SYNOPSIS. 

 Part I. 



Page 

 Nematode Worms in the greenhouse. (Introductory.) 6 

 What Nematodes are. 8 

 Symptoms of Nematode injuries. 8 

 Galls Due to other causes than Nematodes. (Club Root, Legum- 

 inous Tubercles, Insects.) lo 

 Nature of the galls produced by lieterodera radicola, and the harmful 



results occurring from them. Secondary effects. ii,i5 

 Description of free-living Nematodes. i6 

 Description of the Parasitic, gall-forming Nematode, Heterodera radi- 

 cola, Greef. 19 



a. Early Life. 19 



b. Development of male. 20 



c. Development of female. 22 

 Recapitulation of the life history of Heterodera and the formation of 



its galls. 23 



Historical Review of economic work in gall-forming Nematodes. 24 



Identity of our species. 26 



Part II. 



Nature of the problem in controlling Nematodes. 28 



Plants which are subject to Nematodes. 29 



Amount of damage caused by Nematodes. 30 

 Review of the various remedies which have been applied for Nematode 



repression. 32 



a. Treatment by chemicals. 32 



b. Desiccation method. 35 



c. The Halle or Catch-crop method of destroying Nematodes. 36 

 Effects of chemicals upon Nematodes. 37 

 Sterilizing or heating the soil the most effectual and practical method 



of exterminating Nematodes in the greenhouse. 44 



Amount of heat necessary to kill Nematodes and their eggs. 45 



Methods of sterilizing the soil. 48 



Cost of sterilization. 57 



Effects of heating the soil on the growth of the crop. 58 



Effects of heating the soil upon other greenliouse pests. 59 



Relation of Nematodes to their environment. 60 



Resum^. 64 



Explanation of plates. 68 



