«*V« 



UNITED STATES DEPARTMENT OF AGRICULTURE 



In Cooperation with the 



College of Agriculture, University of Wisconsin 



DEPARTMENT BULLETIN No. 1256 



Washington, D. C. 



October 13, 1924 



TOBACCO DISEASES AND THEIR CONTROL 



By 



JAMES JOHNSON, Agent, Office of Tobacco Investigations 



Bureau of Plant Industry, and Professor of Horticulture 



College of Agriculture, University of Wisconsin 



CONTENTS 



Page 



Introduction 1 



The Nature of Plant Diseases 3 



Losses from Disease 3 



The Plant Bed as a Source of Infection 4 



Plant-Bed Sanitation . ' 4 



The Sterilization of Soil for Plant Beds 5 



Stem or Stalk Diseases 7 



Root Diseases 18 



Leaf Diseases 25 



Injuries Due to Physical Agencies 41 



Unimportant or Rare Diseases Not Otherwise Classified 41 



Damage in Curing and Fermentation 43 



Diseases of Tobacco in Foreign Countries 48 



Bibliography 50 



WASHINGTON 



GOVERNMENT PRINTING OFFICE 



1924 



