THE MONTHLY BULLETIN. 



43 



face. This explains why tlie disease lurks beyond the cambium layer 

 and why removal may re(|uire deeper cutting than has been supposed. 



THE CURE. 



As yet Ave know no cure for pear blight except the knife. Every 

 semblance of disease must be excised. This may rob a tree of large 

 branches, great roots and a more or less deep layer from bark toward 

 the ])ith of the tree. Figure 10 shows a tree thus excoriated. IMost 

 iinpoi'laiit, the cutting instrument must be thoroughly disinfected after 



Fig. 11. — Tree in whicli many of the roots were 

 cut away in treating for pear blight, it now 

 being ancliored by a post, as shown in tlie illus- 

 tration. (Plioto by Ray R. Roberts.) 



each separate cut. Corrosive sublimate (bichloride of mercury) 1 to 

 1000, is the best disinfectant. 



In Oregon I saw trees where the roots had been so cut away that a 

 post was set beside the trees to which it was bolted to serve as an 

 anchor — Figure 11. In other cases suckers from healthy or young 

 pear trees set close beside the diseased trees w^ere grafted into the tree 

 along the trunk to replace the function of excised roots of the tree — 

 Figure 12. Yet so valualile is the pear that all this care and expense 

 paid well. 



Professor F. C. Reimer of the Oregon Experiment Station, a second 

 Waite on pear blight diseases, urges Japan stock for pears rather than 

 the French stock, the one generally used. He is a firm believer in re- 



