PLANTS AND ANIMAL PARASITES 



163 



seasons when attacks are expected. The bugs may be 

 kept out of corn fields by plowing a furrow away from 

 the corn, on the side from which the attack is looked for, 

 and strewing stalks of fresh corn in this. As the insects 

 congregate on the corn in the furrow, they should be 

 destroyed with kerosene (294). Persistent and thorough 

 work is essential to success. 



302. The army- worm may often be prevented from 

 migration by plowing a deep furrow, as above directed, 

 and making the side to- 

 ward the endangered crop 

 vertical, with a spade or 

 shovel. The insects will 

 congregate in the furrow, 

 where they may be de- 

 stroyed by dragging a log 



FIG. 68. Sifting-box for applying 

 powders. 



over them. 



303. Grasshoppers and 

 locusts may be destroyed, 

 before they have attained 

 their wings, by drawing 

 over the infested ground a 

 " hopper-doser," which 

 consists of a shallow, 

 sheet-iron pan, with a vertical, cloth-covered back. The 

 pan contains a little kerosene, and the cloth back is 

 kept saturated with the same liquid. The insects jump 

 into the pan or against the cloth back; thus becoming 

 wet with the kerosene they soon perish. Grasshoppers 

 may also be poisoned by distributing bran mixed into a 

 mash with water containing arsenic in solution. Plowing 

 grass land containing the eggs of grasshoppers tends to 

 prevent an attack. 



