56 EXPERIMENT STATION. [Jan. 



Influence of Water on Eel Wokms {Ileterodtra 

 radiclcola (Greef.), Miill.). 



BY G. E. STONE. 



In some subirrigation experiments with tomatoes, M^iieh 

 have been carried on here for some years in connection with 

 the blossom end rot of the fruit, observations of the roots have 

 shown that the presence of considerable water in the soil for 

 any length of time has an injurious effect on eel worms. Our 

 observations on the plots which were subirrigated, and which 

 contained more soil jnoisture below the surface than the top- 

 watered plants, showed that the eel worms were always rare, 

 in most cases entirely absent, whereas the roots of the top- 

 watered plants, growing in soil of a like character, showed nu- 

 merous galls. These observations were made on several crops 

 of tomatoes. 



Further experiments were made under our direction in the 

 Avinter of 190(3-07, in 8-inch boxes, by Mr. David Larsen, at 

 that time a student assistant, to demonstrate the injurious ef- 

 fects of water on eel worms. These experiments were con- 

 ducted as follows : — 



Two boxes were filled with soil contaminated with eel worms 

 and were i)lanted with cucumber seed, one box being arranged 

 in such a way as to allow a free passage of water through the 

 bottom, and set in a galvanized iron tray filled with water to 

 the depth of !/{> inches. By this means the bottom soil was 

 ke])t quite moist, while the surface remained comparatively dry. 

 The other box was surface watered, and the soil contained less 

 water. A uiiiiibcr of cucinnber seeds were planted in each box, 

 and everv few davs some of the plauts were removed fi-oui 

 the boxes and the roots examined. This experiment was con- 

 tinued for ten weeks, and in every case upon examination the 

 plants in Ihe box immersed in water showed roots free from 



