Fusarium lurks in potatoes, warns crop pathologist

Mike Harding doesn’t usually favour sensational titles for the presentations he gives to farmers.

On March 1, the Alberta Agriculture crop pathologist made an exception with his talk to potato growers on Fusarium: The Silent Storage Killer.

Harding said fusarium in potatoes “flies under the radar” be-cause it can develop slowly in stored product and do major damage before it is noticed.

“Fusarium species, these are fungi, and they’re present around the world,” he said.

“They’re oftentimes more serious in potatoes that we try to store for long periods of time.”

The three fusarium diseases on potato include dry rot, foliar wilt and seed piece decay.

Harding said dry rot can cause major financial losses to growers from seed loss, grading discounts at the processor and additional processor dockage.

“The more we can manage it, the more money we can put back into the pockets of people in the potato industry,” he said in a presentation to growers of fresh market and table potatoes.

Studies show fusarium was present in 2013-15 in 65 to 85 percent of Alberta fields tested.

“We can go into almost any potato field or potato storage and isolate fusarium,” Harding said.

Producers can manage or control it by using clean seed stored in a disinfected facility.

Tubers should be warm before cutting for seed, and the cutting equipment should be disinfected before use.

There are several registered fungicides for seed treatment, and Harding encouraged producers to vary their use to avoid development of resistance.

“The more we rotate active ingredients from different classes, the better resistance management.”

At harvest, potatoes without wounds will generally be safe from fusarium.

Fungicides are available to treat spuds in storage.

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