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
|
Last modified: Thursday, 19 January 2012, 6:41 AM