Potato industry continues fight against late blight

By Trevor Busch
Taber Times
tbusch@tabertimes.com

As the sun continues its slow climb back to northern latitudes, potato producers in southern Alberta are readying themselves for another growing season.

Acreage is primarily based on contracts, so just how many potato acres will be planted for 2015 is still anyone’s guess.

“We’re just in the early stages of contract negotiations. Until that is settled, nobody really knows,” said Terence Hochstein, executive director of the Potato Growers of Alberta. “Your seed acres are going to remain about the same. The fresh acres will probably be up a little bit this year, we’re hoping to top 3,000 acres there. But as far as process acres, we don’t know that until the contracts are signed.”

In 2014, 53,000 acres were planted in total across the province, and 51,750 were harvested. Of that total, 40,000 acres consisted of process potatoes, and 9,500 acres of seed. The balance was made up of 3,500 acres of fresh potatoes, up about 500 acres from 2013.

“Considering what mother nature gave us in the fall, it turned out okay,” said Hochstein. “Quality was a little bit less than it has been in years past, compared to what we normally get, but nothing that we couldn’t handle. Quality was down, the size profile was a little bit smaller than normal. The rain at the end of August and an early frost hurt the potential quite a bit.”

Farmers usually shoot for mid-April in getting their seed acreage into the ground.

“It’s all over the place. All things considered, we hope to get started a little bit earlier than we did last year. Last year we got started about 10 days late. Roughly April 15, if mother nature co-operates,” said Hochstein.

Late blight has been problematic for producers in recent years, but awareness can help mitigate issues in future.

“Over the last couple of years we’ve really worked hard on this late blight initiative and making the public aware, and all of the growers aware of it, and we’re going to continue down that road and try to eliminate it as best we can,” said Hochstein. “We continue to work with the market gardens, the greenhouses, and the public. But you don’t know until you see what weather gets thrown at you. If you get a hot, dry summer, then a lot of that problem goes away.”

Signs of late blight include dark, water soaked lesions on leaves; yellow edges or margins not contained by leaf veins; older lesions will turn black or brown in colour and may become brittle; and a small amount of spore production, which appears as a fluffy white growth on the edges of the lesions, may occur on the underside of the affected plant.

Late blight was responsible for the Irish potato famine of the 1840s, which resulted in the death and mass emigration of millions of Irish. The fungal pathogen, phytophthora infestans, belongs to a group of fungi called “water moulds”. It thrives and produces spores under a humid, moist environment and causes infection only when free water is present on plants. The pathogen is highly aggressive and can potentially infect all plant parts, causing rapid die back and death. Different forms of the pathogen can easily travel by wind and rain, and it survives between crops and over winter on infected seed potatoes, cull potato piles, volunteer potatoes, and diseased organic debris.

Tomato plants can also be a source of late blight, which attacks both potato and tomato plants equally.

Hochstein believes the potato industry has a bright future in Alberta, and sees room for expansion.

“We continue to remain optimistic, and hope that it continues to expand. There’s opportunity for growth in the industry, and we hope to be a part of it.”