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PEAR GROWING IN CALIFORNIA. 



Some very careful experiments have been conducted at Watsonville bj' 

 W, H. Volck, County Horticultural Commissioner of Santa Cruz 

 County,* which show that in the case of the apple these materials, 

 instead of protecting the cuts against wood rot, make conditions ideal 

 for the development of the fungus {Polystictus sp.)- Treating of this 

 subject of wound protection against wood rot in the article referred to in 

 the footnote, Mr. Volck stated as follows: "Formerly such treatment 



Fig. 123. 



Undesirable stub left in 

 pruning. 



Fig. 123o. Desirable cut made in removing 

 stub shown in Fig. 123. (After W. H. Volck.) 



consisted in the application of some kind of paint to the entire surface 

 of the cut. This painting appeared to be the proper thing in that the cut 

 could be sealed, thus presumably protecting it from infection. In this 

 it failed, however, owing to the fact that the sap pressure behind the 

 painted surface is nearly always sufficient to rupture it. At the same 

 time the paint retains enough of the sap to keep the wood saturated 

 and provides an excellent medium for the growth of wood-rot fungus. 

 It so happens that the most impervious paints have proved to be the 

 poorest protection against wood-rot infection." The method of treat- 

 ment that has proven satisfactory in Mr. Volck 's experiment is outlined 

 briefly as follows: First of all the cut must be made properly, as no 

 amount of treatment will prevent the rotting of a stub. The smooth 

 close-in cut, as soon as it is made, is covered over on the edge or bark 

 layer with a thick coating of asphaltum-paraffine grafting wax, to pre- 

 vent the drying out of the cut surface, and the dying of the bark, giving 

 it a chance to begin the healing process immediately. Most of the wood 

 is left uncovered, and driven full of copper nails or tacks which are 



*W. H. Volck— Article Monthly Bulletin, State Commission of Horticulture, Vol. 

 VI, Nos. 3 and 4, "Pruning Fruit Trees with Special Reference to the Apple." 



96 



