease is the cause. Disease identification will make sure you make the correct seed and rotation decisions for next year.

    Here’s what to look for just before harvest:


  • Late canola faces higher bertha armyworm risk

    Mature bertha armyworm. Source: Roy Ellis

    Bertha armyworm got its name because the worms will march like an army in search of food. As canola crops dry down and are swathed, bertha armyworms that have not pupated will keep moving in search of lush green plant material. Late canola fields could be in the crosshairs of this army.


  • Late-season flea beetles

    Flea beetle numbers this late in the season are higher than we’ve seen in years, which could point to higher numbers next spring.

    For this year’s canola crops, don’t take any action unless you see flea beetles feeding on pods over a broad number of acres. Entomologists have not set thresholds for late season flea beetle feeding, but it’s generally believed that numbers have to be very high — perhaps 100 per plant — before economic losses occur.


  • Tips to reduce wind damage to swaths

    wind blown swaths

    Thin crops and high winds can lead to heavy shattering losses if swaths start to roll. Here are tips to reduce potential losses from swaths blowing:


  • Straight combining thin crops

    The ideal canola crop for straight combining is thick and well-knitted with even maturity. However, a case can be made for straight combining very thin crops with uneven maturity….


  • How to measure combine losses

    Combine loss pan, dropped_opt

    Canola growers can lose up to 5 bushels or more per acre if the combine isn’t adjusted properly. Here are tips to limit those losses.


  • Aerate canola combined hot

    When using aeration to cool canola that is very dry, fans can be shut off during the day and turned on at night when air is cooler.

    Canola combined this week could go in the bin very hot. Canola storage experts recommend that hot canola be put on aeration for cooling, even if it’s dry. There will still be convection currents and some moisture movement within the bin, which can concentrate moisture at the bottom of the central core — creating a possible start point for heating.


  • Fall weed control in fields planned for canola in 2014

    Overwintering dandelions can be a host for aster yellows phytoplasma.

    Growers planning post harvest weed control to clean up fields planned for canola in 2014, take these steps for improved control and to avoid herbicide carryover damage in canola.


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