If you collect your own scion wood, you should try to observe the trees that you collect wood from during the summer and fall months for PBLS symptoms. It is possible for one or a few limbs or branches to be infected or for the entire tree to be infected. If any part of a tree is infected, you should avoid collecting scion wood from that tree. In some cases, it is not always possible to collect scion wood of a particular cultivar from a noninfected tree. It is also possible that PBLS symptoms may be overlooked or missed. In situations where you are not sure if the scions came from noninfected trees, prior to grafting, you can subject the scions to a hot-water treatment that has been tested and shown to be effective in eliminating the PBLS pathogen from the scions. While the treatment may not be 100% effective, it can greatly reduce the degree of infection of new trees from scion wood.
For instructions on how to use the hot-water treatment to treat your scions, go to the Procedure for Hot Water Treatment of Pecan Scion Wood article on the Plant Pathology page of the Pecan Research-Extension Station Web site.
Question answered by plant pathology researchers at the Pecan Research-Extension Station.