PP264

Exotic Diseases of M.M. Dewdney, J.D. Yates, M.E. Rogers, T.M. Spann

CITRUS VARIEGATED Leprosis Sweet CHLOROSIS (CVC) Scab (SOS)

Leprosis (early symptoms) Leprosis ( advanced symptoms)

CVC (upper side of leaf)

Sweet Orange Scab

Citrus Tristeza Leprosis on fruit Leprosis on mature fruit Leprosis bark scaling

CVC (underside of leaf)

CVC (small, hard fruit) Healthy fruit Citrus Black Spot (hard spot) Citrus Black Spot Citrus Black Spot (virulent spot) (false melanose) Citrus Tristeza Stem-Pitting

For more information, contact the University of Florida / IFAS Citrus Research and Education Center 863-956-1151, www.crec.ifas.ufl.edu, or your local county citrus extension agent: at http://citrusagents.ifas.ufl.edu/citrus_agents_home_page/citrus_agents_home.html

1. This document is PP264, one of a series of the Department of Plant Pathology, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. First published: April 2009. Revised December 2009. 2. Megan M. Dewdney, assistant professor, Department of Plant Pathology, Jamie D. Yates, coordinator for canker and greening extension education, Michael E. Rogers, assistant professor, Department of Entomology, Timothy M. Spann, assistant professor, Department of Horticulture, Citrus REC, Lake Alfred, Florida; Cooperative Extension Service, Institute of Food and Agricultural Sciences; University of Florida; Gainesville, FL 32611. Photo Credits: J.D. Yates, M.M. Dewdney, M.E. Rogers, N.A. Peres, L.W. Timmer, H.J.G. Korf

CITRUS VARIEGATED SWEET ORANGE SCAB CITRUS TRISTEZA Virus LEPROSIS CITRUS BLACK SPOT CHLOROSIS (CVC) (SOS) STEM-PITTING (CTV-SP)

Plant Tissue Cytoplasm or nucleus of Xylem Fruit rind and leaves Fruit rind Phloem Location infected cells

Warm wet conditions, presence Requires moisture; presence Sharpshooters, graft- Several of Brevipalpus Several species of aphids, Spread of susceptible fruit, and of susceptible fruit; splash transmitted, possibly seed mites budding and grafting presence of abundant inoculum by raindrops

Pathogen Xylella fastidiosa (Bacterium) Citrus leprosis virus Guignardia citricarpa (Fungus) Elsinoë australis (Fungus) Citrus tristeza virus

Reduced vigor and growth; tree not killed, but becomes Scattered pits after removing Symptoms localized on fruit, Tree Symptoms unproductive; symptoms may Extensive fruit drop if severe Unaffected bark from affected plants; leaves, or twigs appear in one branch or the depressed areas in the bark whole canopy

Severe chlorosis, reddish to brown lesions on the lower Chlorotic at first then may Small, round sunken necrotic side corresponding to yellow become brown with or Chlorosis and dieback may Leaf Symptoms spots with gray centers Unaffected areas on the upper surface; without a necrotic center; occur (uncommon) may resemble zinc deficiency smooth to touch in early stages

Twigs are brittle; bark is Stem/Twig abnormally thick; trunk and Unaffected Bark scaling, twig dieback As on leaves Unaffected Symptoms branches may have a ropy appearance

Necrotic lesions; hard spot, Small and hard with high Premature fruit drop, flat Young fruit have corky wart- false melanose, virulent spot acid; fruit remains on the tree; or depressed lesions with like pustules; tan to gray in Fruit Symptoms type symptoms; does not cause Small and misshapen may exhibit sunburn damage; yellow halo; often with brown color; mature fruit lesions decay; if severe, may cause normal color change centers become smoother extensive premature fruit drop

Flowering Off-season bloom Unaffected Unaffected Unaffected Off-season bloom

Mainly sweet orange, Varieties Affected Sweet orange All citrus, except Tahiti limes Sweet orange and , , sweet orange mandarins

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