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Clubroot Keeps Its Distance In 2009

Manitoba canola growers can breathe a little easier with news that a new plant disease spreading in Alberta hasn’t made it to this province – yet.

A field survey last summer found no signs of clubroot, a disease which attacks canola as well as vegetables, said Ingrid Kristjanson, a Manitoba Agriculture, Food and Rural Initiatives farm production adviser.

But she warned canola producers attending St. Jean Farm Days to be on the lookout for clubroot, which is gaining a foothold in Alberta.

In particular, Kristjanson urged people visiting Alberta to clean their equipment, vehicles, tools and even footwear to avoid transporting this soil-borne disease back home.

Clubroot is a worldwide fungal-like disease that attacks crucifer crops (canola, mustard, broccoli and cabbage). It reduces yield and quality by restricting water and nutrients to the seed. Its spores can survive in the soil for years.

In Manitoba, clubroot has previously been detected in vegetables (in 1925 and again during the 1980s) and once in canola at low levels (2005).

But there have been outbreaks in central and southern Alberta since its detection near Edmonton in 2003. Seventeen counties and the City of Edmonton have been affected. Some counties are enforcing a virtual quarantine with four-to five-year rotations in an effort to control the spread of clubroot, Kristjanson said.

No clubroot symptoms were observed in Saskatchewan canola fields in 2009, according to the province’s Agriculture Department.

Manitoba has a “Clubroot Action Team” to monitor for the disease and provide information about it, Kristjanson said.

Symptoms of clubroot include delayed flowering, wilting and leaf yellowing. But the classic symptom is a swelling or “clubbing” of the root, hence the name.

Agronomists say yield losses from clubroot are about half the percentage of infected stems. If 100 per cent of plants are infected, yield losses will be 50 per cent. With 10 to 20 per cent of plants infected, losses will be five to 10 per cent.

In some cases, severe field infes tat ions have caused total yield loss, according to Alberta Agriculture and Rural Development.

EQUIPMENT HYGIENE

Kristjanson encouraged producers to guard against clubroot by cleaning tillage and seeding equipment to get rid of dirt clumps. People returning from Alberta who may have visited infected areas should sanitize vehicles and equipment.

She said crop rotation is the best guard against clubroot. Fields should be planted to a non-susceptible host crop (cereals, flax, sunflowers and pulses) for at least four years if initial symptoms of the disease are detected.

The MAFRI lab can verify if a plant disease really is clubroot.

While clubroot is so far only a threat to Manitoba canola growers, other diseases were present and active in their fields during 2009.

Kristjanson said a survey of 140 canola fields found sclerotinia in 91 per cent of fields and blackleg in 56 per cent. [email protected]

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