COUNTY AG NEWS

Late blight in Central Wisconsin

Vegetables and field crops can sustain significant yield reduction from fungal diseases or in the case of late blight, total crop loss. At this time, late blight has been found at one location in southeastern Wisconsin.

Gardeners in our area often have issues with their plants dying form a blight type of disease. In nearly all cases this is from early blight. Early blight is a fungal disease that will overwinter in our soil and then as our new plants are growing rain water splashes the overwintering spores onto the plants and the plants then become infected. Tomato and potato plants become infected with early blight on leaves and stems closest to the ground. The infection then expands upwards in the plant. Late bight may infect the plants at any point.

Late blight is a potentially destructive disease of potatoes and tomatoes caused by the fungal organism, Phytophthora infestans. Late blight is the disease that caused the Irish potato famine in the late 1800’s. This pathogen is referred to as a ‘water mold’ since it thrives under wet conditions.

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