In this issue:
(click the bookmarked links below to move to specific sections of this report)
Cool weather delays crop development
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 in most areas was delayed by the cool weather of the past week. Swathing continues slowly on early seeded crops in Manitoba, Saskatchewan and southern areas of Alberta. Swathing in most other areas is not anticipated to start for at least another week to 10 days. There are also some late seeded fields that are at the end of flowering. Overall, established canola crops throughout western Canada appear to be in good to excellent condition, except for the areas that experienced extended flooding this past spring. However, high temperatures in July and early August have caused some pod abortion in some areas and have likely reduced the amount of pod fill. Normally, these lower levels of soil moisture are not a problem, but the generally shallow root systems of many of this year’s canola have predisposed them to moisture stress without regular rain.
For current maps of moisture conditions from PFRA for western Canada, check the following link: http://www.agr.gc.ca/pfra/drought/prpay05_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 and soil moisture map from Saskatchewan Agriculture, Food & Rural Revitalization is available at:
http://www.agr.gov.sk.ca/docs/reports/crop_report/crprpt050815.pdf
Additional moisture information for Alberta is available from Alberta Environment at:
http://www3.gov.ab.ca/env/water/ws/data/precipmaps/precipmaps.html
Frost was reported this past week in many areas including northern and northwestern Saskatchewan (Preeceville, Shellbrook, Prince Albert, Meadow Lake, Makwa, Glaslyn, Cutknife, Wilkie), east central Alberta (Sedgewick, Hardisty, Bonnyville) and the north Peace (Lacrete, High Level). Although the frost damage was light in most of these areas, there may be low lying areas that received more significant damage. Growers need to be patient in accurately determining the level of damage after a frost. To determine when to swath after a frost, check the extent of damage 2-3 days after the frost. Frost damage will be evident on the outside of the pods, which will often show a white, speckled appearance (caused by ruptured cell walls leaking fluid). Immature and watery seeds will start to leak their inner fluid, and begin to shrivel. The outside of the seeds will begin to turn dark green, instead of a light-medium green. If the majority of the seeds remain turgid, delay swathing to allow for further seed maturity. If the pods are severely damaged and are beginning to desiccate, swath during periods of dew or high humidity to reduce the amount of pod shelling and pod drop. For a more detailed discussion on the effects of frost on various crops, refer to the following SAFRR link: http://www.agr.gov.sk.ca/docs/crops/frostdamage.pdf
Insect activity of lygus, cabbage seedpod weevil and diamondback larvae continue at low levels in most areas at this time. Bertha armyworm activity continues to require spraying in the central Peace near Eaglesham and Wanham, AB, east-central Alberta near Vermilion, Lloydminster and Wainwright, and northwest Manitoba in the Swan River Valley and areas around Roblin. Other areas with increased bertha armyworm activity include Strasbourg, Raymore, Lanigan, Earl Grey and Laird, SK. Some fields in the central Peace may need to be resprayed due to the high populations and cooler temperatures. Much of the activity in east-central Alberta appears to be on later seeded canola fields. Growers need to continue monitoring for all these pests right through to swathing, as numbers can suddenly increase and cause substantial yield losses on developing and maturing pods.
If numbers are exceeding threshold levels and an insecticide treatment is needed, be sure to choose a registered insecticide with an appropriate pre-harvest interval. This is especially true for canola that needs more than one insecticide application and/or is close to reaching maturity. Remember that for determining appropriate preharvest intervals, harvest is defined as the point at which the plant is cut, which means swathing or straight cutting.
For more information on late season scouting techniques refer to the following press release: http://www.canola-council.org/about-us/media-news/media-releases/media-jun2005.shtml
For current diamondback moth and bertha armyworm survey updates, refer to the following link:
http://ncrxeis4.agr.gc.ca/ppmnMaps/
For more information on the bertha armyworm, including accurate identification and thresholds for insecticide control, refer to the following links:
http://www.canola-council.org/bertha.aspx
http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/prm2521
As the canola crop completes pod development, be vigilant in the frequency and intensity of field scouting. Watch for abnormal areas that have wilted, or for prematurely ripening plants within canola stands that are otherwise healthy. These areas may be indicators of diseases such as fusarium wilt, sclerotinia, blackleg and clubroot that restrict water and nutrient uptake by plants. Also scout for alternaria black spot, as it can affect harvest management decisions. It continues to show up in some areas this year, including western regions of Manitoba and eastern Saskatchewan. Crops with black spot lesions covering a large proportion of pod surfaces are at increased risk for shattering and are poor candidates for delayed swathing or straight combining.
When scouting fields, accurately identify what is causing the damage and properly document the information for future reference and decision making. Scout for insects, 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 the fertility plan worked and to help make important fertility decisions in the upcoming season.
For more information on Alternaria black spot refer to the following link:
http://www.canola-council.org/alternariasymptoms.aspx
New strains of blackleg have been found in Manitoba and eastern Saskatchewan in recent years. Efforts are being made to determine the occurrence and prevalence of these new strains. Growers who notice elevated blackleg levels in MR and R rated varieties and who would like to participate in the survey should collect samples and have them tested to determine what strain is present. Interested growers should e-mail Dr. Dilantha Fernando at d_fernando@umanitoba.ca for sampling and shipping instructions.
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.
Last year, time of swathing recommendations were changed to reflect research results obtained after several years of Canola Council 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. 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.shtml
There are many questions regarding swathing timing for canola fields with variable growth caused by uneven emergence or stress from early season flooding. Growers should assess where the majority of their yield will come from and manage accordingly. If the majority of the field is still green, swathing should start when adequate seed colour change occurs in these areas. In fields where green and mature areas are more equal in size, be sure that seeds in the green areas are firm and no longer translucent. Swathing should be delayed as long as possible to allow for seed colour change to start in the green areas. To minimize losses in the ripe areas, growers should consider swathing in the evening or early morning.
Many growers are considering desiccating these variable fields and straight combining them. Desiccation has the same effect as swathing under conditions of rapid dry down. Desiccation needs to be delayed until there is significant seed colour change in the green areas to avoid premature dry down of the crop and minimize yield losses and green seed.
There are some questions regarding the use of Reglone (diquat) or glyphosate to speed up and even out crop development. Reglone is a contact herbicide and is much faster acting than glyphosate, but it does not translocate to the roots of perennial weeds. Remember that application of either product results in eventual killing of the plant. Application of either product too early will cause similar problems to swathing too early, with the additional possibility of increased herbicide residues in the crop. Be diligent in following label directions for product application timing, rates and water volumes.
With swath stage 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 control options. 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.
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.
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.
Send questions regarding this report to John Mayko, Agronomic Research & Extension Manager with the Canola Council of Canada at maykoj@canola-council.org ph/fax: 780-764-2593.
Direct specific questions regarding regional issues to 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 & Rural Initiatives,
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
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@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.
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