Plants as Affected by Animal Parasites. 171 



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 toward the endangered crop verti- 

 cal, with a spade or shovel. The insects will congregate 

 in the furrow where they may be destroyed by drag- 

 ging a log 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-cov- 

 ered 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, 

 and soon perish. Grasshoppers may 

 also be poisoned by dis- 

 tributing bran mixed into 

 ! B a mash with water con- 

 taining arsenic in solu- 

 tion. Plowing grass land 

 I containing the eggs of 

 grasshoppers tends to 

 A prevent an attack. 



304. Apparatus for 

 Applying Insecticides. 



BIO. 68. sifting box for apppiy- Po ^ers are readily ap- 

 ing powders. plied to low-growing 

 plants, as the potato, cabbage, etc., by means of a sift- 

 ing box consisting of a pail with a perforated bottom, 



