UNITED STATES DEPARTMENT OF AGRICULTURE 



BULLETIN No. 543 



Contribution from the Bureau of Plant Industry 

 WM. A. TAYLOR, Chief 



j^r^RJl. 



Washington, D. C. 



W 



August 8, 1917 



CONTROL OF PEACH BACTERIAL SPOT IN 

 SOUTHERN ORCHARDS. 



By John W. Roberts, Pathologist, Fruit-Disease Investigations. 



CONTENTS. 



Introduction 1 



Description of the disease 2 



Cause of the disease 3 



Page. 



Varietal susceptibility 3 



Control experiments 4 



Summary and conclusions 7 



INTRODUCTION. I 



In most of the peach-growing sections of the eastern half of the 

 United States the disease commonly called bacterial spot, or bacteri- 

 osis, is becoming increasingly important, especially in the more 

 southerly sections. It is impossible to give any estimate of the 

 damage which it causes annually, (1) because it is mainly a disease 

 of the foliage and (2) because of its great seasonal variation. It has 

 been reported as occurring in practically the whole of the eastern 

 United States, including Massachusetts, Connecticut, New Jersey, 

 Delaware, Maryland, Pennsylvania, Michigan, Illinois, Indiana, Ohio, 

 Kentucky, Tennessee, Virginia, North Carolina, South Carolina, 

 Georgia, Alabama, Arkansas, Missouri, Nebraska, and Texas. As 

 a rule, it is most serious in the more southerly peach-growing sec- 

 tions, but during recent years many specimens from farther north 

 were sent to the Bureau of Plant Industry for identification and 

 for suggestions as to control measures. During the years 1914 and 

 1915 the writer found the disease to be serious in the Ozark region of 

 Arkansas, being surpassed in destructiveness only by scab and brown- 

 rot. 



Note. — This bulletin is of interest to peach growers in the eastern half of the United States and particu- 

 larly those of the more southerly parts of this section. It is also of interest to plant pathologists. 4 T' : '-~<w r 

 84987°— Bull. 543 17 *A. -«-j|~..; 





