Vi PREFACE 



At present, circumstances do not permit the plant doctor 

 to call in person or by letter to advise with every fruit- 

 grower regarding his many problems. No experiment sta- 

 tion can furnish bulletins that will answer the purpose in 

 every detail. And up to the present there have been no 

 American texts or reference books dealing wholly, and in 

 some detail, with the diseases of fruits. It is hoped that 

 this Manual will give to the fruit-grower such information 

 on fruit diseases as is available to date. The authors realize, 

 however, that the best possible book on fruit diseases cannot 

 entirely meet the situation. Possibly the day will come when 

 each neighborhood will be provided with its own plant doc- 

 tor; until this time the advice must remain qualified. 



It may appeal to the critic that many technical details are 

 included which will only confuse the grower. But the time 

 has come when the grower and the plant pathologist must 

 meet on an equal footing. No longer should the grower 

 refuse to understand the philosophy of his operations. Any 

 careful consideration of a disease involves the use of certain 

 terms not common in the farmer's vocabulary. The termi- 

 nology of the plant pathologist should be no more bewilder- 

 ing than that of the family physician or the veterinarian. 

 To assist in an understanding of the usage of certain terms 

 in the text, a glossary is appended. These terms may be 

 found in dictionaries, but differences in the shades of mean- 

 ing often lead to confusion. 



The grower is in the habit of grouping his troubles as well 

 as his labor and projects. In his own mind he classifies diseases 

 on the crop basis. Accordingly, only fruits are included in 

 this Manual. It is hoped that other crops may be the sub- 

 jects of similar manuals in the future. In seeking guidance 

 on any disease-control problem, the fruit-grower groups 

 fruit diseases according to the fruit. It has therefore seemed 

 best to discuss the diseases of a given fruit in one place. 

 The arrangement of the fruits in the text, that is, alphabet- 



