Canola Watch Reports

2007 Canola Watch Reports

#13 Western Canada – July 25, 2007

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 spurred on by the persistent heat. Earlier seeded crops in Manitoba, Saskatchewan and southern Alberta are fully podded and starting to mature, whereas crops in other areas that were seeded late are at early to full flower.

An overview of prairie vegetation conditions is available at (use the “start the prairies application” button on the left hand side): http://www26.statcan.ca/ccap/ccaphome_en.jsp

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/crprpt070723.asp

Concerns about heat stress are common across western Canada. There are many reports of flower blasting (orange or white flower petals) due to the heat. Bloom periods have been shortened. Dryland crops in southern Alberta are very short with few pods. As well, reports of pod shrinking (pods looking like they are shrink-wrapped around the seed) are occurring in many areas. High humidity and good soil moisture have helped to minimize the damage in some areas, but in areas with depleted surface moisture, damage is severe. 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 degrees Celsius 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. However, hail, lack of available sulphur, late herbicide applications or feeding from insects such as lygus bugs, bertha armyworm and diamondback moth larvae may also result in gaps on the main stem. Further information is available in the following Canol@Fact:
http://www.canola-council.org/PDF/Canola%20Fact%20Sheet%20-%20Missing%20Pods.pdf

Soil moisture conditions remain favorable in many areas of Manitoba, northern and eastern Saskatchewan and west-central Alberta between Calgary and Wetaskiwin but topsoil moisture is very dry in many areas of southern Saskatchewan and Alberta as well as parts of west-central Saskatchewan and east-central Alberta. Many areas would welcome a rain to replenish topsoil moisture and provide some respite from the continuing heat. For current maps of moisture conditions from PFRA for western Canada, check the following links for precipitation since September 1 and April 1 respectively:
http://www.agr.gc.ca/pfra/drought/prpay07_e.htm
http://www.agr.gc.ca/pfra/drought/prpgs07_e.htm

Additional moisture information for Alberta is available from Alberta Environment at: http://www3.gov.ab.ca/env/water/WS/data/precipmaps/weekly.pdf

There have been a few reports from Saskatchewan regarding aster yellows disease that may have been mistaken for sulphur deficiencies or herbicide damage. Aster yellows is caused by a phytoplasma, a plant pathogenic micro-organism. The phytoplasma inhabits the phloem (nutrient-carrying vessels) of infected plants and is carried from plant to plant by sap-sucking leafhoppers. Now is the time of year that aster yellows symptoms will start showing up in the field and looking more conspicuous because infected plants tend to stand taller and and are discoloured compared to non-infected plants. There aren’t any preventative or control measures that producers can do to manage or prevent aster yellows in canola. Following is the link to SAF’s factsheet on aster yellows: http://www.agr.gov.sk.ca/docs/production/asteryellows01.asp

Diamondback moth larvae continue to be reported in many areas, but numbers remain below thresholds at this point in most cases. Growers should be on the alert for damage from the larvae that will begin feeding on the leaves, and then move up onto the pods at the later crop stages. For more information on diamondback larvae, refer to the following link: http://www.canola-council.org/Diamondbackmoth.aspx

Bertha armyworm larvae have begun to hatch and develop in many areas including western and central MB and central SK. Growers in all areas affected by bertha armyworms last year, as well as areas reporting bertha armyworm moth activity this year should be on the lookout for their emergence and development. Control for bertha armyworm occurs at the larval stage, usually when the larvae begin feeding on the pods. Spraying for moths is not an effective control method and will likely do more harm in terms of destroying any beneficial insects in the crop. Spraying should be delayed until the larvae have reached the third or fourth in-star stage, as it is the last two in-stars stages that cause the most damage. As well, delaying spraying to the later stages will allow for the majority of the bertha eggs to hatch, thereby reducing the need for a subsequent insecticide application. For further information regarding bertha armyworm, please refer to the following link: http://www.directfocus.com/canolamanual/chapter10b.html#ch10b_sec6a

For more information on bertha armyworm counts in Manitoba, please refer to the following MAFRI link:
http://www.gov.mb.ca/agriculture/crops/insects/bertha/index.html
For more information on bertha armyworm counts in Saskatchewan, please refer to the following SAFRR link:
http://www.agr.gov.sk.ca/docs/production/images/berthaArmywormMap20070711.pdf
For more information on bertha armyworm counts in Alberta, please refer to the following link:
http://www1.agric.gov.ab.ca/$Department/deptdocs.nsf/all/prm11487/$FILE/7-17-7baw.png

Moth numbers in the maps are cumulative - the moth numbers reported in each reporting period are added up and the total to date is reported. Trap counts are still being collected and added to the maps, so for areas still showing low risk, it is important to keep checking for updates because those numbers may still increase.
Remember these maps are an indication of risk in a region. Field scouting is still required to ensure economic damage does not occur in individual fields.

Timing of insecticide application for bertha control is 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. 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. Also at the latest stage, ensure that the larvae are actively feeding. Larvae at the latest stage may be inactive on the ground as they prepare to pupate.

Before considering any further applications of fungicides or insecticides, remember to allow for the required pre-harvest interval for any products being considered. Growers need to ensure that the appropriate preharvest interval is followed to eliminate chances of excess residues appearing in the harvested seed, 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
Early seeded crops in parts of southern Alberta and Saskatchewan are nearing maturity. 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 link for more information on swathing in hot, dry weather:
http://www.canola-council.org/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. To learn more about proper harvest field assessment, refer to the revised Canola Council publication "Canola Time of Swathing Guide" or the following link: http://www.canola-council.org/pub_swathing.html

At this time of the year, growers are preparing 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

Direct questions regarding this report to John Mayko, Senior Agronomy Specialist, Parkland West (West Central AB), 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 agronomists or provincial oilseed specialists:

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.