According to Amanda J. Gevens, Associate Professor & Extension Vegetable Plant Pathologist at the Dept. of Plant Pathology, UW-Madison, a new late blight strain type, US-25 has recently been identified in New York State. According to Prof Gevens, this strain has, to this point, been found only on tomato. In a weekly newsletter, she says that Dr. Christine Smart, Professor at Cornell University, has been keeping extension and research pathologists informed of this new type, which is now known to be mefenoxam resistant and of the A2 mating type. Prof Smart reported that under lab conditions, US-25 will infect potato as well as tomato. Prof Gevens further says that “all samples tested from the Great Lakes region, USA region including WI, IL, and MI to date, have been US-23. The MN tomato late blight finding from several weeks back was not genotyped.”
Outside of the Great Lakes region, late blight detections have been made this season in FL, NC, NY, PA, and WA. While US-23 (mefenoxam sensitive and A1 type) has been most predominant, US-8 has re-emerged in WA and this new US-25 type has emerged in NY, according to the scientists.
For more information about the new US-25 type, and information about late blight in the Great Lakes region, please contact Prof Christine Smart (cds14@cornell.edu) or Prof Amanda Gevens at gevens@wisc.edu
