PLATE 7 
• A.—-Segregated rootrot area 16 days after treatment with formaldehyde. No plants 
outside the original area had died since treatment. 
B. —Control area of approximately the same original size; the disease had advanced 
61 cm. in 16 days. 
C. —The rootrot area shown in Plate 7, A, 60 days after treatment. No further 
infection had been observed. 
D. —The control area shown in Plate 7, B, 60 days after treatment of the infected 
spot in A. The disease had increased the diameter of the circle by about 3 meters. 
In order to make it more comparable to the treated area, a dike was thrown up about 
the stakes which were placed to define the limits of the disease on August 3. 
