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APSnet Image of the Week
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Citrus canker symptoms on grapefruit leaves.
Citrus scab symptoms on
sour orange fruit:
Citrus scab, caused by the fungus Elsinoe fawcetti, on sour orange (Citrus
aurantium).
The disease is common in residential plantings in South Florida.
Citrus scab symptoms on sour orange leaves.
Contributors: Dr. Shabbir A. Rizvi (CPPP), Chief Plant Pathologist, FDACS, Division of Plant Industry. CCEP-Miami, 1410 NW 78th Ave, Miami FL 33126-1608. E-mail: srizvi2933@aol.com or rizvis@doacs.state.fl.us. Dr. Timothy Schubert, Administrator III-Plant Pathology, DPI-FDOACS at Gainesville.
Background: Various types of Citrus are traditionally grown by homeowners in Dade and Broward counties of South Florida. Foliar diseases caused by fungal and bacterial pathogens are common in this area due to favorable weather conditions (warm temperatures and abundant rainfall during shoot emergence) and widespread culture of susceptible Citrus. Two of the most common diseases are Citrus Canker and Scab. The Citrus Canker disease, caused by the Asiatic form of the bacterial pathogen Xanthomonas axonopodis pv. citri, is causing serious problems in residential plantings in South Florida. Since there are no effective bactericides available, host eradication is the only option for control.
Scab, caused by the fungal pathogen Elsinoe fawcettii, is restricted to sour orange. The pathogen infects young shoots, leaves, and fruits of susceptible cultivars. The yield and quality of juice can be reduced in highly susceptible cultivars that become severely infected. The disease can be controlled with fungicide sprays.
APS publication number: IW00011
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