Fruit Rot

a disease of fruit trees, caused by parasitic Fungi Imperfecti of the genus Monilla and characterized primarily by the rotting, wrinkling, and desiccation of the fruits. In the USSR it is most widespread among drupe and small-seeded crops. Fruit rot of drupe crops (causative agent Monilia cinerea) is one of the most harmful diseases of apricots, peaches, plums, mazzard cherries, cherries, and cherry plums. Fruit rot of crops with small seeds is less damaging than that of drupe crops. Fruit rot of apple and pear trees is caused by the fungus M. fructigena (some apples in the Far East are parasitized by M. malt); fruit rot of quince is caused by M. cydonia.

The causative agents of fruit rot penetrate the plant primarily when there are mechanical injuries; they develop inside the tissues and winter in the organs of the trees. With the onset of warm, humid weather, the spores are carried to healthy trees by the wind, raindrops, and insects (mainly by fruit moths and snout beetles). Severe affection of fruits is fostered by dense plantings, dense tree crowns, planting orchards in lowlands, and cool, moist weather during blossoming.

Control measures include planting orchards on well-ventilated plots, gathering and packing fruits without mechanical injury, gathering and destroying diseased fruits, pruning and destroying diseased branches in the autumn or spring, turning over the soil around the trunks, and spraying trees with fungicides.