Further details on Xylella fastidiosa on coffee in Brazil
Xylella fastidiosa (EPPO A1 quarantine pest) was first found on coffee (Coffea arabica) in São Paulo, Brazil in 1995 (EPPO RS 96/169). Symptoms begin with apical and marginal leaf scorch, reduction of internode length of new flush, small pale green to yellow leaves, shoot dieback and overall plant stunting. Symptoms are more apparent in winter, especially in periods of water stress. Actual death of the plants due to the disease may take several years. The economic importance of coffee leaf scorch is unknown. Extensive coffee plantations have been eliminated in São Paulo. But as X. fastidiosa was not reported before 1995, losses were attributed to many other causes. However, it is now suspected that X. fastidiosa was responsible for this problem, as many remaining coffee plants tested positive for the disease. Studies were carried out on coffee leaf scorch and the Koch’s postulates could be verified, demonstrating that X. fastidiosa is indeed the causal agent of this disease. In addition, the relationships between the coffee strain and the citrus strain of X. fastidiosa (causing citrus variegated chlorosis) were studied. Antisera developed against cultured bacteria from both strains reacted positively against plant extracts affected with both diseases in dot immunobinding assays (DIBA). The polymerase chain reaction amplification products by both strains of X. fastidiosa were indistinguishable. The two strains appear closely related if not identical. However, it can be noted that in the field coffee leaf scorch usually occurs when coffee is adjacent to citrus affected by citrus variegated chlorosis. But citrus variegated chlorosis does not always occur when citrus are grown near diseased coffee plants.
Sources
de Lima, J.E.O.; Miranda, V.S.; Hartung, J.S.; Brlansky, R.H.; Coutinho, A.; Roberto, S.R. Carlos, E.F. (1998) Coffee leaf scorch bacterium: axenic culture, pathogenicity, and comparison with Xylella fastidiosa of citrus.
Plant Disease, 82(1), 94-97.