Late blight has very recently been reported in potato plantings in coastal Maine (Woolwich, in Sagadahoc County) and an additional outbreak was reported in Penobscot County. Late blight has also been reported in the St. Andre area of New Brunswick, Canada. Conditions for the development of late blight have been very good in Maine and growers should be on the alert to catch any early symptoms on their plants and be ready to apply appropriate control measures. Typical symptoms will be water-soaked lesions on the leaves with fine, white cottony mycelium on the undersides. Infections on the stems appear as dark, almost black lesions.
Late blight spores can travel over 40 miles under the right conditions (wet and warm) and the spread can be very fast. We are encouraging all growers to carefully and regularly inspect their plants for this disease. Please report any suspicious symptoms to us at our UMaine Extension Pest Management Office at 207-581-3883 or 1-800-287-0279 (in Maine) or e-mail Bruce Watt, our Plant Disease Diagnostician (email@example.com). Samples should be sent in a sealed plastic bag with a dry paper towel to keep them fresh. Visit umaine.edu/ipm/ipddl/how-to-send-a-plant-sample/ for more detailed shipping and sample preparation directions, as well as a submission form for any samples you send to us.
More information about Late Blight:
- Late Blight Fact Sheet (PDF)
- Late Blight Prediction in Maine (PDF)
- Photos of Symptoms
- Late Blight: Grower and Farm Stand Alert (Part of our UMaine Extension apple, small fruit and vegetable research program at Highmoor Farm) (download pdf)
- University of Maine Cooperative Extension’s Late Blight publication (Published 2010)
- Gardening After Late Blight
- Late Blight on Tomato and Late Blight on Potato (Cornell University–includes photos)
- Organic Management of Late Blight of Potato and Tomato with Copper Products
- Fungicide Listing for Late Blight, Early Blight and Septoria Control in Tomato