CLITOCYBE ROOT ROT OF WOODY PLANTS 



21 



If it is found practicable to treat the tree, cut off and completely re- 

 move all dead roots flush with the root crown or living roots from 

 which they branch. Remove all dead oak or other foreign tree roots 

 that may be found under the tree being treated. All bark lesions that 

 may occur at the base of the trunk or on the root crown, lateral roots, or 

 taproot, in case the taproot is not dead, should have the dead or in- 

 fected bark cut out carefully back to healthy bark and down to sound 

 wood. Carefully inspect the lateral roots for local lesions, particu- 

 larly at their juncture with the root crown. Remove all infected roots 

 and chips of bark and wood cut away and burn them, since allowing 

 such infected material to remain in the soil may lead to redevelop- 



Figuke 10. — Grapefruit tree on rough lemon stock given complete surgical treat- 

 ment for Clitocybe root rot, showing points where the dead roots and diseased 

 areas of bark were cut out. 



ment of the disease. A piece of heavy paper placed under the exposed 

 roots will greatly facilitate the collection and removal of such mate- 

 rial. All trees not worth treating should be removed, together with 

 their roots. Figure 10 shows an example of dead roots and diseased 

 areas of bark cut out on a treated tree, prior to painting. 



After completing the surgical treatment the treated areas should 

 be brushed clean of dirt and the roots inspected for any lesions that 

 may have been overlooked. All exposed wood surfaces should then be 

 painted with a good, durable pruning wound dressing. After this has 

 dried the excavation may be filled in partially or completely. If the 

 tree is not banked to stimulate the development of new roots, however, 

 it is a good idea to leave the root crown exposed indefinitely for aera- 



