Details on the situation of Citrus blight in Costa Rica
The etiology of citrus blight (EPPO A1 list) remains unknown; a pathogen is suspected but has not yet been identified. This disease was first reported in the 1980s in Brazil, where it is now responsible for the removal of nearly 10 % of trees per year. Since 1997, symptoms of citrus blight have been observed in several groves in northern Costa Rica (the major citrus-producing region of the country covering approximately 25,000 ha). Symptoms included a general decline and wilt of tree canopy, leaf drop, twig dieback, small fruit, delayed blossom, poor growth and death. A survey done in the Guanacaste province revealed symptoms in 7-years old orange trees (Citrus sinensis cvs Valencia and Pineapple) grafted on Carrizo citrange (C. sinensis x Poncirus trifoliata). Since 1997, 6 % of the trees in this area have been replanted annually because of citrus blight symptoms. Similar situations were also observed in other groves in the northern citrus area. Laboratory tests (dot immunobinding assay to detect a protein associated with the disease, and tests of zinc accumulation in the trunk wood and water uptake) gave positive results and indicated the presence of citrus blight in symptomatic trees. This confirms earlier reports of citrus blight disease in Costa Rica (see EPPO RS 99/135).
Sources
Villalobos W, Moreira L, Derrick KS, Beretta MJG, Lee RF Rivera C (2005) First report of Citrus blight in Costa Rica.
Plant Disease 89(1), p 108.