Submitted to: International Organization of Citrus Virologists Proceedings
Publication Type: Abstract only
Publication Acceptance Date: 11/7/2004
Publication Date: 11/30/2004
Citation: Villalobos, W., Moreira, L., Derrick, K.S., Beretta, M.J., Lee, R.F., Rivera, C. 2004. Occurrence of citrus blight in costa rica. International Organization of Citrus Virologists Abstracts, Page181. Interpretive Summary:
Technical Abstract: Technical Abstract: Since 1997, citrus blight (CB) symptoms were observed in several groves in the northern region of Costa Rica, the country=s most important citrus area (more than 25,000 ha.). The symptoms include a general decline of the tree canopy with wilt, off-color leaves, leaf drop, twig dieback, small fruit, poor growth flushes, and tree death. The CB symptoms began in 7-yr-old orange trees of Valencia and Pineapple grafted on Carrizo citrange rootstock. Since 1997, six percent of the trees in this area have been replanted annually due to blight. To confirm CB, the dot immunobinding assay (DIBA) was used to detect the p12 CB-associated protein in old leaves. DIBA showed a positive reaction in 20 or 22 symptomatic trees. For additional CB diagnosis, assays for zinc accumulation in wood and water uptake into the trunk were carried out using eight healthy and 16 affected trees previously shown to be positive for p12 by DIBA. The zinc content test showed a two or three times higher concentration in the blight-affected trees compared to the healthy trees. The healthy trees (8/24) had a water uptake average of 14 ml, while the 16 CB-affected trees had virtually no uptake. To our knowledge, this is the first report of the presence of citrus blight in Costa Rica affecting oranges in the commercial areas.