Canola Watch Reports

2007 Canola Watch Reports

#11 Western Canada – July 11, 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 vary widely. Earlier seeded crops in Manitoba, Saskatchewan and southern Alberta are into full bloom and early podding, whereas crops in other areas seeded in early-mid June are at the rosette to bolting stage. Warm weather last week allowed crops to develop quickly, but parts of central and northern Saskatchewan and Alberta are 1-2 weeks behind last year in terms of average crop stage. Localized hail has been reported in many areas ranging from pea sized to golf ball sized. Remember it will take several days to determine if a crop might recover from hail damage. Crops that have been severely damaged but are able to recover will be significantly delayed.

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/crprpt070709.asp

Good moisture was reported in many areas, especially those that received precipitation over the past two weeks. Warm conditions reduced the area suffering from excess moisture, but other areas such as southern Alberta, southwest Saskatchewan, northern Alberta near Lougheed, Castor and Killam and the Peace near Lacrete and Beaverlodge are getting quite dry and would welcome some rainfall soon. 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

Remember to keep scouting fields on a regular basis to detect crop development 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 with minimal trampling at later crop stages, especially once the crop is blooming. Although counts of some pests are currently declining, second generations will begin to appear soon and continued vigilance is necessary.

Clubroot has been identified in an irrigated field near Bassano, AB. Ron Howard from AB Agriculture and Food initially identified the disease on infected plants and it was later confirmed using the new PCR test. This is the first confirmed report of clubroot in this area and it highlights the need for good equipment sanitation and ongoing scouting. Clubroot is a soil borne disease that mostly moves between fields in soil carried on contaminated equipment.

The hot weather forecast for many areas this week may identify plants within a field that are wilting and ripening prematurely. These wilted plants should be dug up to determine the cause of the wilting, which could be caused by clubroot, or other factors such as sclerotinia or root maggots. For more information on identifying clubroot, refer to the following link: http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex8593

Spraying for cabbage seedpod weevils has just about wrapped up in southwestern Saskatchewan and throughout southern Alberta south of Hwy. 1. Sweep counts in many later fields have been declining and careful scouting is needed to ensure treatment is worthwhile. Remember that the second generation of cabbage seedpod weevil will emerge later in the season so scouting in affected regions needs to be continued. For more tips on scouting and controlling cabbage seedpod weevil, refer to the following links: http://www1.agric.gov.ab.ca/$Department/deptdocs.nsf/all/agdex2538
http://www.directfocus.com/canolamanual/chapter10b.html#ch10b_sec7

Diamondback moth larvae continue to be found in fields across central Manitoba, southern and eastern Saskatchewan, and southeastern Alberta, but in most areas they have entered the pupal stage as noted by the presence of cocoons on canola plants. Growers in all areas should be withholding spraying when the larvae are pupating. The pupal stage lasts from five to 15 days depending on environmental conditions, then adult moths of the next generation emerge, begin laying eggs and the cycle repeats, with the eggs hatching in about five or six days. Growers should then be on the alert for damage from this next generation.
Growers should use caution before spraying for diamondbacks at this early stage because spraying is likely to destroy beneficial parasitoids, which help in reducing damage from subsequent generations. For a picture of a parasitic wasp of diamondback, refer to the following link: http://www.canola-council.org/parasiticwaspsid.aspx
For more information on diamondback moth, refer to the following SAFRR link:
http://www.agr.gov.sk.ca/docs/production/Diamond.asp

Grasshoppers continue to be reported in many parts of northern Alberta including the St. Paul and Vermillion areas and the Peace region. Although most damage from grasshoppers usually occurs on cereals and forage grasses, damage to canola can occur if other food sources are not present. Scout carefully to determine whether the species noted are actually pest species and whether damage is occurring to canola. For more information regarding identification of grasshoppers, refer to the following web link from Dr. Dan Johnson at the University of Lethbridge: http://people.uleth.ca/~dan.johnson/htm/dj_gh_guide.htm

Monitoring of bertha armyworm moths is taking place across the prairies, with increasing moth numbers reported in some areas. Areas that have reported high bertha armyworm moth counts include eastern and southwestern MB, southeastern SK, and north-central AB. Moth counts this week are lower in many areas when compared to last week, which would indicate that the peak of the moth flight may have passed in these areas. For further information regarding bertha armyworm, please refer to the following link: http://www.directfocus.com/canolamanual/chapter10b.html#ch10b_sec6a

Prairie wide bertha armyworm moth maps are being developed, and web links for the respective provinces are as follows:

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/berthaArmywormMap20070704.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/baay7w5h.png

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.

Heavy root maggot populations are being reported in many fields in central and northern Alberta and parts of the Peace region. Although there are no effective methods of in-crop control, there are some agronomic practices that can be used to try to reduce damage in future years. For further information on root maggots, refer to the root maggot section in the following link: http://www.directfocus.com/canolamanual/chapter10b.html#ch10b_sec16

Fungicide spraying for sclerotinia control has been reported in most areas. The high levels of soil moisture in many areas combined with warm temperatures and crops at full ground cover, create conditions that are conducive to sclerotinia development. However, with warmer and drier weather in the forecast for many areas, risk levels may change, so producers should carefully consider all of the factors highlighted in the sclerotinia stem rot checklist before making this decision. These factors include how heavy their crop canopy currently is, the amount of moisture received in the two weeks prior to flowering and potential for future rainfall, years since last host crop, disease incidence in the past, and the presence of apothecia in neighboring fields where host crops were grown previously. Target yield, fertility program and expected value of the canola crop are also points to consider.

A publication called the Canola Disease Identification and Sclerotinia Risk Assessment Card is available to assist growers and crop scouts with this decision. It includes the stem rot checklist and pictures to aid in accurately identifying the apothecia of the sclerotinia fungus. A PDF version can be found at http://www.canola-council.org/PDF/canola_plant_disease_risk.pdf#page=1 or contact your local Canola Council Agronomy Specialist.

If a producer’s risk assessment based on checklist results and/or petal testing suggests that spraying may be warranted, splitting fungicide applications may be an option. An initial reduced fungicide application at 20 to 30% bloom will help control early onset of the disease. If conditions become drier, a second application may not be needed. However, if this approach is taken and conditions remain wet and humid, a second application will be needed to maximize the benefits of spraying the fungicide. Producers should assess these factors and consult their local agronomist or chemical representative to determine if a single or a split fungicide application is best for their particular situation.

For growers who have decided to apply a fungicide to control sclerotinia, determining the bloom stage of the crop is important. The optimum stage for a single fungicide application is when the maximum number of flowers is open but little if any petal drop has taken place, usually at or slightly above 30% bloom. Typically at this stage in B. napus canola there is an average of about 20 flowers open on the main stem, with some flowers open on secondary branches but little or no pod formation. Some early seeded fields are past the 50% bloom stage and into pod formation, and are now too advanced for effective fungicide application. For more information on bloom stage identification check the following link: http://www.canola-council.org/sclerotiniachemical.aspx.

Missing pods and blank areas on the stem have been noted in several areas. These gaps usually occur as a result of stress. Although there is no remedial action that can be taken, it is important to try to identify the cause in order to take steps to prevent similar problems in future crops. For more information on possible causes please refer to the following link:
http://www.canola-council.org/PDF/Canola%20Fact%20Sheet%20-%20Missing%20Pods.pdf

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.