22 



CIRCULAR 8 5 3, U. S. DEPARTMENT OF AGRICULTURE 



tion and drying, except in sections where winter injury is likely to 

 occur. A further disinfection of the roots, as well as the soil, while 

 not necessary where a thorough surgical treatment is given, may be 

 obtained by pouring 2 to 3 gallons of a strong bordeaux mixture 

 (5-5-50) into the soil basin. Extensive surgical treatment of trees 

 sometimes leads to decay of the exposed wood at bases of trees despite 

 the use of a pruning wound compound. 



The recovery of trees that have lost a considerable proportion of 

 their root systems or have been partially girdled through root rot and 

 its treatment often can be expedited materially by banking the soil 

 around the bases to a height of several inches above the upper limit of 

 the partial girdle to stimulate the development of new roots from the 



t 



Figure 11. — New root system developed, on scalybark Australian pine by soil- 

 banking metbocl, following drastic surgical treatment for Clitocybe root 

 rot in which all roots but three small lateral ones on one side of the completely 

 girdled tree were removed. Photo made after washing away soil, less than 

 4^/2 years following treatment. 



callus formed at the margin of the living bark. Under favorable mois- 

 ture conditions new roots start developing within a few months, and 

 within a year or two should attain sufficient development to contribute 

 materially to the recovery of the tree {22). The efficac3 T of the soil- 

 banking method of inducing the development of new root systems on 

 trees is illustrated in figure 11. 



SUMMARY 



Clitocybe root rot, caused by the fungus Clitocybe tabescens, is re- 

 ported as a destructive disease of woody plants in the southeastern 

 United States. 



