Preparing for 2024: Canola disease recap

disease survey set up disease survey set up disease survey set up disease survey set up

There are many excellent meetings and conferences throughout the winter which provide useful updates on the crop disease situation across the Prairies and in specific provinces. Drawing from all of these events, related reports and the provincial crop pathology experts, this blog summarizes the diseases pressures that impacted canola in 2023 and how this can inform what can be done in 2024 to support canola production.

To ensure the disease survey results are interpreted as accurately as possible, keep in mind:

  • Prevalence is the % of fields surveyed that have infection in them.
  • Incidence is the % of plants surveyed within a field that have disease symptoms.
  • Severity is the degree of infection in a plant, often rated with a scale (ex. 0-5 scale for blackleg).
  • For any canola disease to be present, the disease-causing pathogen must have been present (ex. Sclerotinia sclerotiorum), the host plant (ex. canola) must have been present and the environment must have been conducive to the disease (ex. warm and humid). These three components are often referred to as the disease triangle.
  • Proper scouting methods (including the random selection of at least 100 plants from a “W” pattern in a field) are essential to the collection of good quality data.

The complete plant disease situation from 2023, will be posted in the Canadian Journal of Plant Pathology once finalized.

Apply this research on your farm

  1. Assess disease risks using these maps and data along with your notes on your 2023 fields (and plan for record-keeping in 2024).
  2. Use CCC resources to better understand disease cycles and which strategies are effective to address them.
  3. Make a disease management plan with your agronomist which includes scouting and reference guides.
  4. Sign up to support provincial disease survey efforts.
  5. Subscribe to Canola Watch and Prairie Crop Disease Monitoring Network (PCDMN) for updates this growing season.

Manitoba survey results

A total of 129 canola crops were surveyed by Manitoba Agriculture and Agriculture and Agri-Food Canada Brandon staff between August 2-30, 2023 in the major canola production regions of Manitoba. Regions included Southwest (46), Central (40), Northwest (29), Eastern/ Interlake (14). The majority of the crops were surveyed before while canola is ripening, before swathing. To understand the environmental conditions throughout the growing season, see the Manitoba seasonal summary.

A summary of the disease survey dataset is provided in the table and a comparison of canola disease prevalence over the past five years is provided in the graph. Regional disease survey results and detailed results from the last five years are provided in the Manitoba Canola Disease Survey for 2023 report.

Further details on this survey (such as foot rot was not observed in the survey) are available in the WFPM 2023 oilseed disease report. This report also explains that there was one new symptomatic case of clubroot in the 129 canola fields surveyed, which does not require changes to the clubroot distribution map, so the previous clubroot distribution map for Manitoba is still applicable. In addition, three positive cases were documented outside of the survey from submitted soil samples. Soil samples from 40 additional fields have been collected and are currently being processed for clubroot DNA.

Manitoba Canola Disease Survey 2023
Manitoba Canola Disease Survey data: Average incidence in infected crops (2023): SSR – 5%; BSC – 12%; VS – 11%. Note – Aster Yellows was seen in 21% of the 129 crops surveyed (which is the highest prevalence since 2012). Source credit: David Kaminski, Field Crop Pathologist with Manitoba Agriculture
Canola DiseasePrevalenceIncidence*Severity
Alternaria pod spot9%0.1
Aster yellows21%
Blackleg (basal)78%10%1.1
Blackleg (stem)29%0.9%
Clubroot<1%
Sclerotinia stem rot13%5%0.2
Verticillium stripe29%3%
*This average incidence is based on all crops surveyed on a provincial basis (not the average incidence in infected crops, which is always greater). Source: the Manitoba Canola Disease Survey for 2023 report.

Actions to take in Manitoba in 2024

  • Learn from the Canola Council of Canada’s disease cycle infographics and utilize suggestions from disease management guides.
  • Get involved. Contact David Kaminski, Field Crop Pathologist with Manitoba Agriculture out of Carman, Manitoba if you are willing to participate in the 2024 survey (again or for the first time) or have questions about the disease survey process or results.
  • Submit free canola samples to the PSI lab through the #GetTested program for clubroot, blackleg presence and race identification and verticillium stripe testing, if you are a member of the Manitoba Canola Growers qualify. Additional testing offered at a fee include glyphosate resistance kochia and Amarnath species identification.

Saskatchewan disease survey

The results of the 2023 Saskatchewan canola disease survey, which included 218 surveyed fields located across the major canola growing regions of Saskatchewan. Verticillium stripe was confirmed (by PCR) in 23 fields. No new visible clubroot symptoms were reported by the Saskatchewan clubroot monitoring program in 2023.

As noted in the WFPM 2023 oilseed disease report, symptoms of powdery mildew were observed in 13 of the surveyed fields. Symptoms suggesting downy mildew, white rust, and bacterial pod spot were not found in any of the surveyed fields assessed. For regional disease survey results, see the WFPM 2023 oilseed disease report.

In addition to the regular disease survey, the Saskatchewan Ministry of Agriculture initiated a verticillium-specific survey in 2023, targeting 100 fields across Saskatchewan to assess the prevalence and incidence of the disease and help evaluate the risk this disease poses to canola production in Saskatchewan. Initial observations suggested that verticillium stripe is no longer a rare disease in Saskatchewan, as depicted in the Ministry of Agriculture’s 2023 Verticillium Stripe Distribution in Saskatchewan map.

Canola DiseasePrevalenceIncidence*Severity*
Alternaria pod spot48%0.1
Aster yellows65%2%
Blackleg (basal)72%12%0.2
Blackleg (stem)32%3%
Foot rot3%
Sclerotinia stem rot30%4%0.1
*Average percentage incidence of disease and average severity of disease is based of all canola crops in 2023 Saskatchewan Canola Disease Survey (including both those with and those without the given disease). Source: WFPM 2023 oilseed disease report.
2023 sclerotinia in canola incidence map of Saskatchewan
The Saskatchewan Ministry of Agriculture’s 2023 sclerotinia stem rot incidence map (released November 7, 2023)
SK clubroot survey results map (Jan 2024)
The Saskatchewan Ministry of Agriculture’s 2008-2023 clubroot distribution map (released January 8, 2024).
2023 Verticillium Stripe Distribution in Saskatchewan
The Saskatchewan Ministry of Agriculture‘s 2023 Verticillium Stripe Distribution in Saskatchewan map.

Actions to take in Saskatchewan in 2024

Alberta

Two disease survey efforts take place in Alberta, which are provided in the WFPM 2023 oilseed disease report. The Alberta survey took place between August 3 and October 6, 2023 and included 380 canola fields. The north-central Alberta survey included 50 canola fields. Preliminary results from these surveys are presented in the table. As with all other reports, the complete plant disease situation from 2023, will be posted in the Canadian Journal of Plant Pathology once finalized.

To recall the environmental conditions throughout the growing season, check out the Alberta seasonal summary report.

Alberta surveyAlberta north-central survey
Canola diseaseNo. of fields ratedPrevalenceIncidenceSeverityNo. of fields ratedIncidence
Blackleg35392%26.4%0.55010%
Clubroot6116.2%*0.6%0.5503.5%
Root rotno datano datano data5011.2%
Sclerotinia stem rot34621.4%1.2%no data5011.0%
Verticillium stripe35618.2%0.9%no data50no data
*There were 141 additional fields were identified with clubroot via additional surveys. Generally, trace levels were observed for other diseases in the Alberta survey. Aster yellows was also noted in some canola fields in 2023. Source credit: Michael Harding (Plant Pathologist with Alberta Agriculture), Kelly Turkington (Plant Pathologist with Agriculture and Agri-Food Canada), and the WFPM 2023 oilseed disease report.
Alberta clubroot distribution map (cumulative cases 2008-2023)
Distribution of clubroot in Alberta. Clubroot has been diagnosed in 5,532 canola crops in Alberta from 2005 to 2023, representing nearly 4,000 individual fields. Map credit: Strelkov et al. (2024). Can. Plant Dis. Surv.
Alberta canola disease survey results - blackleg
Prevalence and incidence of blackleg (2015-2023) in Alberta’s canola disease survey. Source credit: Michael Harding.

For more updates on the canola disease status in Alberta:

Alberta canola disease survey results - sclerotinia and verticillium stripe
Prevalence of sclerotinia stem rot and verticillium stripe (2016-2023) in Alberta’s canola disease survey. Source credit: Michael Harding.

Actions to take in Alberta in 2024

Helpful canola resources to use in 2024

To help understand and differentiate between common canola diseases and reminders to minimize disease impact and maximize crop potential, check out these top three Canola Council of Canada’s disease cycles, videos, online tools and disease management guides to help you manage canola diseases this year.

Published March 28, 2024 (Updated July 3, 2024)

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