In this issue (click the bookmark
links below to move to specific sections of this
report):
Crop development |
Hail | Flower
blast | Insects
| Sclerotinia
| Fusarium wilt
| Field scouting
| Swathing | Pre-harvest
glyphosate
The Alberta Canola Producers Commission (ACPC) has developed an Alberta focused version of this report. Visit the ACPC website at: http://www.canola.ab.ca
Crop
development remains varied across most of
the Prairies, ranging from full flower to nearly
mature. Manitoba has two crop stages, early planted
that has ended bloom and is well into podding,
and late planted fields that are in full flower.
Over half the crop in Saskatchewan has ended flowering
and is podding with the remainder in the latter
half of full bloom. Alberta crops range from nearly
mature for early seeded crops in southern Alberta
to end of bloom and podding in the central and
Peace regions. Soil moisture conditions varied
across most of western Canada with many areas
reporting adequate to ample moisture. However,
soil moisture has been depleted in many parts
of east-central and west-central Saskatchewan,
which may limit pod filling, especially with later
seeded crops. Dry conditions continue to be a
problem in areas of east central Alberta near
Hanna, Coronation and Castor, as well as the north
Peace between Manning and Fort Vermilion.
For current maps of moisture conditions across
western Canada, visit this PFRA page:
http://www.agr.gc.ca/pfra/drought/drprec7_e.htm
The latest crop report from Manitoba Agriculture,
Food & Rural Initiatives is available at:
http://web2.gov.mb.ca/agriculture/mwcr/index.php
The latest crop report from Saskatchewan Agriculture,
Food & Rural Revitalization is available at:
http://www.agr.gov.sk.ca/docs/reports/crop_report/crprpt040802.pdf
Additional moisture information for Alberta is
available from Alberta Environment at:
http://www3.gov.ab.ca/env/water/WS/data/precipmaps/weekly.pdf
Hail damage continues to be reported in many areas of western Canada. Damage was variable depending on the severity of the storm. Potential yield losses will depend on stage of crop and the severity of the damage. As the crop completes flowering and is into pod stage, hail damage becomes more irrecoverable. Hail damage also allows a point of entry for diseases such as sclerotinia stem rot, alternaria black spot and blackleg to infect canola plants. More information is available in the Canola Growers Manual (2003 edition) in Chapter 5, pages 511 and 512.
There
continue to be reports of flower blast
and poor pod development. During heat stress flowers
are less receptive to pollen, and the duration
of pollen release and viability is reduced. Air
temperatures in excess of 30°C
during flowering can result in flower abortion
and reduced pod formation. Gaps (no pod formation)
on the main stem are good indicators that flower
blasting has occurred. Hail, lack of available
sulphur or feeding from insects such as lygus
bugs and cabbage seedpod weevils may also result
in gaps on the main stem. More information is
available in the Canola Growers Manual in Chapter
5 pages 506 and 507.
Check this Canola Council page for a photo of
flower blast:
http://www.canola-council.org/images/canolablanks.jpg
Spraying for bertha armyworm larvae has been reported in the central Peace near Wanham and Eaglesham. Counts of 30 larvae/m2 and two to three larvae per plant have been reported. Most other areas are reporting low levels of insect activity. Grasshopper activity is increasing in parts of Manitoba and low levels of lygus bugs continue to be reported in Saskatchewan and Alberta, but no chemical control has been reported. However, it is very important to keep scouting for these insects as the crop finishes flowering and starts podding. It is at the early podding stage that the crop is most vulnerable to economic losses from these insects. It is also important to use proper techniques when scouting for various insects. Use a sweep net to determine thresholds for lygus. Economic thresholds may vary from 30 to 50 lygus in a 10-sweep sample. However, be aware of the lygus stage. If a large number of nymphs are very small (aphid-sized), wait a week and sample again. The larger the lygus the higher the potential damage. Also sample in the good areas of the field as higher numbers will be found in poor or thin areas. ‘Sap spots’ are also a good indicator of lygus damage. A sweep net cannot be used for determining thresholds for diamondback moth, bertha armyworm, beet webworm or alfalfa looper larvae. An estimation of the number of these larvae within a square meter is a more accurate method of determining thresholds for these insects.
For more background information
on bertha armyworm moth monitoring, check this
AAFRD sample map and discussion of how to interpret
the moth counts:
http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/prm2526?opendocument
The current bertha armyworm moth map can be found at:
http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/prm2526
For current trap count information in Saskatchewan:
http://www.agr.gov.sk.ca/docs/crops/
integrated_pest_management/insects/berthamap0107.asp
Sclerotinia
has been reported in early seeded fields in Manitoba,
Saskatchewan and southern and central Alberta.
Fungicide has been applied in many areas. Apothecia
continue to be reported in many of these areas.
Growers with late seeded canola may still benefit
from a fungicide application in areas with good
to excessive moisture and good crop growth.
Refer to the sclerotinia
checklist in the new Canola Growers Manual.
For the current list of recommended fungicides for sclerotinia control, check the 2006 Crop Protection Guide:
http://www.agr.gov.sk.ca/Docs/crops/CropProtGuideAddendum2006.pdf
Fusarium
wilt has been reported in fields near Vegreville,
AB. For more information on identifying fusarium
wilt, visit this page:
http://www.canola-council.org/fusarium.aspx
As the crop is nearing pod development, be vigilant in the frequency and intensity of field scouting. Watch for abnormal areas that have wilted or prematurely ripening plants within canola stands that are otherwise healthy. These areas may be early signs of diseases such as fusarium wilt, blackleg and clubroot that restrict water uptake by plants. Seed, fertilizer, and weed control costs have already been incurred. Do not forsake crop yield potential to mid and late season insects and diseases. Ensure that crop protection product application is at the earlier rather than later threshold stages of the crop. This helps to enhance product activity in most cases, reduce the stress on the crop from the pest, and maximize yield potential. When scouting fields be aware of what is causing the damage and be sure to properly document the information for future reference and decision-making aides. Scout for insects and diseases and nutrient deficiencies since these will become more evident as the crop matures. Pay close attention to misses, corners and overlaps or check strips to help determine if your fertility plan worked, and to help make important fertility decisions in the upcoming season.
Swathing is expected to start within the next week in southern Alberta and southwestern Saskatchewan. In the past year, time of swathing recommendations have been changed to reflect research results obtained after several years of Canola Production Centre trials. Recent research indicates that the optimum stage to swath for both yield and quality is up to 60% seed colour change. This enables many growers to start swathing at 30% to 40% seed colour change without sacrificing significant yield or quality. This widens the "swathing days" window for all growers, including those with large canola acreages. When conditions are hot (30°C) and dry, avoid swathing. Swath during the cool evening hours, at night or early morning to allow plants to dry down at a slower rate. This reduces the chance of green seed. If conditions are cool and it is late August or early September and frost is forecasted, swath at 10% seed colour change to minimize green seed.
The colour of mature plants and pods will vary between varieties as they mature. Some will appear ripe on the outside before the seeds are mature. Seed colour is more important than the overall plant/pod colour when determining the stage of maturity. When field topography, soil type and soil moisture levels are uneven, the flat areas of the field may have 30% seed colour change, hilltops 70%, and low lying areas 5% seed colour change. This will make the decision of when to swath more difficult. To learn more about proper field assessment, refer to the revised Canola Council publication "Time of swathing guide" or visit the Canola Council page.
With swath stage approaching, growers should consider a valuable weed control tool for next year's crop--pre-harvest glyphosate. It is the most consistent and effective treatment for many perennial weed problems. In early fall, perennial weeds are moving nutrients down into roots and rhizomes to prepare for winter. This period is when they are most vulnerable to herbicide translocation to the roots and better control is possible. Here’s the level of weed control the year after pre-harvest glyphosate for several perennial weed species:
Not only is the control better than in-crop choices, but it is also much more economical. If a Roundup Ready canola variety has been grown, a pre-harvest application will assist in some dry down of green weeds and offer perennial weed control, but it will not dry down the crop. Apply when the crop has 30% or less moisture content. At this stage, the pods are green to yellow and most seeds have turned from green to yellow or brown. Wait three full days (72 hours) after application before swathing to allow thorough translocation of the herbicide to ensure extended long-term weed control. Do not use pre-harvest glyphosate on canola seed crops.
Direct questions regarding this overall report
to John Mayko, Agronomic Research & Extension
Manager with the Canola Council of Canada at 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 Vanthuyne, Agronomist,
Eastern Saskatchewan,
vanthuyd@canola-council.org,
306-782-7799
David Blais, Agronomist, Western
Saskatchewan,
blaisd@canola-council.org,
306-895-2122
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
Alberta,
moiseyd@canola-council.org,
780-645-3624
Christine Mardell, Agronomist,
Peace River Region,
mardellc@canola-council.org,
780-518-1513
Nancy Muchka-Dahl, Agronomist,
Southern Alberta,
muchkan@canola-council.org,,
403-625-3406
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 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; 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.
