BLACK-SPOT CANKER. 



In view of the large amount of injury to fruit-trees due to the work of 

 the black-spot canker (often termed anthracnose. black-spot canker, black- 

 spot apple-tree canker, and even sour-sap disease), and in view of the large 

 number of people coming into the Province, not conversant with this disease, 

 who will have more or less to do with tree fruits, it is thought expedient to 

 give to the public at this time, in the form of a concise practical bulletin, 

 a short treatise on our present knowledge of the history of the disease, its 

 habits and methods of prevention. By so doing it is hoped that systematic 

 and general work will be started this fall in order to prevent in so far as 

 possible with our present known methods, future damage by this pest of our 

 orchards. 



EXTENT OF DISEASE. 



This disease is to be found in British Columbia. Oregon. Idaho, and 

 Washington, but is not known in Eastern Canada or the Eastern and Middle 

 States at the present time. It is especially serious in the Coast districts, 

 where the rainfall is heavy and the humidity high in the latter part of the 

 year. Fungous diseases nourish best under moist atmospheric conditions, 

 so it is to be expected that this disease would be most prevalent in the 

 Coast districts. Damage due to this disease in British Columbia was reported 

 as early as 1901 by Mr. It. M. Palmer, but it is only a comparatively few 

 years since the cause of the injury was known, and we were able to determine 

 satisfactory and economical methods of prevention. In the United States 

 it seems to have been noticed first about 181)1 or 1892, for in 1894 it had 

 attracted so much attention that Dr. Newton B. Pierce, of the United States 

 Department of Agriculture, was detailed to make an investigation, and 

 determine, if possible, the cause of the injury. He proved it to be due to a 

 fungous disease. Recently Prof. W. H. Lawrence, of the Western Washing- 

 ton Experimental Station, issued to the public, in the form of a bulletin, 

 the results in detail of two years' study of this disease, and he has brought 

 forward a number of good points as to the nature of the disease and methods 

 of prevention, showing also that it attacked the fruit. There are other bark- 

 diseases to be found in British Columbia, such as black-rot canker (8i>tuicroi>- 

 sift inalorum), which might be mistaken for this disease, but these are due 

 to a different fungus and require different treatment. 



EXTENT OF INJURY. 



It is difficult to realize the damage done by this disease. Most of 

 the insect pests of our orchards come to us year after year, causing damage 

 to the various parts of the tree, and the results of their ravages are seldom 

 noticed the following year, unless in the form of a general weakening of 

 the vitality of the tree, which it is difficult sometimes to associate with the 

 attack of the insect. Black-spot canker (the name generally accepted by 

 fruit-growers in British Columbia to designate the disease) not only causes 

 injury by sapping the vitality of the tree by living parasitically on its life 



