Late blight won’t affect availability or quality of Wisconsin’s potato crop

News about late blight has raised concerns among retailers, processors and other users about the availability and quality of stored potatoes in Wisconsin this winter, reports A.J. Bussan, University of Wisconsin–Madison extension vegetable specialist. But Bussan doesn’t think that either quality or quantity will be a problem.

“The volume of stored potatoes does not appear to be in jeopardy due to issues of late blight at this point in time,” he writes in a newsletter article to growers. “All growers have been taking preventative action to manage late blight since reaching critical severity values six to eight weeks ago and detections in production fields have been limited to a single case. With vine kill actively ongoing throughout the state and storage crop due for desiccation within days, the threat of late blight decreases.

“Late blight cannot survive unless living potato/tomato tissue is present. Growers are thoroughly scouting desiccated fields for any signs of green tissue. Fungicide should continue to be applied if stems or leaves remain viable or green after vine desiccation,” Bussan adds.

Typically, about 80 percent of the state’s crop is put into storage until needed by processors. The last time Wisconsin had a late blight outbreak in potatoes was 2002.

For more information, contact Bussan at 608-262-3519 or 608-225-6842.