428 ALFALFA FARMING IN AMERICA. 



heavier than air, sinks downward and comes to fill every cham- 

 ber and gallery, destroying all the occupants. 



It must be remembered that carbon bisulphide is as explosive 

 as gasoline and must be used with equal care. 



Conclusions. The conclusions of Prof. Headlee as 

 to the proper way to combat these insect enemies of 

 alfalfa are as follows: 



When we call to mind that the grasshopper passes the winter 

 in the soil in the egg stage, the web .worm, army worm and cut- 

 worms remain in the soil over winter as larvae, the fall army- 

 worm as a pupa, that the blister-beetles are dependent upon a 

 supply of grasshopper eggs for food during one necessary stage, it 

 is plain that thoroughly stirring the soil with a disk-harrow 

 (preferably the spike-tooth kind) just after the frost is out of the 

 ground and before the plants begin to grow, or, better still, in the 

 late fall just before the ground freezes, if such a proceeding 

 would not injure the plants, will go far toward controlling the in- 

 sects enumerated. During the summer, when these insects are 

 in the field or when the alfalfa is attacked by clover hay worms, 

 leaf-hoppers, mound-building prairie ants or pocket gophers, the 

 grower must resort to measures especially fitted to destroy the 

 enemy in question. 



To this I would add that in the eastern states 

 insect enemies are much less in evidence in alfalfa 

 fields, owing probably to the cold, wet winters, and 

 the pocket gopher has not yet been introduced, 

 though he is probably on his way. Woodchucks or 

 groundhogs are a pest in eastern meadows ; they are 

 readily destroyed by use of bisulphide of carbon. 

 The way to use it is to saturate a rag with a table- 

 spoonful or more, throw it down the burrow as far 

 as you can and immediately stop the hole tight. A 

 sod may be laid over it first, then earth heaped on it. 

 All holes should be treated as they may communicate 

 with each other. 



