J-o.c&^ S^4 



UNITED STATES DEPARTMENT OF AGRICULTURE 



s\j9^^-^ru 



BULLETIN No. 368 



Contribution from the Bureau of Plant Industry 

 WM. A. TAYLOR, Chief 



Washington, D. C. 



PROFESSIONAL PAPER 



March 6, 1916 



BROWN-ROT OF PRUNES AND CHERRIES IN THE 

 PACIFIC NORTHWEST. 



By Charles Brooks and D. F. Fisher, Office of Fruit-Disease Investigations. 



CONTENTS. 



Introduction 1 



Blossom infection of prunes 2 



Spraying experiments 4 



Fruit rot of prunes 5 



Page. 



Summary and conclusion for prunes 8 



Blossom infection of cherries 9 



Brown-rot of cherries 9 



Summary and conclusion for cherries 10 



INTRODUCTION. 



For several years the growers of the lower Columbia and Willam- 

 ette Valleys have had severe losses of their prunes and cherries. 

 Among the causes have been a failure of the trees to set a full crop 

 and a lack of keeping quality in the harvested fruit due to brown-rot. 

 Occasional midsummer outbreaks of brown-rot have also occurred. 



In the spring of 1914 Mr. M. B. Waite, Pathologist in Charge of 

 Fruit-Disease Investigations, examined some diseased prune blossoms 

 from Vancouver, Wash,, and was in correspondence with the growers 

 concerning the cause of the prune trouble. He has furnished the 

 following manuscript note covering these investigations : 



With a letter dated April 18, 1914, from Mr. Chapin A. Mills, Vancouver, Clarke 

 County, Wash., addressed to the Department of Agriculture, specimens of spurs and 

 twigs of the Italian prune (Prunus domestica), with dead and dying blossoms, were 

 received, with an inquiry as to the cause and remedy for the bad condition of the 

 blossoms, the dropping of the bloom and young fruit, and the widespread failure of 

 the crop to "set" or hold its fruit. A few days later a similar set of specimens was 

 received from the same district, and a number of inquiries, without specimens, reached 

 us from Washington, Oregon, and California, including the Sacramento and Santa 

 Clara Valleys, as to the cause of the failure of the prunes to set their fruit. 



Note. — This bulletin is intended particularly for the benefit of prune and cherry growers of western 

 Washington and Oregon, but is of interest to growers of these fruits in other sections of the United States. 

 Itis also of scientific interest to plant pathologists in general. 

 "—Bull. 368—16 



