TIIK UnVllII.Y BULLETIN. 89 



an excellent medium for the growth of the wood rot fungus 4 . It so 

 happens that the most impervious paints have proved to be the poorest 

 protect inn against wood rot infection. 



In the method described in this paper, the greater portion of the cut 

 is left uncoated in order to avoid these stagnant sap accumulations. 

 The Bordeaux whitewash application is pervious and .so does not retain 

 the sap. 



The use of copper nails is the outcome of a long series of experiments 

 in the effort to find some disinfectant which would remain effective for 

 a very long time. 6 Sufficient time has not ye1 elapsed to demonstrate 

 what the ultimate outcome of this method will be, but it looks very 

 promising at present. We have opened up .some of the older wounds, 

 so treated, and found no wood rot. At the same time the bark cover 

 over the surface of the wound was developing at a satisfactory rate. 



Another drawback to painting has been the fact that the paints fre- 

 quently prove injurious to the bark tissue, killing it back, thus greatly 

 delaying, and in many instances absolutely preventing the healing of 

 the wound. In one instance a red-lead paint induced serious wood rot 

 the very season it was applied. 



As a protection to exposed bark tissue the asphaltum wax is vastly 

 superior to any other material which has come to my notice. This wax 

 causes no injury to the bark tissue but on the contrary, growth is 

 apparently stimulated by its presence. From these considerations it 

 might be a good practice to keep the edge of the overgrowing bark 

 continually coated with the wax, by an application every year. 



Referring back to pruning 1 wish to add a few words regarding the 

 development of the so-called "'suckers" or " watersprouts " into fruit 

 spurs. If these suckers are kept pruned back, quite short, every year, 

 they will throw out laterals and produce blossom buds. In the experi- 

 mental plot we now have many fruit spurs which have been developed 

 in this way. It is thus possible to maintain a bearing surface on all the 

 large limbs, and near the ground. The shade afforded by these spurs 

 will largely prevent sun burning and so permit the maintenance of a 

 very open head. Of course, these spurs will eventually outgrow their 

 usefulness and will have to be replaced by new spurs. This thinning 

 out of the older spurs should be done before they have attained a size 

 sufficient to give trouble in treating the cuts. 



These sucker spurs are probably not the thing in a region where pear 

 blight is a serious disease, but they are certainly very promising under 

 California coast conditions. 



•When I noticed this tendency of paints to induce wound-rot I advised the growers 

 to discontinue the use of any paint on limb stubs and saw cuts. Many growers have 

 followed this advice with good results. Very few such untreated cuts have rotted 

 ami so far as I have observed, none at all where the cut was properly made. The 

 fact that these untreated cuts may rot in time is admitted and is the reason for the 

 attempt at permanent disinfection as described in the text. 



•The heads of the nails are indicated resting on the surface of the cut. In time 

 these projecting nail heads may give trouble by being forced into the overgrowing 

 bark, in which case they should be driven down with a nail-set. 



