ROOT GALLS, OR NEMATODES. 187 



measure to check the growth of other organisms. 

 In properly constructed houses, where the drip is 

 reduced to a minimum, little difficulty is ever 

 experienced from this disease. The trouble is, of 

 course, much more apt to be serious where the 

 plants are over-grown, and for this reason the 

 directions given in regard to proper time of plant- 

 ing and the handling of the plants should be 

 closely followed. 



Root Galls, or Nematodes. Although this 

 disease is caused by a minute parasitic worm, it is 

 classified with diseases for the reason that it affects 

 the entire plant and could not be properly treated 

 under the heading of insects. Plants badly in- 

 fested with nematodes are apt to show a dwarfed 

 growth, the leaves being small and the leaf stalks 

 and flower stalks short. This is what might be 

 expected from the fact that these minute parasites 

 attack the roots and through their action on them 

 cut off the food supply. The infested plants upon 

 being removed from the soil show on the rootlets 

 innumerable small nodules, varying in size from 

 a pin-head to a large pea. Although nematodes 

 are considered by some writers as a great menace 

 to violet growing, we have never seen any serious 

 injury produced by them. In fact, our experience 

 leads us to believe that nematodes, instead of 

 being actually injurious, are more apt to be bene- 

 ficial. We cannot speak of course of the effects 

 of nematodes where the soil has been allowed to 



