Without proper fungicide treatments, late blight can devastate a potato crop.
Without proper fungicide treatments, late blight can devastate a potato crop.

A common potato virus and a fungus-like pathogen can team up to cause even more damage in potatoes.

Washington State University scientists found that potato virus S, or PVS, breaks down late blight resistance in potatoes.

The discovery will mean that potato breeders will have to take the virus under consideration when developing late-blight-resistant varieties.

Historically, PVS hasn't been a concern for growers in the United States.

“Now it’s demanding attention because of its role in making late blight disease more severe,” Hanu Pappu, a plant pathologist, said in a news release.

He and his colleagues developed a system to test for the three-way interactions among potatoes, the late blight pathogen and PVS.

Only one variety currently has late blight resistance.

Further research is needed to determine how the pathogens work together at the molecular lavel and how the host's genetic mechanisms affect the pathogens.

They published their results earlier this summer in the American Journal of Potato Research.