APPLE DISEASES 



441 



and has been reported doubtfully from 

 Idaho. It has not been recorded in Cali- 

 fornia to our knowledge, though it is not 

 improbable that it occurs in the northern 

 counties, since it is common in Jackson 

 and Josephine counties in Oregon. It is 

 most serious in those sections having 

 considerable rainfall west of the Cascade 

 mountains. It is rarely a serious disease 

 In the fruit sections east of the Cas- 

 cade mountains. It has been reported 

 once from Nebraska. 



Life History Studies 



The apple tree anthracnose has prob- 

 ably occurred in the Northwest for many 

 years. It began to attract attention as 

 an orchard trouble during the period 

 from 1891 to 1893. The serious nature of 

 the disease was realized at that time and 

 through the efforts of the Boards of Horti- 

 culture of Oregon and Washington, the 

 United States Department of Agriculture 

 sent Professor M. B. Pierce to investigate 

 this trouble. He made considerable study 

 of this disease in both Oregon and Wash- 

 ington but made no official report. The 

 records of his work are contained in ex- 

 tracts of letters published in the Second 

 Biennial Report of the Washington State 

 Board of Horticulture and in the Fifth 

 Biennial Report of the State Horticul- 

 tural Board of Oregon. It is evident from 

 these reports that Pierce recognized the 

 true nature of the disease and probably 

 isolated the causal fungus and studied it 

 in culture and produced the disease 

 by inoculation. 



The first published work regarding this 

 disease was made by Professor A. B. Cord- 

 ley (1900) of the Oregon Experiment Sta- 

 tion, who published a full statement of 

 the life history of the disease and a de- 

 scription of the organism causing it, to- 

 gether with the results of inoculation 

 work. He named the fungus Gloeosporium 

 malicorticis. At about the same time Dr. 

 C. H. Peck described the same fungus un- 

 der the name of Macrophoma curvispora. 

 The writer has used the former name 

 upon the grounds that Cordley places the 

 fungus more nearly in the proper genus, 

 • and since the name which he proposed 



has of late come into more general use. 

 The disease was studied in Washington 

 by Lawrence (1904) who verified all of 

 Cordley's work and also records many 

 interesting and important biological 

 phases of the disease. He was the first 

 to publish an account of the disease as 

 a cause of a rot of stored fruit. 



In 1906. on account of the fact that 

 many points regarding the life history of 

 the disease had not been thoroughly work- 

 ed out, the Oregon Experiment Station un- 

 dertook a detailed investigation of the life 

 history and control of this disease. 



Mr. C. C. Cate. a graduate student, made 

 a thorough orchard survey of the disease 

 in various parts of that state in an effort 

 to determine whether any information 

 could be obtained regarding the suscep- 

 tibility of varieties, and whether the con- 

 ditions of the soil had anything to do 

 with the degree of susceptibility. He 

 found very little evidence to indicate that 

 soil conditions had any influence upon 

 the abundance of the trouble. The fol- 

 lowing quotation (Cate, 1908) indicates 

 the results of the investigations regarding 

 the susceptibility of varieties: 



"From investigations made during the 

 past summer, it was found that Anthrac- 

 nose attacks practically all varieties of 

 apples, although some are more sus- 

 ceptible than others. Those most sus- 

 ceptible are Baldwins, Spitz and Jona- 

 thans; next are Newtowns, Greening, 

 Gravenstein and most of the summer vari- 

 eties, while those attacked only slightly 

 are the Ben Davis, Northern Spy, Wine- 

 sap and Blacktwig. No varieties seem 

 to be entirely immune and occasionally 

 some of the least susceptible varieties are 

 nearly or entirely ruined by the disease. 

 In the varieties like Baldwin and Spitz, 

 the cankers are of all sizes and most of 

 them extend very deep and hence greater 

 damage is done, while on the Ben Davis 

 cankers or wounds are smaller and more 

 superficial, hence very little damage is 

 done to trees of this nature." 



The writer began the study of this 

 disease in the summer of 1909, which has 

 been continued as time would permit, 

 since that date. In the course of this 



