BLACK ROOT-ROT OF TOBACCO 



13^ 



7. If, because of extreme acidity, lime is considered necessary, it should be 

 applied with great caution and in small applications, always preceded by 

 determinations of soil reaction in order to avoid approaching too closely the 

 danger point of pH 5.9. 



8. The use of timothy cover-crop was found to have no significant effect 

 on the prevalence of black root-rot. 



9. The use of timothy cover-crop reduced the yield of tobacco for tiiree 

 consecutive years. This effect was associated with brown root-rot. 



10. When timothy cover crop was omitted for one year, the depressing 

 effect of timothy quickly disappeared and was replaced by a beneficial effect. 

 In these experiments the yield on plots so treated exceeded by 17 per cent 

 those without cover crop. 



laxEUATuui: Cited 



1. Briggs, L. J. The field treatment of tol)acco root-rot. U. S. Dept. Agr. 



Bur. Plant Indus. Circ. 7: 5-8. 1908. 



2. Chapman, G. H. Tobacco investigations, progress report. Mass. Agr. 



Expt. Sta. Bui. 195: 1-38. 1920. 



3. Hartwell, B. L. and S. C. Damon. The comparative effect on different 



kinds of ])lants of liming an acid soil. R. I. Agr. Expt. Sta. Bui. 160: 

 407-446. 1914. 



4. Hutcheson, T. B. and D. J. Berger. Experiments with briglit toliacco and 



other crops grown on bright tobacco farms. Va. Agr. Expt. Sta. Bui. 

 233: 3-19. 1923. 



5. Jenkins, E. H. and G. P. Clinton. Root-rot of tol)acco. Conn. Agr. Expt. 



Sta. Bui. of Immediate Information 4: 1-11. 1906. 



6. Johnson, James. Host plants of Thielavia basicola. Jour. Agr. Res. 7: 



289-300. 1916. 



7. Jolinson, James and R. E. Hartman. Influence of soil environment on the 



root-rot of tobacco. Jour. Agr. Res. 17= 41-86. 1919. 



8. Jones, J. P. Havana seed tobacco as influenced by timothy cover crop. 



Mass. Agr. Expt. Sta. Circ. 73: 1-3. 1925. 



9. McCall, A. G. Fertilizers for Maryland soils. Md. Agr. Expt. Sta*. Bui. 



247: 117-151. 1922. 



