ˈ ̷ ̷ˌ ̷ ̷ noun
: any of several rots involving the central part of a plant or plant organ: as
a. : disintegration of the heartwood of a tree (as by fungi of the genus Fomes )
b. : a disease of beets and rutabagas caused by a fungus ( Mycosphaerella tabifica ) that brings about decay of the heart and blighting of the leaves
c. : a rot of sugar beets caused by boron deficiency