Recognizing Exotic Diseases of Citrus

1. Recognizing Exotic Diseases of Citrus CVC Healthy Healthy CVC Fruit size is reduced, fruit is sweet and ripens early, seed is not aborted. Jeff Lotz, FDACS, FL S. E. Halbert, FDACS, FL The disease begins with chlorotic sectoring in the tree branches; thus the name: Huanglongbing (yellow shoot). The disease is spread by psyllids; heavy infestations with nymphs result in an obvious waxy excrement. Citrus leprosis is caused by a virus spread by Brevipalpus sp mites. Control of mite vectors and trimming of infected branches account for 25% of the cost of citrus production in Brazil; left untreated the disease will kill a tree in 3 years. Fruit from infected trees drops early and has a bitter taste. The leaves have a blotchy mottle, often with a yellow mid-ribs. Brevipalpus mites on a citrus leaf Fruit remains green on the basal end, seed is aborted in affected fruit, and the fruit may be lopsided. HUANGLONGBING (Citrus Greening) present in Florida Lesions occur on twigs, leaves, and fruit. Leprosis-affected fruit falls early CITRUS LEPROSIS Citrus Canker (Xanthomonas axonopodis pv citri) Affects limes, grapefruit, and trifoliates most severely. Causes lesions on leaves, twigs, and fruit, causing fruit drop. Spread by rain-driven wind and infested equipment. A quarantine disease present in Florida. Infected trees are chlorotic and become stunted and decline. Leaves have interveinal chlorosis with gum deposits on the underside. Report anything suspicious to your State Department of Agriculture Sharpshooter insects spread the disease. CITRUS VARIEGATED CHLOROSIS (CVC) caused by Xylella fastidiosa Poster prepared by the USDA ARS National Clonal Germplasm for Citrus and Dates Riverside, CA 92507 Richard Lee rivrl@ars-grin.gov Phone 951 827 4399