UOd.] PUBLIC DOCUMENT — Ko. U. 5^ 



6rops showed galls on the roots in both boxesy the limed boxes 

 sometimes showing a less and sometimes a greater number of 

 galls on the roots than the box treated with saccharate of lime^ 



In another experiment, started July, 1904, made with con^ 

 taminated soil in three boxes 8 by 8 by 8 inches, we obtained 

 the following results : — 



Box No. 1, contaminated with eel worms, did not receive any 

 treatment. 



Box ISTo. 2, similarly contaminated with eel worms, was 

 treated with 400 grams of lime thoroughly mixed with the soil. 



Box 'No. 3, similarly contaminated, was treated with 15 cubic 

 centimeters of formalin, which was poured into a hole in the 

 soil 4 or 5 inches deep, the hole being covered over to allow the 

 formalin vapor to permeate the soil. After treatment the boxes 

 were planted wath melon seeds, or those of some other very sus- 

 ceptible plant, and the roots examined for galls. Only three 

 crops were grown in these boxes and the galls were present on 

 the roots of the plants in each case. From these experiments 

 it is evident to us that lime and formalin have little or no eifect 

 on eel worms in the soil ; at least in the proportions which we 

 used. The amount of lime used, however, was considerable in 

 this last experiment, and when thoroughly incorporated with the 

 soil was sufficient to give it quite a little color. 



While there are many chemicals which will kill eel worms, 

 it would not be advisable to use them, since they will cause 

 injury to both plants and soil. In some of our former experi- 

 ments with eel worms, described in Bulletin No. 55, the forma- 

 lin method was tested on free-moving forms of the worms, with 

 the result that they succumbed in a few minutes when subjected 

 to the vapor, but we were not successful in applying formalin to 

 soil containing growing plants without injuring them. Of late 

 years formalin has been recommended as a remedy for eel 

 worms on violets. This is used by applying it to holes made 

 in the soil where the plants are growing. The formalin being 

 volatile, the gas penetrates the soil and is said to kill the worms. 

 Our experiments with it would not seem to warrant the use of 

 this method of treatment, as formalin is injurious to plants, 

 and there is reason to believe that it would not affect in the 

 least the eggs of eel worms, which are fairly well protected by 



