Disease Threatens What’s Left

From 10,000 feet, the muddy Prairie fields below soaked with unprecedented rains this spring can be described in one word: dismal.

The Canadian Wheat Board (CWB) predicts farmers will seed only 19.2 million acres of wheat and 6.6 million of barley – the smallest acreages since 1971 and 1965, respectively. It estimates 8.5 million to 12.5 million acres will not get seeded at all.

Meanwhile, the millions of acres that were sown have an increased risk from disease, making field scouting essential.

Last week, Jason Voogt, Cargill’s agronomy manager for eastern Manitoba, discovered leaf rust in fields of AC Domain south of Winkler and northwest of Carman.

Domain and AC Barrie are more susceptible to leaf rust than newer wheats. But with leaf rust arriving three weeks earlier than normal it could be a harbinger of worse to come.

Tan spot is also widespread and conditions are shaping up for the same to be true for fusarium head blight. Soon-to-be-flowering winter wheat crops are especially vulnerable.

Last week provincial officials were disturbed to discover late blight-infected tomato seedlings at retail outlets in Brandon and Winnipeg. The same disease responsible for the infamous Irish potato famine in the 1840s could infect Manitoba’s commercial potato crop. Gardeners are urged to destroy sick tomato plants, said Brian Wilson, potato specialist with Manitoba Agriculture, Food and Rural Development (MAFRI).

Potato growers are advised to start spraying crops immediately.

“In effect the risk has gone up because we do have an inoculum source so farmers will have to be more aggressive with their fungicide program and be diligent all throughout the rest of the growing season,” Wilson said.

Rains June 11 have further heightened the risk.


Normally, wheat rust doesn’t appear in Manitoba until the end of June, or early July, but strong southerly winds are believed to have blown the spores directly from Texas and Kansas, said Vikram Bisht, a MAFRI plant pathologist.

Leaf rust pustules are dusty yellow to bright orange, small round to oval spots found on

“In the last 40 years we haven’t seen conditions, over such a large area, this bad.”


the leaves and sheaths of cereal crops, says MAFRI’s web page.

In some states a fungicide is recommended if there is an average of one leaf rust pustule per leaf. Spraying is recommended if the threshold is met in three of the five spots sampled in a field.

With so much moisture around thick crops with early infection could be vulnerable.

There are many fungicides to choose, including BASF’s newly registered Caramba, which also suppresses fusarium head blight, but only when applied at 20 per cent flowering.


Much of agro-Manitoba has received double the normal rainfall since April 15 – places such as Elm Creek, triple the average at 225 mm.

Much of central and northern Saskatchewan received record rainfall during April and May. Saskatoon shattered its previous record by 50 mm.

“Certainly this is an unprecedented event in Western Canada,” Bruce Burnett, director of the CWB’s director of weather and market analysis told reporters June 11. “In the last 40 years we haven’t seen conditions, over such a large area, this bad.”

Jack McKinnon agrees. After a flying with a reporter June 13 from Carman to Langenberg, Sask. and Ninette, Man., the owner of Prairie Agri Photo said he’s never seen so much devastation in his 30 years of photographing Prairie fields.

Potholes are full of water. Whole fields appear unseeded, while many of those planted have drowned.

The CWB is predicting close to average yields. Notwithstanding continued rains, it’s unlikely spring wheat yields will average less than 33 bushels an acre, Burnett said. That would result in 13 million tonnes of production, down 27 per cent from last year.

“Certainly this is going to be one of the most challenging years in Western Canada for farmers producing crops,” Burnett said. “The economic impacts are probably going to last long through not only this year but next year as well.”

Two cases of sunflower rust have just been confirmed in Manitoba, two weeks earlier than last year and last year’s infection was early, said Kristen Podolsky with the National Sunflower Association of Canada. Sunflower rust can be controlled with BASF’s Headline fungicide. Full registration for sunflower rust expected by month’s end. If it doesn’t happen an emergency registration, which Headline received last year, will be sought. [email protected]

About the author


Allan Dawson

Allan Dawson is a reporter with the Manitoba Co-operator based near Miami, Man. Covering agriculture since 1980, Dawson has spent most of his career with the Co-operator except for several years with Farmers’ Independent Weekly and before that a Morden-Winkler area radio station.



Stories from our other publications