Introduction

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3. Carry a boot brush and a supply of disinfectant in your vehicle at all times. Quaternary ammonia (General Storage
Disinfectant) is recommended as it is also registered for bacterial ring rot disinfection.
4. Wear coveralls or other protective outerwear that can be discarded or disinfected regularly.
5. Clean, washable, footwear is recommended and rubber boots are preferred.
6. Clean, wash, and disinfect your boots thoroughly on arrival at each field/farm/storage shed and before leaving.
7. Remove dirty outerwear, including boots before entering your vehicle.
8. Any tools to be used during the farm call (potato forks, shovels, soil probes, knives, etc) should be cleaned and
disinfected before and after use.
9. Maintain a detailed logbook of field/farm/storage shed visits.
Canola Diseases
Sclerotinia stem rot has been one of the most prominent diseases affecting canola in Manitoba and Saskatchewan for
the past 25 years. An important factor for disease development is environmental conditions. The disease is much more
widespread and severe during wet years. Fungicide applications are an important element in controlling the development
and spread of sclerotinia. Fungicide spray decisions are based on soil moisture, weather conditions, crop stage and density,
and disease history. The sclerotinia resting bodies (sclerotia) require moist soil conditions for up to 10 days for germination
to occur and the spore-bearing structures (apothecia) to form. Usually these conditions do not occur until the crop canopy
closes. The spores released from the apothecia utilize the canola petals as a food source and fall into the canola canopy
where they infect plants. Lesions form up and down the stem, wilting leaves and eventually killing the plant. Fungicide
should be applied between the 20 to 50 per cent flower stages to protect the petals from being colonized by the spores.
Blackleg caused by Leptosphaeria maculans affects canola and most crucifer field and vegetable crops. After many years
of low incidences, due to resistant canola varieties grown in the prairie provinces, the disease is gaining importance again.
High frequency of canola in crop rotations, accompanied by changes in the pathogen populations, has led to higher
incidences and severities in some fields. For an effective control, a 4 year crop rotation is highly recommended.
Clubroot is a soil-borne disease caused by a microbe, Plasmodiophora brassicae. Clubroot affects the roots of cruciferous
field crops such as canola, mustard, and camelina, as well as cruciferous vegetables and weeds. Clubroot has become a
significant problem for canola growers in some areas of Alberta and the pathogen has been detected in Saskatchewan
and Manitoba. Clubroot is a regulated pest in Saskatchewan under The Pest Control Act. Currently there is no provincial
legislation that regulates clubroot in Manitoba.
Invasion of the interior of the host roots alters hormone balance and leads to increased cell division and growth, resulting
in clubroot galls. These deformed roots have a reduced ability to absorb water and nutrients leading to stunting, wilting,
yellowing, premature ripening and shriv elling of seeds. The cause of these above-ground symptoms can be confirmed by
digging up suspect plants to check roots for gall formation. Clubroot affects canola yield and quality to a similar degree
as other diseases affecting water and nutrient uptake, and its impact depends on soil con-ditions and the growth stage of
the crop when infection occurs. Spore germination, infection and disease development are favoured by warm soils, high
soil moisture and low soil pH; however, the disease can still occur under conditions outside of the optimum parameters.
Infected roots will eventually disintegrate, releasing resting spores into the soil, which may then be transported by wind,
water erosion, animals/manure, shoes/clothing, vehicles/tires or earth tag on agricultural or industrial field equipment.
Resting spore numbers will decline over time when non-host crops are grown, but a small proportion can survive in soil for
up to 20 years. Clubroot is primarily a soil-borne disease; it does not infect seed but it may be found in soil attached to seed
or other plant parts. There are currently no seed treatments or foliar fungicides registered for control of clubroot on canola.
The following best practices are recommended for prevention and management of clubroot:
1. Plant susceptible crops, including resistant varieties, no more than once every four years. Although crop rotation will
not prevent the introduction of clubroot to fields that are free of the pathogen, it will restrict clubroot development
by limiting the increase of clubroot resting spores and preventing the increase of clubroot inoculum, as well as help
alleviate the impact of other plant pathogens.
2. Scout crops regularly and carefully.
º Identify suspicious above-ground symptoms including wilting, stunting, yellowing and premature ripening of
canola or other susceptible crops.
º Field entrances and approaches are likely to be contaminated with clubroot spores first. Therefore, symptoms will
often appear there first.
º Confirm cause of above ground symptoms by checking the roots for galls.
º Send sample of symptomatic plants into a commercial lab for confirmation of diagnosis.
Foliar Fungicides