advises the use of land on which there have been no diseased 

 plants, together with seed taken from localities where the dis- 

 ease has not existed. 



j. S. Robinson^ foiuid that by spraying plants affected with 

 this blight three or four times in the summer with the Bordeaux 

 mixture, an increased yield of from 2.2 to 2.5 tons per acre 

 was obtained. 



EEL WORMS,— NEMATODES 

 (Heteradora radicicola, (Greef.) Miill.) 



One of the common troubles on indoor tomatoes is caused 

 by nematodes, — small worms which inhabit the soil. They gain 

 entrance to the young roots, where a part of their development 

 takes place. The presence of these minute worms in the tissue 

 of the roots causes a reaction on the part of the cells, resulting 

 in the formation of galls. On tomato roots many galls are 

 formed, which cut off the water supply and cause more or less 

 injury to the crop. 



These worms also attack cucumbers and melons, and some- 

 times lettuce ; in the greenhouse melons being especially sus- 

 ceptible. Since tomato plants are more hardy than either 

 cucumbers or melons, they naturally suffer less from the effects 

 of eel worms. 



Eel worms are very susceptible to treatment by desiccation, 

 freezing, excess of water, and high temperatures, and the 

 methods of treatment are based upon our knowledge of the 

 influence of these factors upon the organisms. Desiccation, or 

 drying the soil, has been employed in Europe on held crops and 

 is very satisfactory when applied on a small scale in a green- 

 house, but with deep benches we did not find the method effective. 

 Removing the soil and replacing it with new, or freezing it, is 

 quite effective, and the so-called catch-crop method has proved 

 successful in some instances. This method consists in planting 

 some crop like mustard or rape before the regular crop is planted, 

 and when the galls are well formed the crop is dug up and the 

 roots exposed to the drying action of the sun. which kills the 

 worms. By this method the females are captured and destroyed 

 at the most advantageous time. We have experimented with 

 the catch-crop method in the greenhouse and found at times that 

 it was fairly successful, especially when more than one catch- 

 crop was planted. 



A variation in the catch-crop method, consisting in sowing 

 some crop susceptible to eel worm infection at the same time 



1. Md. Agr. Exp. Sta., Bui. No. 54, 1898, p. 122. 



