Galls are soft and spongy. The centers of older galls decay. They enter only through wounds. Crown gall is most damaging to young trees, either in the nursery or new orchard plantings. All peach rootstocks are susceptible to crown gall.
Preplant treatment is for prevention only.
Galltrol is a preparation of the biological control agent Agrobacterium K-84. It is effective only as a preventive treatment and is used as a root dip prior to heeling in or planting. It does not eradicate existing galls. Strains of Agrobacterium tumefaciens resistant to Galltrol and Norbac have been reported. Their occurrence is not widespread, but failure to control crown gall with these materials should be reported.