Crop development in most areas has continued to advance significantly due to hot and dry conditions. Swathing is virtually complete across Manitoba, and almost complete throughout Saskatchewan with just later seeded fields remaining to be swathed. Swathing progress in Alberta ranges from 10-80% complete with the southern and eastern areas farthest advanced, but just beginning in whereas western areas (west of Hwy. 2 corridor). Combining is close to wrapping up in many areas of Manitoba, except the northwest, which is just underway. Combining progress across Saskatchewan ranges from 40% complete in the northwest to just underway in northern areas. In Alberta, combining is least advanced with up to 70% complete in dryland areas of the south, but just swathing is just underway in many other areas.
Growers continue to ask about the proper stage to swath. The typical recommendation is to begin swathing when the plant has reached approximately 20% seed colour change (SCC). Swath the majority of the crop at or near the recommended time for optimum seed yield and quality. The optimum time is when the average seed moisture content is 30-40% or the whole plant has reached about 35% seed colour change (SCC). To learn more about proper field assessment, refer to the Canola Council publication "Time of Swathing Guide" or visit our Web site.
Under the current hot and dry conditions, SCC can be rapid, as much as 10% or more per day. Be aware that following typical recommendations for stage of swathing may not be appropriate under these conditions. Swathing in hot (high 20’s to 30oC temperatures), dry and windy conditions may stop chlorophyll clearing due to rapid desiccation of swaths. This may result in some green seed problems since the enzyme responsible for clearing the chlorophyll requires moisture. Smaller, less mature seed can also shrivel up, resulting in throw-over during combining and lost yield. Consider delaying swathing to ensure that the bulk of the crop has reached at least 30% SCC. This may help reduce potential yield and quality losses in these situations. Swath during the cool evening hours, at night, or early in the morning to allow the seed to dry down at a slower rate and further reduce the risk of both green seed and shattering.
However, as the season advances, temperatures begin to drop, which brings the potential risk from fall frost. If frost conditions are likely in the near term, consider swathing early (as early as 10% SCC) to allow plants to dry down somewhat and reduce the risk of frost causing green seed problems.
Uneven crop maturity, either among plants or through increased branching due to lower plant densities, can make judging when to swath more difficult. Proper assessment of a field involves checking maturity in several areas, i to determine not only the average maturity but also the proportion of plants at various growth stages. If a large proportion of the plants are at the same stage, judge time of swathing based on the maturity of those plants. However, it may not be clear which plants will produce the majority of the yield. In this case, wait a few days after the most mature plants are ready to swath to allow less mature plants or branches to ripen, at least beyond the stage where the seed is still translucent. This will reduce the chances of green seed problems and yield losses.
Keep in mind that seed colour change is very different from pod colour change. During recent hot weather, many fields have experienced sun scalding or pod bleaching that may cause the crop to appear mature. Insect damage and varietal differences will also contribute to the ripening appearance of canola fields. It is important not to be fooled by the colour of the straw and/or pods. Pods that appear ripe and ready to swath may still have green and translucent seeds. Conversely, pods that do not appear ripe may contain mature seeds that have changed colour. Walk fields and examine seeds within pods to properly assess crop maturity.
Insects continue to be a problem in many areas. Grasshoppers continue to damage crops as they move from ripe cereal crops into green canola fields, although the risk is lessened as the crop matures and is cut. High flea beetle numbers continue to be found throughout much of Manitoba, Saskatchewan and southern and eastern Alberta.
For fields that are either currently being swathed or have been swathed very recently, post swathing scouting can be very useful, particularly if plants have developed poorly or ripened prematurely. It’s an opportune time to add valuable information to the farm records that may influence some decision making in the upcoming season. Be on the lookout for weeds, insects and disease incidence. Current weed identification can help plan for weed control next spring. This is also a critical time for insect pressure and may give an indication of future pressures. For example, high flea beetle numbers this fall may indicate similar pressures next spring. As a result, consider seed treatments with extended flea beetle control. Scouting for disease is also very important during this time. Proper identification and assessment of disease incidence may be valuable information for next year’s crop when assessing potential risk. For more information on some of the diseases that may be observed following swathing, see the following links:
Sclerotinia
Blackleg
Graystem
Brown girdling
root rot
Clubroot
Fusarium wilt: http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/prm2446?opendocument
Growers scouting fields planted to a canola variety rated moderately resistant (MR) or resistant (R) and find blackleg infected plants, are asked to send the infected plants to Dr. Dilantha Fernando. To submit a sample, cut the stem 2" (5 cm) on either side of the lesion, put the cutting in a paper bag (not a plastic bag) and mail it to: Dilantha Fernando, Department of Plant Science, University of Manitoba, Winnipeg, MB, R3T 2N2. For more information, call him at 204-474-6072 or e-mail fernando@ms.umanitoba.ca. University researchers are studying the blackleg races present to determine whether any have overcome the resistance in current varieties.
For those growers combining canola during warm temperatures, canola storage can also be a concern. Be aware that canola binned at high temperatures may be susceptible to heating and spoilage even though it may test dry, particularly if it contains green material such as weed seeds or chaff. Use aeration to bring down the temperature of the binned canola. For more information on safe storage conditions, check the following link.
Under average weather conditions, canola can typically be ready to combine in 10 days to two weeks after swathing. This time period is normally required for the seed to properly cure and clear green seed. Under the hot, dry and windy conditions experienced in many areas, the crop may dry down much faster than normal. However, the chlorophyll in the seed may not have had a chance to clear adequately. Under these conditions, consider leaving the crop in the swaths for a longer period of time to allow the chlorophyll to clear properly.
Direct overall questions regarding this report to John Mayko, Agronomic Research & Extension Manager, maykoj@canola-council.org, ph/fax: 780-764-2593.
For specific questions regarding regional
issues associated with this report, please
consult one of the following Canola Council
of Canada regional agronomists or provincial
oilseed specialists:
Derwyn Hammond, Agronomist, Manitoba, hammondd@canola-council.org,
204-729-9011
Rob Park, Manitoba Agriculture & Food,
rpark@gov.mb.ca,
204-745-5665
David Blais, Agronomist, Western Saskatchewan,
blaisd@canola-council.org,
306-895-2122
David Vanthuyne, Agronomist, Eastern Saskatchewan,
vanthuyd@canola-council.org,
306-782-7799
Jim Bessel, Senior Agronomist, Northeastern
Saskatchewan, besselj@canola-council.org,
306-373-6771
Bill Greuel, Saskatchewan Agriculture, Food
& Rural Revitalization, wgreuel@agr.gov.sk.ca,
306-787-2756
Doug Moisey, Agronomist, Central & Southern
Alberta, moiseyd@canola-council.org,
403-553-2829
Christine Mardell, Agronomist, Peace River
Region, mardellc@canola-council.org,
780-518-1513
Murray Hartman, Alberta Agriculture, Food
& Rural Development, murray.hartman@gov.ab.ca,
403-782-8024
Kerry Clark, BC Ministry of Agriculture,
Food & Fisheries, Kerry.Clark@gems9.gov.bc.ca,
250-787-3213
The Canola Crop Watch Report provides just-in-time information on canola production to growers and industry. Contributors to the Canola Agronomy Network are:
Manitoba Agriculture & Food, Manitoba Canola Growers Association, Agricore United, Cargill, James Richardson International, Saskatchewan Wheat Pool, United Farmers of Alberta, Saskatchewan Agriculture, Food & Rural Revitalization, Saskatchewan Canola Growers Association, Saskatchewan Canola Development Commission, Alberta Agriculture, Food & Rural Development, Alberta Canola Producers Commission, BC Ministry of Agriculture, Food & Fisheries, and the Canola Council of Canada.