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late blight lesion on potato

Potato late blight lesion.  Image courtesy of Jean Ristaino, NC State University.

Welcome to USA blight, a national website that acts as an information portal on late blight.  You can report disease occurrences, submit a sample online, observe disease occurrence maps, and sign up for text disease alerts.  There are also useful links to a decision support system, and  information about identification and management of the disease.

Late blight of potato and tomato caused by Phytophthora infestans is a devastating disease worldwide and led to the Irish potato famine in 1845. Under favorable weather conditions, tomato and potato crops can be destroyed within days. Yield losses caused by late blight and the cost of control measures have been estimated to exceed 6.7 billion dollars annually and the disease is a major threat to food security worldwide.   

Report of late blight in Onondaga Co. featured on North Country Public Radio

Late blight has been reported in Onondaga Co., NY on tomato. Initial findings indicate that the strain detected is not a previously observed strain, and more evaluation is currently being done to learn more. Additional reporting on this news was featured on a gardening segment on North Country Public Radio. The segment can be listened to here.


Phytophthora nicotianae producing late blight-like symptoms in NC

Outbreaks of Phytophthora nicotianae have been reported on tomato and potato in North Carolina. These infections of P. nicotianae are producing foliar lesions similar to symptoms of late blight infection. Growers are encouraged to monitor their crops carefully and to submit samples for further analysis if late blight or P. nicotianae is suspected. As of June 12, no late blight has been detected in the state. More information on differences between the two causal species, recommended treatment options, and photos of symptoms can be found in articles on the NCSU Plant Pathology Extension website:

Phytophthora diseases occurring on fruiting vegetables in WNC
Phytophthora nicotianae causing severe disease on potato and tomato in North Carolina



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