Report of State Board of Horticulture. 91 



that the disease can be satisfactorily controlled by the meth- 

 ods recommended in Bulletin No, 60 of the Oregon Experi- 

 ment Station. 



HISTORICAL. 



Apple tree anthracnose is a disease of the apple bark 

 which, so far as known, is confined to the Pacific Northwest. 

 Whether or not it has been communicated to the apple from 

 some of our native plants is not known. It seems first to 

 have been noticed about 1891 or 1892, and by 1893 or 1894 

 had attracted so much attention that upon request of the 

 Boards of Horticulture of Oregon and Washington, Dr. New- 

 ton B. Pierce, of the Division of Vegetable Pathology of the 

 United States Department of Agriculture, was detailed to 

 make an investigation of the trouble. Dr. Pierce spent some 

 time investigating conditions in the worst infested regions 

 and, although I am not aware that he published any detailed 

 report of his investigations, he evidently obtained an approxi- 

 mately accurate insight into the nature of the disease. In a 

 letter to the late Mr. J. M. Wallace, of Salem, Oregon, Dr. 

 Pierce wrote : "My work in Oregon and later at this labora- 

 tory, has demonstrated one thing beyond a reasonable doubt, 

 namely, that the apple canker so common in Oregon is a dis- 

 ease due to the action of a parasitic fungus. Inoculation ex- 

 periments here have reproduced the disease in a typical form 

 in perfectly healthy apple trees. * * * I have found the 

 various spore forms, as well as the tree which probably forms 

 the active host of the parasite in Oregon and Washington- 

 It has also become evident that the fungus works mostly 

 during the rainy season, and that infection of new trees may 

 take place in the fall and during most if not quite all winter. 

 This shows that trees must be treated before the rains begin 

 and often during the winter to prevent infection of new un- 

 affected tissues." 



In 1899, owing to repeated and urgent calls upon the Ex- 

 periment Station for information regarding this disease, the 

 writer, in the absence of a regular plant pathologist, started 

 an investigation, the results of which were published in the 

 Bulletin No. 60, above mentioned, and in which the disease 

 was definitely proved to be due to the attacks of a particular 



