Xylella fastidiosa is associated with pecan leaf scorch.
Several different leaf scorch symptoms occur on the foliage of pecan (Carya illinoinensis). These different symptoms have been associated with various causes (environmental stresses, nutritional problems, mites and pathogens). One type of leaf scorch is characterized by necrosis beginning at the tips or margins of the leaflets and progressing toward the midrib and base of the leaflets. The most distinctive feature of this type of leaf scorch is a dark brown, black, or purplish band of tissue at the interface of the necrotic and green leaflet tissue. Affected leaflets abscise from a compound leaf, while leaflets without symptoms remain on the rachis. When the attack is severe, the whole leaf can fall. Several fungal genera have been reported to be associated with this disease over the last 25 years which was therefore called ‘fungal leaf scorch’. Recently, by using an ELISA test it was found that Xylella fastidiosa (EPPO A1 quarantine pest) is associated with pecan leaf scorch. Further work is needed to determine the exact etiology of this disease.
Sanderlin, R.S. (1998) Evidence that Xylella fastidiosa is associated with pecan fungal leaf scorch.
Plant Disease, 82(2), p 264.