FUNGI AND PARASITES 



191 



to a tree it will prove fatal, about an ounce at a 

 place on three sides of the crown, in two applica- 

 tions ten days apart being efficacious. These solu- 

 tions sell wholesale from ten cents to one dollar a 

 gallon. 



NEMATODES. 



(Heterodera Radicola.) 



The nematode is a microscopic, parasitic eelworm. 

 It is generally found where the ground does not 

 freeze deep, working upon the roots of many vege- 

 tables, cotton, grains, ornamental, orchard and 

 forest trees, the soft, porous roots of figs affording 

 excellent food. In sandy soil it sometimes goes 

 down eight or ten inches, but in heavy loams four 

 inches is the ordinary limit. Root enlargements 

 usually first indicate its presence, these sometimes 

 being mistaken for nodules on legumes, and are 

 often so uniform in size and so regular in dis- 

 tances apart as to remind one of beads threaded on 

 strings; but occasionally a single swelling becomes 

 six inches in diameter. 



The injury is done by interfering with the flow 

 of sap — the circulatory life fluid of the tree. The 

 cellular fibrous system becoming infested its con- 

 tinuity is destroyed and roots swell at points of in- 

 festation in vain efforts to provide adequate cells 

 for normal circulation. 



Numerous experiments have been made for the 

 purpose of discovering means for controlling this 



