S. DEPARTMENT OF AGRICULTURE. 



growing the crop on widely different soils, together with variations 

 in climatic conditions and methods of handling. The main prob- 

 lems confronting the growers in the different sections, therefore, 

 are not always the same. Any one disease may be much more serious 



UNITED STATES 



TOBACCO 



ACREAGE 



EACH DOT REPRESENTS 

 500 ACRES 



Fig. 1. — Map of the eastern half of the United States showing the tobacco-growing dis- 

 tricts. Intensive culture in relatively small districts is favorable to the accumulation 

 of plant diseases. 



in one section than in another or may not occur at all in some dis- 

 tricts, either because of conditions of environment or varietal dif- 

 ferences in resistance or due to the accident of introduction of the 

 parasite concerned. The control measures recommended therefore 

 may not apply equally well to all districts, but these details can not 

 be given full consideration in a brief treatise on the subject. 



