THE BROWN ROOT ROT OF TOBACCO AND OTHER PLANTS 



25 



Table 3. — Yields of crops on rotation plats located at Windsor, Conn., where 

 orown root rot did not develop as a factor in crop production 



[Acre yields in pounds except as otherwise stated] 



Crop in rotation 



Plat 



Yields of crop in rota- 

 tion 



Yields 

 of cured 

 tobacco 





1922 



1923 



(pounds), 

 1924 



Corn (yields in bushels) 



/No. 1 



80 

 132 



44 



77 



763 



\No. 11 



1.000 









106 



60.5 



881.5 









/No. 2 



600 

 1,600 



2,000 

 3,500 



900 





\No. 12. 







1, 125 











1, 100 2, 750 



1, 012. 5 









Beans (yields in bushels, shelled). 



/No. 3 



29 

 30 



28 

 25 



825 



\No. 13 



1,075 









29. 5 26. 5 



950 



Potatoes (yields in bushels) {no' 14 



Average . .. . 







323 



355 



237 

 197 



838 

 1,050 



339 



217 



944 





/No. 5 



\No. 15 





Tomatoes (yields in tons) -.---.. 



11.6 

 16.5 



22.8 

 20.4 



925 







Average . ... . ... ... 



14.1 



21.6 



1,025 





/No. 6 ... 





Fallow 







925 



\No. 16 





1.025 











Average . .... 







975 











Onions (yields in bushels).. .. . 



/No. 7 



120 

 160 



64 



1,050 



\No. 17 







78 l, V6$ 



Average ... . . _. 



140 



71 



1,044 





(No. 8 







480 ! 1, 400 

 500 1, 440 



1,138 





INo. 18 



1,000 



Average.. . . 



490 1,420 



1,069 





/No. 9 







740 



730 



1,440 

 1,420 



1,213 





\No. 19 



1,000 



Average . . 



735 1,430 



1, 106. 5 









Clover . ..... 



/No. 10 



\No. 20 



2, 200 3, 800 

 1, 800 ' 4, 000 



1,150 





975 











Average 



2.000 | 3,900 



1, 062. 5 





/No. 21 



\No. 22 





Tobacco (limed) 



720 

 700 



1,400 

 1,400 



1,100 





1,037 



Average _ 



710 1 400 



1, 068. 5 













DISCUSSION OF RESULTS 



The outstanding features of the brown root-rot problem have 

 been the failure to ascribe it to any definite causal agency and the 

 striking effect of the crop-rotation system upon the occurrence of the 

 malady. 



The problem as to whether brown root rot is of parasitic or non- 

 parasitic origin remains unsettled. The evidence pointing toward 

 the parasitic nature of the disease would be very convincing in the 

 absence of certain observations to the contrary. Though the writers 

 have not studied the literature carefully, there seems to be no fungus 



