Canola Watch Reports

2007 Canola Watch Reports

#12 Western Canada – July 18, 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 has been enhanced by the recent heat. Earlier seeded crops in Manitoba, Saskatchewan and southern Alberta are into full pod and starting to mature, whereas crops in other areas that were seeded late are at bolting to early flower. Hot weather in Alberta and much of Saskatchewan helped to advance the crop, but parts of central and northern Saskatchewan and Alberta are still behind last year in terms of average crop stage. Localized hail has been reported in many areas ranging from pea sized to grapefruit sized. Crops that are damaged at the late bloom and pod stage are unlikely to recover from moderate to severe damage, but crops with a significant amount of bloom may still be able to recover somewhat from light to moderate damage, although maturity will likely be 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/crprpt070716.asp

Good soil moisture conditions remain in many areas, but the recent heat has begun to stress the crops, especially in southwestern Saskatchewan and southern Alberta. As well, many areas in west-central Saskatchewan including Meota and Unity and east-central Alberta including Vegreville, Killam and Paradise Valley 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

There have been concerns of flower blast due to the heat from the past week. High humidity and good soil moisture have helped to minimize the damage, but in areas with depleted surface moisture, damage is increasing. 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

The continuing 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

Diamondback moth larvae continue to be reported in many areas, but numbers remain low at this point in most cases. Growers should be on the alert for damage from the next generation of 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

Grasshoppers continue to be reported in parts of north-central Alberta near the North Saskatchewan River and in many parts of 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 continues across the prairies, with high moth numbers reported in some areas. Areas that have reported high bertha armyworm moth counts include southwestern and central MB and central SK. 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. 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/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

The moth numbers represented in the above maps are cumulative, in that 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.

Heavy root maggot populations continue to be 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 is wrapping up in most areas due to the advancing crop stage. However, later crops that have recently begun to bloom may still be at risk, especially in areas with good soil moisture and relatively dense crop canopies. However, with changing weather conditions, 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. Refer to the publication called the Canola Disease Identification and Sclerotinia Risk Assessment Card which is designed 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. For more information on canola bloom stage identification check the following link: http://www.canola-council.org/sclerotiniachemical.aspx

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.

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.

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.