CH. YIII.] THE DISEASES OF PLAKTS. 287 



Pruning has a povrerful influence in preventing 

 the occuiTence of the canker. I remember a standard 

 russet apple tree, of not more than twenty years' 

 growth, with a redundancy of ill-arranged branches, 

 that was excessively attacked by this disease. I 

 had two of its three main branches and the laterals 

 of that remaining carefully thinned ; all the in- 

 fected parts being at the same time removed. The 

 result was a total cm'e. The branches were annually 

 regulated, and for sLx years the disease never re- 

 appeared. At the end of that time the tree had to be 

 removed, as the gi'omid it stood upon was required 

 for another pm'pose. John Williams, Esq. of Pit- 

 maston, from long experience, concludes that the 

 golden pippin and other apples may be presented 

 from this disease, by pnining away every year that 

 part of each shoot which is not perfectly ripened. 

 By pui-suing this method for sLx years, he brought a 

 dwarf golden pippin tree to be as ^dgorous and as 

 free from canker as any new variety^. 



All these facts unite in assuring us that the 

 canker arises from the tree's weakness, from a de- 

 ficiency in its \ital energ}', and consequent inability 

 to imbibe and elaborate the nourishment necessary to 

 sustain its frame in "sdgoui', and much less to supply 

 the healthy developement of new parts. It matters 

 not whether its energ}' be broken down by an unna- 

 tural rapidity of growth, by a disproportioned excess 

 ^ Trans. London Horticultural Society, vi. Art. 61. 



