Bui. 818, U. S. Dept. of Agriculture. 



Plate III. 



WmmmWm ^ 



fit 



B 



Fig. I.— Roots and Stems of Tomato Plants Taken from 8-!nch Pots of 

 Treated and Untreated Infested Soil, Shown in Plate II, Figures I and 2. 



A, Large disease-free root systems of plants grown in a pot treated -with S.OCOc. c. of boiling water (98° C.) 

 (natural size); B, smaller root systems of plants grown in a pot receiving 1,000 c. e. of boilng water 

 (natmral size). Note occasional nematode gaJls on lower part of roots and a smaU number of dark 

 Rhizoctonia root lesions. C, Roots and stem of plant from check pot (enlarged 2i times). Kote large 

 galls on stem and old part of root system and small galls on younger, newly formed root system. It 

 should also be noted that the lower part of the taproot and practically aU of the secondary roots have 

 been destroyed by the pathogenes. 



Fig. 2.— Bench Sections No. 3 (Left) Treated with 17,000 c. c. .3.6 Gallons) 

 Per Cubic Foot of Soil of Boiling Water (.98' C.) and No. 4 (.Right) Un- 

 treated Check, Experiment Series I. 



Note the differences as to number, size, and vigor of plants in the two sections. Pronomieed differences 

 in the root systems of the lettuce plants taken from these sections are shown in Plate IV, f gure 1. 



