Phytophtora – Late Blight

Phytophthora- late blight Common name Phytophthora- late blight Potato blight Causal agent It is caused by the water mold Phytophthora infestans, and mainly infects tomato and potato crops. Scientific name Phytophthora infestans Symptoms & Signs Dark green and purplish-black lesions are seen on the leaves, stems, and petioles. The lesions merge together and grow in size as the disease progresses. It also shows necrosis on the site of lesions as well as chlorotic borders around the lesions. The lower surface of the leaves also shows spore-producing structures. As the spores enter the soil, potato tubers also get infected and rot. Transmission Phytophthora is a fungi-like species, hence, it transmits through spores. The spores travel by wind, or water to young potato plants where they enter the tubers and infect it. Cool, wet temperatures and environmental conditions greatly favor the spread of this disease. Time of concern Early spring to late summer Common hosts Potato Tomato Petunias Nightshade