Press release, July 30, 2009
by Dr. Vern Grubinger, University of Vermont Extension
It’s been an exceptionally rainy and cool summer and one of the consequences is that Late Blight disease has been reported in every corner of Vermont and across the Northeast. With these weather conditions Late Blight rapidly kills the foliage of tomato and potato plants. Many hundreds of farmers and gardeners have already been stricken, and it is likely that the situation will get worse unless the weather turns hot and dry.
Late Blight is caused by a fungus, Phytophthora infestans, and it’s the same disease that led to the Irish potato famine almost 150 years ago. The disease is not directly harmful to people as it only infects potatoes, tomatoes, and some related weeds.
The good news is that the disease does not persist in the soil from year to year, so with proper action, farmers and gardeners should be able to avoid this problem next year. In addition, infected potato crops may still yield edible tubers if the diseased foliage is destroyed soon after infection is observed.