Diseases of Fruit Plantation Medicinal and Aromatic Crops

Black knot

Causal organism: Apdiosporina morbosum, a fungus

• Pathogen infects Plum and cherry plants throughout the states having temperate climate.
Symptoms:

1. First year symptoms include light green swellings on twigs.
2. Next spring these become enlarged and turned velvety black.

Control Recommendations

1. Remove all knots by first of April and burn.
2. Limit pruning to late winter.
3. Treat branches with lime sulfur at green tip, full bloom and petal fall