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JOURNAL OF ACRICET1ML RESEARCH 



Vol. XX Washington, D. C, January 3, 1921 No. 7 



FUSARIUM-WILT OF TOBACCO 1 



By James Johnson 



Associate Professor of Horticulture, University of Wisconsin, and Agent, Office of 

 Tobacco Investigations, Bureau ■ of Plant Industry, United States Department of 

 Agriculture 



INTRODUCTION 



During the summer of 191 6 the writer's attention was called to a wilt 

 disease of tobacco occurring near Benedict, Charles Co., Md. The dis- 

 ease occurred on the Maryland Broadleaf variety of tobacco, which was 

 nearing maturity, and showed all the appearances of a typical wilt dis- 

 ease. Plants in all stages of wilting were found, from those showing the 

 first signs of infection to those in which all the tissues of the plant were 

 dead. When the stalks or midribs of the leaves were cut, the fibro- 

 vascular bundles were found to have a distinctly brown to black color in 

 place of the normal white. It was at first suspected that the bacterial 

 wilt due to Bacillus solanacearum Erw. Smith had been introduced into 

 the Maryland tobacco fields. Although the general symptoms of the 

 disease were very similar to those of bacterial wilt, the absence of bacterial 

 ooze, the uniform occurrence of Fusarium on plated out material, the 

 absence of vessels filled with bacteria, and the presence of fungus strands 

 in the vessels gave strong evidence that bacteria were not concerned. 

 Considerable difficulty was at first encountered in getting good infection 

 with the Fusarium isolated. When artificial infection was finally secured, 

 however, further study of this disease became of special interest, since no 

 Fusarium-wilt disease of tobacco has apparently been proved to exist, 

 although, as will be shown, in one case it seemingly had been reported 

 erroneously, and in another case a Fusarium disease, apparently not a 

 wilt, has been described. The present paper is intended primarily to 

 establish the occurrence of a Fusarium-wilt of tobacco, with a description 

 of the causal organism and a discussion of certain matters bearing on the 

 control of the disease under practical conditions. 



1 Cooperative investigations of the Office of Tobacco Investigations, Bureau of Plant Industry, United 

 States Department of Agriculture, and the Wisconsin Agricultural Experiment Station. 



Published with the permission of the Director of the Wisconsin Agricultural Experiment Station. 



Journal of Agricultural Research, Vol. XX, No. 7 



Washington, D.C. Jan. 3, 1921 



we Key No. G-214 



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