OUTLOOK, Sask. – Surveys are underway in Saskatchewan to determine the incidence of black dot in potatoes.
Early findings indicate a low incidence of the disease, with silver scurf and rhizoctonia the most dominant diseases, followed by black dot.
Arcadio Viveros Guzman, a University of Saskatchewan graduate student from Mexico, is working with 11 seed potato growers at nine locations surveying potato diseases and evaluating control methods.
“The goal is to enhance the health of Canadian seed potatoes, especially to be exported to Mexico,” he told participants at the Saskatchewan Seed Potato Growers Association’s meeting in Outlook Aug. 16.
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Jill Thomson, research associate in the U of S plant sciences department, said black dot is an economic concern in the United States and England so there is a need to stay on top of it in Canada.
“We’re not saying it’s a trade issue now but diseases can be used as a marketing tool against us,” she said.
Black dot is a common superficial fungal disease, more prevalent in soil low in nitrogen or in warm, wet growing conditions.
The pin-head sized dots are visible to the human eye and can be found on tubers, stolons, roots and stems.
Thomson said it does not seem to affect yields. Appearance is the main concern.
“Anything causing a blemish on potatoes is an issue; people want potatoes to be looking perfect,” she said.
More troubling are the disease’s persistent soil-borne characteristics, said Thomson.
“It isn’t something that comes out of the ground with the potato; it stays in the ground,” she said.
Scott Anderson, president of the Saskatchewan Seed Potato Growers Association, said it’s important to watch what’s happening in other parts of the world where diseases such as black dot are on the rise even though Saskatchewan has a low incidence of such pathogens.
“We can see what we can do to keep it from becoming an issue in potatoes so we can keep a high quality product going out to our markets,” he said.
