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First Report of Citrus leprosis virus in Panama

Citrus is a rapidly expanding fruit crop in Panama with a planted area of approximately 14,000 ha, with the crop destined for both table and juice industries for local and foreign markets. Chiriqui Province in extreme western Panama borders Costa Rica and grows 4,300 ha of citrus that consists primarily of Valencia and navel oranges with the remainder grown throughout other provinces. Some plants in commercial groves in Potrerillos and Boquete in Chiriqui Province were found with leaf (chlorotic spots or rings), stem (necrosis), and fruit (localized ringlike or depressed lesions) symptoms similar to those caused by Citrus leprosis virus (CiLV) (3). In Potrerillos, wood samples about 3 years old were identified in two of the citrus groves, indicating that the infection was established on or before 1996. The mite Brevipalpus phoenicis (Geijskes) (Acari: Tenuipalpidae) was collected in all leprosis-infected or suspected groves in both Potrerillos and Boquete. CiLV is known to be transmitted by B. obovatus Donnadieu and B. phoenicis in Argentina and Brazil, respectively (3). To confirm the presence of this virus, 20 samples (12 from Boquete [B] and 8 from Potrerillos [P]) of leaf and fruit lesions were fixed in a modified Karnovsky solution and sent to Brazil for electron microscopic examination of thin sections. In 8 samples (2 from B and 6 from P) cytopathic effects were found characterized by a dense viroplasm in the cytoplasm and short, bacilliform particles (50 to 60 × 100 to 110 nm) in the lumen of the endoplasmic reticulum, features similar to those reported by Colariccio et al. (1). In 6 samples (5 from B, and 1 from P), the cytopathic effects were similar to those observed in Orchid fleck virus (OFV)-infected cells (2), with an intranuclear, electron lucent viroplasm and short, rodlike particles (40 to 50 nm × 100 nm) either within the nucleus or in the cytoplasm, as also previously reported for a sample of CiLV in Brazil (4). The symptomatology, presence of the mite vector, characteristic cytopathic effects, and presence of virions are considered to be evidence that CiLV is present within a 100 km² area of Potrerillos and 25 km² of Boquete in Chiriqui Province. This is the first report of the presence of CiLV in Central America, suggesting that the virus has spread northward from South America.

References: (1) A. Colariccio et al. Fitopatol. Bras. 20:208, 1995. (2) Y. Doi et al. AAB/CMI Description of Plant Viruses No. 183, 1977. (3) S. M. Garnsey and C. M. Chagas. 2000. Pages 57--58 in: Compendium of Citrus Diseases, 2nd Ed. L. W. Timmer et al, eds. APS Press, St.Paul, MN. (4) E. W. Kitajima et al. Virology 50:254, 1972.