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Story Posted: June 16, 2010 Canola Watch 8: Take action on weeds and cutworms In This Issue: Yellow canola: Wait for moisture stress to ease, Fertilizer top up in good conditions, Cutworm threat to extend into July, Tank mixing herbicides with insecticides, Questions and contacts. Issues of the week Crop and weather update Alberta: Many parts of southern Alberta are still dealing with excess moisture. Hardest hit was the Coronation area with another 4". North of Edmonton got little more than a tenth. With a couple days of heat in the past week, many Alberta canola fields went from 20% ground cover to complete canopy. Earliest seeded canola has moved past the 4-leaf stage. Read the Alberta crop report. Saskatchewan: It's like two worlds. The west looks pretty good so far, with 99% of fields seeded and a good start for the crop. The east is deluged, with heavy rains again this week. CCC agronomy specialist Tiffany Martinka says around Melfort there is one acre underwater for every acre seeded. With final crop insurance deadlines this weekend, most acres unseeded as of today will remain unseeded. Read the Saskatchewan crop report. Manitoba: In the west and northwest, 10% to 15% of acres are unseeded and likely won't get seeded with crop insurance deadlines passed. Many canola crops across the province are saturated and show moisture stress. Crystal City area had some hail, but at this early stage the canola should recover. Read the Manitoba crop report. Quick Hitters Manitoba Agriculture, Food and Rural Initiatives has revised the glyphosate chart we attached to Canola Watch 3. Click here for the revised PDF file. If you printed out the original, replace it with the new version. The chart includes all glyphosate products available, including amount of active ingredient per litre, salt type and container size. Mistaken diagnosis: Gophers ate 100 acres of canola around Sedgewick, Alta. The grower thought it might be cutworm, but with scouting discovered the real culprit. Strychnine baits and, in some jurisdictions, mix-it-yourself strychnine liquid is available for gopher control. Talk to your municipal or county office for options in your area.
Sclerotinia risk: With all this moisture, many growers and retailers have asked us if that means a higher sclerotinia stem rot risk. It depends. Sclerotinia sclerotia do not tolerate saturated soils, so very wet conditions could reduce the apothecia germination and spore production from those fields. But in areas with good moisture and great yield potential, canola may be at higher risk. When flowering starts, use the CCC's Canola Disease Scouting & Risk Assessment Card to help determine whether a spray is warranted. Ruts in the field: Wider tires and lower tire pressures can improve sprayer flotation and reduce rut depth, but if the operator doesn't have time to switch tires, then keep in mind the desired harvest direction before spraying a wet field. Make ruts parallel with the intended direction of travel for the swather and combine so growers can keep up their harvest speed. Coming Event: CCC senior agronomy specialist Doug Moisey (click to email Doug)will lead a diagnostic tour June 22 at Lakeland Agricultural Research Association's site at Fort Kent, Alta. The tour runs from 12:00 to 3:00 and lunch is included. Call 780-826-7260 to register. Coming Event: AAFC's research centre in Lacombe is hosting a canola research tour Wednesday, June 30 from 9:30 a.m. to 3:30 p.m. Pre-registration is required. Lunch is included. Click here for more information and to register. Coming Event: The Crop Diagnostic School in Carman, Manitoba will run July 6 to 9 and July 12 to 16. Attendance for a number of those days is already full. Click here for more information and to register. Yellow canola: Wait for moisture stress to ease Topdressing fertilizer may help when new green leaves start growing and when good growing conditions return. Sulphur in the form of ammonium sulphate can provide an economic return when applied up to the bolting stage. Nitrogen applied past the 6-leaf stage is unlikely to provide an economic benefit. Tissue tests to determine nutrient deficiency may be unreliable this year in areas suffering unusual moisture stress.
Fertilizer top up in good conditions Growers may still see a benefit from the sulphur-nitrogen combination in ammonium sulphate. In western Saskatchewan, Clint Jurke (click to email Clint), CCC agronomy specialist has noticed sulphur deficiency in some canola this year, particularly in well-drained land where rains washed sulphur lower in the soil profile, below the depth shallow roots can access. Field conditions critical: If canola is growing in excessively wet conditions, yellowing and purpling may be the result of moisture stress .But if soil conditions are good, discolouration may be the result of nutrient deficiency. Factors to consider: Nitrogen topdressing can extend the vegetative period and delay crop maturity. Consider the calendar date and the fall frost risk when making a nitrogen top up decision. As canola plants grow their roots will start to access sulphur reserves that moisture carried lower into the soil profile. Growers who have been applying recommended rates of sulphur may find that topdress may have a lower economic return than those who have cut sulphur rates. Cutworm threat to extend into July Assessing the risk: Cutworms tend to be more numerous on fields that had a lot of green and growing plants (including weeds) the previous fall, and that had been in pulses the year before. Cutworms can reach economic levels regardless of the previous crop. Scout all your canola fields. Crop damage: Look for cut, wilted or missing canola plants. Cutworms are often in patches, so spot spraying affected acres may be enough. Evening spraying is optimal as cutworms come closer to the surface at night. Morning sprays are less effective as cutworms move deeper at first light of day. For more scouting and spraying tips, click here for a MAFRI factsheet. Check insecticide labels to make sure a product works on cutworms.
Tank mixing herbicides with insecticides
Questions and contacts If you have questions on regional issues, contact one of the following Canola Council of Canada regional agronomists or provincial oilseed specialists:
This report is supported by each of the provincial canola grower associations. For more information on some of their activities, check out the following links:
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