Canola Watch
2006 Canola Watch Reports
Canola Watch Report No. 14 Western Canada – July 26, 2006
In this issue:
(click the bookmark links below to move to specific sections of this report)
Some canola swathing already underway
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 continues to advance rapidly due to above normal temperatures
across most regions. The majority of the crop has finished flowering with the exception of late
seeded crops, and continues to be a function of seeding date in most areas. Swathing has started
in the eastern part of Manitoba and south western Saskatchewan. Most other areas do not anticipate
general swathing to commence for another week to three weeks. Soil moisture conditions continue to
deteriorate in most areas due to the lack of general rain and above normal temperatures. Only spotty
thundershowers were received in most areas again this past week with some localized amounts of up to
1 inch. Crops in the north Peace, and many parts of Saskatchewan still look good at this point, but
most other areas are in need of rain soon to salvage decent yields. In most areas earlier seeded
crops appear to have withstood the July heat better than later seeded crops.
For current maps of moisture conditions from PFRA for western Canada, check the following links for
precipitation from September 1 to July 24 and April 1 to July 24 respectively:
http://www.agr.gc.ca/pfra/drought/prpay06_e.htm
http://www.agr.gc.ca/pfra/drought/prpgs06_e.htm
http://www.agr.gc.ca/pfra/drought/pa_e.htm
The latest crop report from Manitoba Agriculture, Food and Rural Initiatives is available at:
http://web2.gov.mb.ca/agriculture/mwcr/
The latest crop report from Saskatchewan Agriculture, Food & Rural Revitalization is available at:
http://www.agr.gov.sk.ca/docs/reports/crop_report/crprpt060723.pdf
Additional moisture information for Alberta is available from Alberta Environment at:
http://www3.gov.ab.ca/env/water/WS/data/precipmaps/weekly.pdf
Heat stress (plants wilting and sometimes taking on a bluish
grey hue), blossom blasting (flower or pod abortion), a shortened bloom
period and formation of short underdeveloped pods continue to be reported
across western Canada. The most likely cause in these areas is drought and/or heat stress, but it
is important to scout the affected areas to see if there may be some other underlying
contributing factors such as root damage from root maggots or clubroot, or stem damage
from blackleg. For more information on heat stress check the following link:
http://www.canola-council.org/temp_frost_hail.aspx
Hail damage from isolated scattered thundershowers was reported
in some areas of Alberta. Potential canola yield losses will depend on stage of crop and the severity
of the damage. Hail damage can also allow points of entry for diseases such as sclerotinia stem rot,
alternaria black spot and blackleg to infect canola plants. Further information is available at the
following link: http://www.canola-council.org/stress_hail.aspx.
Remember to keep scouting fields on a regular basis to detect
problems early. Consider establishing a scouting tramline by driving an ATV in an 'X' or 'W' pattern
in the field to establish pathways for crop scouting. This will allow for easier scouting at later crop
stages. Also, for more information and tips on late season scouting for both diseases and insects, view
the following Canola Advantage press release at
http://www.canola-council.org/media_jun1906.html.
Bertha armyworm moth numbers have dropped in traps placed in canola
fields throughout western Canada. Cumulative counts have exceeded 1000 in areas of northwest Manitoba in the
rural municipality of Swan River, in Saskatchewan near Lemberg, Govan, Biggar, North Battleford, Birch Hills
and Tisdale and in Alberta near Milo and Vulcan. As well increasing numbers were noted in eastern Alberta
near Vermilion and Wainwright. Spraying for larvae is taking place in the Swan River valley in MB, and many
other areas are reporting emerging larvae so growers in all traditional canola growing areas should be on the
alert for this pest and watch for further information.
For more information on the bertha armyworm, refer to the following link:
http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/prm2521
For interpreting bertha armyworm trap numbers, refer to the following link:
http://www.gov.mb.ca/agriculture/news/insect/bertha/interpret.html
Refer to the following links for the current bertha armyworm count maps:
http://www.agr.gov.sk.ca/docs/crops/integrated_pest_management/insects/Berthamap20060719.pdf (SK)
http://ncrxeis4.agr.gc.ca/ppmnMaps/20060723_bertha_armyworm_ab.pdf (AB-BC Peace)
http://ncrxeis4.agr.gc.ca/ppmnMaps/20060723_bertha_armyworm_mb.pdf (MB)
http://ncrxeis4.agr.gc.ca/ppmnMaps/20060723_bertha_armyworm_pr.pdf (Overall Prairies)
Proper identification of bertha armyworm larvae is important as they
can be confused with other larvae especially in their early development stages. For more information
regarding bertha armyworm identification, please refer to the Canola Scouting and Sweep Net Insect ID
Card and the following links:
http://www.canola-council.org/berthaidentification.aspx
http://www.canola-council.org/PDF/sweepcard_pgs_04.pdf#page=1
Scouting for bertha armyworm larvae should occur in the cool parts of early morning or late evening when they are actively feeding. In crops with good vegetative growth remaining on the plant, the larvae will be found feeding on leaves in the lower part of the crop canopy. In crops where much of the leaf matter has fallen off, search for larvae under leaf litter on the ground, especially if scouting during hotter parts of the day. An insecticide application will be needed if numbers exceed economic thresholds and larvae move up the plant and begin feeding on pods.
Although yields may have been impacted negatively by the heat and drought in many areas, use appropriate thresholds to determine whether control of bertha armyworm larvae is warranted (Table 1). The larvae will eat plant material in proportion to their populations and crops with a lower yield potential will suffer similar yield loss (in terms of bu/ac) to a higher yielding crop.
Table 1. Economic thresholds for bertha armyworm on Argentine canola. For example, assuming a crop price of $7.00 per bushel and a spraying cost of $10.00 per acre, the table indicates an economic threshold of 25 bertha armyworm larvae per square metre. Spraying would not be economical if larvae counts are less than 25 per square metre.
| Expected Seed Value - $/bushel |
Spraying
Cost - $/acre |
6 |
7 |
8 |
9 |
10 |
11 |
12 |
| Number of Larvae/metre² |
| 7 |
20 |
17 |
15 |
13 |
12 |
11 |
10 |
| 8 |
23 |
20 |
17 |
15 |
14 |
13 |
11 |
| 9 |
26 |
22 |
19 |
17 |
16 |
14 |
13 |
| 10 |
29 |
25 |
22 |
19 |
17 |
16 |
14 |
| 11 |
32 |
27 |
24 |
21 |
19 |
17 |
16 |
| 12 |
34 |
30 |
26 |
23 |
21 |
19 |
17 |
For more information on the proper timing of bertha armyworm control, refer to the following MAFRI link:
http://www.gov.mb.ca/agriculture/news/insect/miu06_07_17.html
Refer to the following link for more information on monitoring and control of bertha armyworm:
http://www.canola-council.org/berthamonitoring.aspx
If a pesticide application is made to control any pests in-crop, ensure that appropriate pre-harvest intervals are followed. Pre-harvest interval refers to the time from application of product until the point at which the crop is cut (swathed or straight cut). Ensure that the appropriate preharvest interval is followed to eliminate chances of excess residues appearing in the resulting crop, and damaging markets. Refer to the following links for information on pre-harvest intervals for some common pesticides and description of the importance of following pre-harvest intervals:
http://www.canola-council.org/pre_harvest.html
http://www.canola-council.org/general_pesticide_link.html
For more information on registered insecticides for bertha armyworm control refer to the following links:
http://www.gov.mb.ca/agriculture/crops/cropproduction/gaa01d01.html
http://www.agr.gov.sk.ca/Docs/crops/cropguide00.asp
At this time of the year, growers are beginning to prepare their bins for storage of the upcoming harvest. It is important to note that malathion and other similar insecticides should not be used to treat grain bins for insects prior to storing canola. Although this practice is common for cereal crops, oilseed crops like canola can absorb the malathion from the bin surfaces and the resulting residues have been found in crop delivered to elevators. Therefore, DO NOT use malathion to treat bins destined to store canola from the upcoming harvest. Refer to the following link for further information:
http://www.canola-council.org/pesticide_link2.html
The recent hot and dry weather has caused purpling and premature plant colour change in many canola fields. This is a relatively normal response to stress and growers need to ensure that seed colour change is occurring when assessing the proper time to swath. The colour of mature plants and pods will vary among varieties as they mature. Some will appear ripe on the outside before the seeds are mature, so avoid using plant colour as a gauge to proper timing. Open up pods on the main stem and look at the colour of the seeds to accurately assess swathing timing. Refer to the following press release for more information on swathing in hot, dry weather:
http://www.canola-council.org/about-us/media-news/media-releases/media-jul2606.html
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. It widens the "swathing days" window for all growers, including those with large canola acreages. When conditions are hot and dry, avoid swathing. Swath during cool evening hours, at night or early in the morning to allow plants to dry down at a slower rate. This reduces the chance of green seed.
When assessing seed colour, also check seed firmness. Under cool conditions, seeds near the top of the plant may continue to fill and become firm before the lower seeds begin to turn colour. Also, be conscious of disease-infected or hail-damaged fields and do not let the premature ripening of the diseased or damaged plants influence the time of swathing. Realize that the bulk of the yield is likely still coming from the healthy plants. A better strategy than swathing early to capture more yield is to swath during dew periods to prevent shattering of the damaged plants. To learn more about proper field assessment, refer to the revised Canola Council publication "Canola Time of Swathing Guide" or visit the Canola Council website:
http://www.canola-council.org/pub_swathing.html
With swathing approaching, consider a valuable weed control tool for next year's crop--pre-harvest glyphosate. It's the most consistent and effective treatment for many perennial weeds, providing an effective and economical alternative to in-crop applications. In early fall, perennial weeds are moving nutrients down into roots and rhizomes to prepare for winter. This is when they are most vulnerable to herbicide translocation to the roots and better control is possible.
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 seed 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 crops grown for seed.
If applying any preharvest chemicals prior to harvest with ground rig sprayers, the use of crop dividers can reduce the amount of crop loss due to trampling and shattering. In addition, traveling back and forth in the direction of prevailing crop lean will further reduce losses.
There are a number of growers considering straight cutting their canola
this year. To be successful, consider the following factors:
Crop Canopy - the crop
should be well knitted and slightly lodged to reduce the chance of pod shelling and pod drop. Remember that
pod integrity (including petiole strength which influences pod drop) can be affected by frost and drought.
Disease - the crop should be relatively free from diseases including blackleg, fusarium wilt, sclerotinia
and alternaria. These diseases can cause premature ripening, which can in turn cause pod shattering.
Hail - Crops affected by hail are poor candidates for straight cutting due to the probability of greater
disease infection through damaged tissue and reduced pod integrity from physical damage. Also, any late season hail
often causes greater levels of damage to standing crops than swathed crops.
Direct questions regarding this report to David Blais, Agronomist, western Saskatchewan
blaisd@canola-council.org ph/fax: 306-895-2122.
Direct specific questions regarding regional issues to one of the following Canola Council of Canada agronomists or provincial oilseed specialists:
Derwyn Hammond, Agronomist, Manitoba,
hammondd@canola-council.org, 204-729-9011
Arvel Lawson, Manitoba Agriculture, Food & Rural Initiatives,
alawson@gov.mb.ca, 204-745-0340
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
Penny Pearse/Scott Hartley, Saskatchewan Agriculture, Food & Rural Revitalization,
ppearse@agr.gov.sk.ca / shartley@agr.gov.sk.ca , 306-787-4671 / 306-787-4669
Doug Moisey, Agronomist, Central Alberta,
moiseyd@canola-council.org, 780-645-3624
Jackie Heck, Agronomist, Peace River Region,
heckj@canola-council.org, 780-853-5261
Matthew Stanford, Agronomist, Southern Alberta,
stanfordm@canola-council.org, 403-758-6660
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@gov.bc.ca, 250-784-2559
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; 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.
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