Potato Disease
a disease or murrain produced by a fungus, Peronospora infestans. It generally first attacks the leaves and stems of the plant, forming brown spots on them in July and August.
By this time the fungus, which first penetrated the tissue of the leaf, has thrust forth through the stomates its conidia-bearing filaments. The leaves soon afterward die. Next the tubers POTATO FLY are attacked and decay, either in a moist manner, attended by a disagreeable odor, or by a drying up of the tissue. The potato disease first appeared in the United States. In 1845-1847 it caused the failure of the potato crop in Ireland, producing famine. It has never since completely disappeared. When it is prevalent, the potatoes should be powdered with flowers of sulphur before be ing planted.
POTATO FLY (Anthomyia tuberosa), a dipterous insect of the same genus with the radish fly, cabbage fly, turnip fly.
In its perfect state it is very like the house fly. The potato-frog fly (Euteryx solani, Curtis) and the caterpillar of the death's-head moth (Acherontia atropos, Linn.) feed on the leaves and stems of potatoes, but rarely do serious damage.