American brown rot
Disease
American brown rot
Monilinia fructicola (G. Wint.)
Sclerotiniaceae: Helotiales
Distribution: Widespread; common to all fruit-growing regions in eastern North America.
American brown rot is common on apricot, peach, nectarine, plum and cherry. On fruit, small, circular, light brown spots enlarge rapidly to rot the whole fruit pre- and post-harvest. Rotted fruit shrivel, eventually becoming mummified. Infected blossoms wilt, turn brown, shrivel and persist into summer.
Oval sunken brown cankers develop at the base of infected blossom spurs and fruit of peach, nectarine and apricot; later, the bark at the edge of the canker cracks, gum oozes out and a callus forms.
Ash-gray tufts (sporodochia) bearing conidia of the fungus often develop over the surface of the infected tissues. The presence of conidia on lesions is the most distinctive characteristic of brown rot.