PLATE 19 
Fig. A.—Part of a field infected with Thielavia basicola in foreground, with newer 
soil planted to tobacco in the background, illustrating the marked pathogenic 
powers of this organism. 
Fig. B.—A tobacco plant showing diseased roots from infected soil. 
Fig. C.—Healthy roots from uninfected soil of a semiresistant type of tobacco (Con¬ 
necticut Havana). Figures B and C show the relative growth of plants and amount 
of root system after equal care in removing roots from the soil. 
