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Late season spraying – adhere to pre-harvest intervals
Pre-harvest interval (PHI) refers to the number of days that the crop should NOT be harvested after application of a pesticide. Harvest in this context means cutting or swathing, so this could also be called the pre-cutting interval. If the crop is harvested before the indicated interval has elapsed, there could be unsafe or unacceptable residues of the pesticide remaining in or on the harvested seeds. Pre-harvest intervals are listed on the labels of pesticides and under the ‘Restrictions’ section of individual product descriptions in provincial guides to crop protection. Take note of the required pre-harvest interval and allow adequate time before harvest. Also, ensure that the product is registered for the intended use and registered to be used on the crop at that stage. Following pre-harvest intervals is critical to keeping all canola Export Ready.
Keep scouting for late-season insects
Lygus bug populations at or above economic thresholds have been found in the highway 2 and 23 corridor (north of Lethbridge and south of Calgary) and in central areas around Olds, Boyle and Barrhead. Farmers near Provost and Two Hills are battling high populations of lygus, diamondback moth and bertha armyworm. Click here to see threshold tables for key insects. Be Export Ready and keep PHI top-of-mind when choosing a late-season treatment. For more on PHI, listen to Denise Maurice, CCC vice president of Crop Production, speaking on ACPC radio. Or click your province for a link to your guide to crop protection: Alberta Saskatchewan Manitoba
Click here to hear a radio interview on diamondback moth and its natural enemy with Dr. Lloyd Dosdall, University of Alberta. Click here to sign up for a Diamondback Webinar discussing diamondback biology and its control with Dr. Dosdall to be held Thursday August 12 at 8:30 am.
Don’t rush to swath
Swathing at 50 to 60% seed colour change on the main stem is generally optimal for both yield and quality. If growers can’t wait that long, at a minimum make sure green seeds are firm when rolled between the thumb and forefinger. Swathing prior to 15% to 20% seed colour change will likely reduce yield potential and could contribute to green seed issues under hot and/or dry conditions. Hot, dry conditions in Manitoba this past week caused significant pod colour change in some fields. Sun scald or natural senescence is making the canopy look ripened but often the seeds within remain green. Be sure to examine seeds within the pods on the main stem to gauge timing accurately.
For more on swathing timing, click here to see a CCC video.
Pre-harvest weed control
With swathing imminent in many regions, there are lots of questions about pre-harvest weed control vs. desiccation. Glyphosate is not a desiccant and will not hasten seed maturity. Glyphosate for pre-harvest weed control in canola should be applied at 30% seed moisture which is about 30 to 40% seed colour change. Apply 7 days before swathing for full translocation within the target weeds, generally Canada thistle and quackgrass. Research has shown that post-harvest can be the best time to control dandelion. This year’s thin fields have high weed populations in some cases. If desiccation is required to manage uneven maturity in glyphosate tolerant crops, Reglone can be applied but will only provide top-growth dry down for weeds. Scout fields thoroughly to know what weeds are present and what product or timing is needed.
Condition and cool after combining
It is critical to cool and condition canola after putting it in the bin. Canola binned at high temperatures, even at seed moisture levels considered dry, can begin to spoil in storage. Crops with lots of green material present (weeds or less mature low spots) can have a high chaff load and quickly start to heat when stored. Use aeration to bring down the temperature and/or moisture of binned canola to below 15 °C and 8% moisture for long term storage.
**ARTICLES**
Growers needed for combine loss study. As part of a CCC-funded project, researchers are looking for growers in select regions to take part in a combine-loss survey. Growers remain anonymous and researchers do most of the work. Growers around Lacombe and Edmonton,click here for more information. Growers around Saskatoon, click here. And growers around Winnipeg, click here.