CARBON DISULFIDE EMULSION 7 



TABLE 4. — Comparison of Combinations of Carbon Disulfide Emulsion 

 AND Soil Fungicides with Steam for Combating the Root-Knot 



Nematode. 



(Fall Crop of Tomatoes, 1931. Commercial Greenhouse) 



Carbon Disulfide Emulsion 



Steam Pan 1 —50 



With 1 gallon With 1 gallon 

 Formaldehyde Acetic Acid 



Yield of 100 plants pounds 203 244 188 



Root infestation per cent 



Apparently none 100 



Slight 



Severe 



Spring of 1932. — This test was conducted to determine the influence of differ- 

 ent rates of application of diluted carbon disulfide emulsion and to compare 

 chemical with steam treatment of the soil in the control of the nematode. The 

 roots of the previous fall crop were dug January 18, 1932, and the soil treatments 

 were applied on February 15. Carbon disulfide emulsion, diluted at the rate of 

 1 gallon to 50 gallons of water, was used at different rates of application, and the 

 treated beds were set to tomatoes February 22, 1932. Records of root infestation 

 were taken on July 25. The best control of the root-knot nematode was obtained 

 in the steamed plot where but 3.7 per cent of the roots were found to be infested, 

 compared with 21.42 per cent in the plot receiving 1.4 gallons and 33.32 per cent 

 in the plot receiving 1 gallon of diluted carbon disulfide emulsion per square 

 foot (Table 5). In spite of these significant differences in control, the yields 

 offered only a slight and inconsistent contrast. Since a rate of 1.4 gallons per 

 square foot would insure a more thorough wetting and greater penetration than 1 

 gallon, it is inferred that thoroughness of application is an important factor 

 contributing toward the successful control of the pest. 



TABLE 5. — Influence of Rate of Application of Carbon Disulfide 

 Emulsion on the Control of the Root-Knot Nematode, as Com- 

 pared with Steam. 



(Spring Crop of Tomatoes. 1932. Commercial Greenhouse) 



Steam Pan Carbon Disulfide Emulsion 1 — 50 

 1.4 gallons 1 gallon 



per square foot per square foot 



Root infestation per cent 



Apparently none 96.29 



Slight 2.47 



Moderate 



Severe 1.23 



Total infestation 3.70 



Yield of 100 plants pounds 668 



Experiments at the Field Station 



Spring of 1931. — Single and double applications of carbon disulfide emulsion 

 were compared fcr their control of the root-knot nematode. A 1-50 concentration 

 of carbon disulfide emulsion was used. The basal root clumps of the previous 

 planting were dug out on January 30, 1931. Treatments at the rate of 1 gallon 

 to each square foot of bed were made on February 12 and 19. The treated beds 

 were set to tomatoes on February 26. The roots were examined on August 6 



