Diseases of Fruit Plantation Medicinal and Aromatic Crops

Flyspeck of apple

Flyspeck disease

Causal organism: Zygophiala jamaicensis E. Mason
Symptoms

Flyspeck appears on the fruit as well-defined groups of shining black dots which grow on the surface of the fruit. Areas of these dots are usually less than an inch in diameter. Fungi grow superficially on the fruit which can be wiped out from the surface easily.

Dissemination

Spores which produce primary infection are disseminated by wind during rainy season from overwintering sites. Spores which cause secondary infection are either wind or water borne.

Disease cycle

The fungus overwinters on infested apple twigs and reservoir hosts like brambles. Spores are then released during rainy season just before bloom to 1-2 months after bloom and are carried by wind to the host for causing primary infection. The spores germinate and create superficial fungal growth. Colonies become visible and spores are produced within three weeks. Secondary infection develops on the twigs and the apple fruit. Spores which cause secondary infection are also airborne and released after sunrise.

Management

Key times for management: The right time of apple infection starts from 10 days past petal fall. Periods of frequent infection occurs after 27 hours of leaf wetness sufficient rainfall and above normal summer temperatures are particularly favorable for an outbreak of this disease.
Management Options: A major decrease of disease can be attained through cultural practices.
Cultural Management Pruning for facilitating air and light penetration and thinning of fruit clusters can reduce incidence of this disease. Mowing nearby ditches and banks to decrease the population of nearby reservoir hosts may also be helpful.
Chemical: Bavistin spray @ 2gm /lit is effective.