noun
: a blight of plants in which symptoms appear late in the growing season: as
a. : a disease of solanaceous plants and especially of the potato and tomato caused by a fungus ( Phytophthora infestans ) and characterized by decay of leaves, stems, and in the potato also of tubers
b. : a leaf spot disease of celery caused by a fungus ( Septoria apii or S. apii-graveolentis ) — see celery blight