University of Maryland College of Agriculture and Natural Resources has issued an alert to Maryland gardeners concerning an invasion of Late Blight of tomatoes and potatoes. Though it is called Late Blight, the fungal disease can attack plants at any time during the growing season.
According to Jerry Brust, integrated-pest-management vegetable specialist for the University of Maryland Extension, “Usually the disease shows up in late summer and is a moderate problem; however, this year—thanks to a prolonged period of wet and cool spring weather—it was first diagnosed in mid-June and confirmed up and down the Eastern seaboard in early July. Compounding the problem, large retail stores on the East Coast unintentionally sold blight-infected plants, resulting in an increased distribution of the disease.”
Late blight first appears as dark, water-soaked spots on leaves which shrivel and die. Dark brown spots can also appear on stems and fruit. The Home and Garden Information Center of the Maryland Cooperative Extension has an excellent fact sheet on Late Blight. If you have questions about whether your plants have Late Blight you can contact a the Maryland Cooperative Extension at (800) 342-2507.