Nemagard root stock, which is generally not recommended for Georgia, shows resistance to M. incognita and M. javanica but has no resistance to M. hapla or M. arenaria . All efforts to control root-knot nematode should be made prior to planting an orchard. Crown gall occurs as tumorous rough surface growths on roots and crowns of trees. Galls can be verb smallto more than a foot in diameter. The bacteria enter the tree through fresh wounds.
Crown gall can be a veryserious problem for nurserymen.
Trees infected when very young may soon die. Older trees may become weaker, but generally do not die from crown gall. Once land has become infested with the bacterium by introduction of contaminated plants or soil, it must be regarded as permanently infested. Infected nursery stock should never be planted. Very small crown galls can be confused with galls caused by root-knot nematode.