MANAGEMENT OF GRAFT-TRANSMISSION OF THE PECAN BACTERIAL LEAF SCORCH PATHOGEN

摘要

Pecan bacterial leaf scorch disease (PELS) is caused by the bacterium Xylella fastidiosa. This bacterium has a very broad host range of plants, infecting over 100 species. In addition to pecan, other economically important hosts of X. fastidiosa include grape, citrus, coffee, blueberry, peach, and numerous hardwood and ornamental plants (Hopkins and Purcell, 2002). The pathogen inhabits the water-conducting tissue (xylem) of its hosts and restricts transport of water and nutrients through infected trees. The bacterium will move throughout infected trees from leaves to roots. In pecan, severe disease results in leaf loss, and reduced tree growth and nut weight (Sanderlin and Heyderich-Alger, 2003). Infection is usually permanent with annual disease development. The disease will likely reduce crop production throughout the life of a tree following infection. There are currently no practical management practices for PBLS after infection has been established in a pecan tree. The only way to manage PBLS is to avoid infection of trees.