Diseases of Fruit Plantation Medicinal and Aromatic Crops

Citrus scab

Causal organism: Elsinoe fawcettii and Sphaceloma fawcettii

• Commons cab or sour orange scab - Elsinoe fawcettii
• Sweet orange scab – E. australis
• Tryone scab – Sphaceloma fawcettii var. scabiosa
Symptoms

• Whitish, raised, circular, scabrous growth observed on the fruits, changing to grayish color, decrease in the fruit size, quality and ultimately fruit fall off.
• On lower surface of infected leaves whitish scabrous growth corresponding upper surface, concave dippression can also be seen.
Etiology

• It is believed that the pathogen perpetuates and survives in adverse season as perithecium.
• Secondary spread occurs through the conidial which are mostly produced on the host surface.
• Conidia are produced at 7 °c& 33°c temperature and at 66-100% RH conditions on young lesions.
• Conidia from old lesions are dispersed during rains but only to a short distance.
Management

• Collect infected leaves and burn them.
• Disease can be controlled by spraying with 1% Bordeaux mixture or difolatan and benomyl.
• Chemical:Carbendazin spray @1.25gm/lit
• Avoid excess N application and use recommended dose of potassium in the soil