Canola Watch
2006 Canola Watch Reports
Canola Watch Report No. 15 Western Canada – August 2, 2006
In this issue:
(click the bookmark links below to move to specific sections of this report)
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 be ahead of normal in all regions due to hot and dry weather of this past season. However, the rate of development has slowed in much of central and northern Alberta due to recent cooling temperatures. The majority of the crop in well into podding with only late seeded fields still in flower. Swathing of early seeded crops continues in the eastern and Interlake regions of Manitoba, southwestern Saskatchewan and southeastern Alberta. Most other areas do not anticipate general swathing to commence for another week to three weeks. Soil moisture conditions continue to remain dry in many areas, but widespread rains were received across most of central and northern Alberta including the Peace. Parts of central and northern Saskatchewan and central Manitoba received showers ranging from 5-50 mm.
For current maps of moisture conditions from PFRA for western Canada, check the following links for precipitation from September 1 to July 30 and April 1 to July 30 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
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 allows 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
Spraying for bertha armyworm larvae is occurring in areas with high moth trap numbers identified earlier throughout western Canada. These areas include areas of northwest Manitoba near Swan River, Roblin and Russell and central Manitoba near Somerset, in Saskatchewan near Lemberg, Govan, Biggar, North Battleford, Rosthern, Birch Hills, Tisdale, Preeceville and Kamsack and in Alberta near Milo, Vulcan, Rockyford, Drumheller, Wainwright, Paradise Valley and Vermilion. High numbers (up to 10-15/ft2) have been found in some fields, but numbers and larvae stage vary widely from field to field.
In some areas, spraying for berthas has occurred but apparent
poor control has been reported. The lack of control may be due
to poor application (low water volumes or poor canopy penetration), very high
numbers or poor timing. Remember that most insecticides will not achieve 100%
control. In areas with very high numbers (10-15 ft2 or more), if one achieves
80% control, there still would remain 2-3 /ft2. Also, the moths laid their eggs
over a period of time, therefore the larvae hatch over a similar period of time.
Therefore, there may be more larvae emerging at later stages that were missed
by the insecticide spray. Timing of application is also critical. It is important
to ensure that the larvae are up on the middle to upper parts of the plant and
feeding on the pods. If the larvae are still feeding on leaf material in the
lower canopy or the leaf litter on the ground, there will be poorer control.
Avoid spraying during high temperatures (above 25 degrees C), as the larvae are
likely to be in the lower levels of the canopy. Also, use rates appropriate to
the stage of the larvae. Most insecticides recommend a range of rates. Use higher
rates when faced with high populations and/or larger stages.
Due to the widespread bertha outbreak, availability and access to custom aerial
applicators is at a premium. Growers must ensure that their crops and insects are at the proper stage
before spraying. Spraying just because the plane is in the area is likely to achieve poor results.
Although the use of high clearance ground sprayers will cause some losses from wheel tracking, timely
and effective insecticide application will offset yield losses when compared to a poorly timed or
staged aerial application. Ground sprayers will also allow for the use of higher water volumes and
pressures that may enhance the effectiveness of the insecticide.
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
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
Lygus bugs (ranging from 5-14 per sweep) have been reported in southern Alberta near High River and Vulcan and the Peace near Spirit River and Wanham, with spraying occurring in the Peace.
Diamondback moth larvae were reported near North Battleford, SK and near Peace River, AB. Although populations appear to be below threshold levels at this point, frequent scouting should continue.
Flea beetles were reported in southwestern Manitoba near Virden. Although damage is likely to be low at this stage of the crop, monitoring at this stage will identify areas at potential risk at emergence next spring.
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 continues to cause purpling and premature plant colour change (see photo below) in many canola fields, especially in the upper parts of the canopy exposed to the sun.
Example of purpling and premature ripening
(photo courtesy Brian DeKock, Dow AgroSciences
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. Refer to last week's Canola Watch report for further comments on pre-harvest applications:
http://www.canola-council.org/Canola-Watch-Report-14.html
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 John Mayko, Agronomic Research & Extension Manager, maykoj@canola-council.org ph/fax: 780-764-2593
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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