PEACH SCAB AND ITS CONTROL. 3 



1908) obtained promising results from the use of self -boiled lime- 

 sulphur for peach-scab control. The same author (1909) reported 

 that this fungicide satisfactorily controlled the disease without objec- 

 tionable foliage injury and recommended its use in commercial 

 orchards. These results have been confirmed by Scott and Ayres 

 (1910), Scott and Quaintance (1911), and other investigators. 



Thus, while peach scab has received a considerable amount of 

 attention from botanists and plant pathologists, the status of knowl- 

 edge of the disease has remained fragmentary and incomplete. No 

 attempt at a thoroughgoing study of the malady appears to have 

 been undertaken, previous work having been confined chiefiy to 

 descriptions of Claclosporium carpophilum and of the injuries which 

 it induces, to field observations, and to the empirical development 

 of control measures. Consequently, the etiology of the disease has 

 not been scientifically determined and the detailed life history of 

 the causal organism m relation to pathogenesis and to control meas- 

 sures has remained obscure. 



The purpose of the investigations reported in this bulletin has been 

 to further the understanding of the nature, cause, development, and 

 control of peach scab. Accordingly, the effort has been directed 

 along four correlated major lines of study, viz, (l)-the disease, (2) the 

 causal organism, (3) the detailed life history of the causal organism 

 in relation to pathogenesis, and (4) control measures. 



Studies of the relationships of peach scab to similar diseases of 

 other stone fruits have not been included in this problem, though 

 such investigations are now under way. Consequently, only peach 

 scab will be considered in this bulletin. 



THE DISEASE. 



GEOGRAPHIC DISTRIBUTION. 



In order to supplement the available pubHshed data concerning 

 the geographic distribution of peach scab in the United States, a 

 brief questionnaire was recently sent to the auth6rities ^ of each State 

 agricultural experiment station. The disease was reported from the 

 following States: Alabama, Arkansas, California, Colorado, Con- 

 necticut, Delaware, Florida, Georgia, Idaho, Illinois, Indiana, Iowa, 

 Kansas, Kentucky, Louisiana, Maryland, Massachusetts, Michigan, 

 Mississippi, Missouri, Nebraska, New Hampshire, New Jersey, New 

 York, North Carolina, Ohio, Oklahoma, Pennsylvania, Rhode Island, 

 South Carolina, Tennessee, Texas, Virginia, and West Virginia. 



In foreign countries, scab appears to occur practically wherever 

 the peach is grown intensively under normal conditions. However, 

 since peach production abroad is relatively of much less importance 



1 The writer wishes to make grateful acknowledgment of his indebtedness to all who cooperated in 

 compiling these data. 



