BLACK ROOT-ROT OF TOBACCO |y;-j 



T. If, because of extreme acidity, lime is considered necessary, it should l)e 

 applied witii great caution and in small applications, always preceded l.y 

 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 rgot-rot. 



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

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



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

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

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

 those without cover crop. 



LirLt.ATUiUi ClTKH 



1. Briggs, L, J. The field treatment of toi)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. 19.5: 1-38. 1920. 



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



kinds of plants of liming an acid soil. R. I. Agr. Expt. St;i. Bui. 160: 

 4.07-446. 1914. 



4. Hutcheson, T. B. and D. J. Berger. Experiments witli bright tobacco 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 tobacco. 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. 1!)]6. 



7. Johnson, James and R. E. Hartman. Influence of soil environment on tlic 



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



8. Jones, J. P. Havana seed tobacco as influenced l)y 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. 



