Researchers identify new strains of pathogen that could threaten U.S. growers

The fungal-like organism that causes late blight affects both tomatoes and potatoes. Unlike the other 60 Phytophthora species that produce soil-borne, root-rotting diseases, late blight infects foliage, stems, potato tubers and tomato fruits. Lesions can occur on both leaves and stems, and usually occur after periods of wet weather. Scientific research of Phytophthora infestans, or late blight, has been an issue of concern ever since the plant disease triggered the Irish potato famine of the 1840s. Plant pathologists say it was the first plant disease for which a microorganism was proved to be the causal agent, leading to the birth of plant pathology as a science. Researchers warn the ongoing battle with late blight may become either more difficult or less difficult in the years ahead. On the one hand, newer species of the pathogens are being discovered and could represent a threat to U.S. growers. But researchers at the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) say new findings could also help prevent more genetic strains of the potato and tomato-killing late blight pathogen from crossing the U.S.-Mexico border. More