Plants as Affected by Animal Parasites. 157 
in a vessel containing water at 120° F. This treatment 
must be used with caution. 
300. Insect Attacks Sometimes Become Formid= 
able from the vast number of the individuals. The chinch- 
bug,* the army-worm 7 and various species of locusts or 
grass-hoppers sometimes devastate large tracts of country. 
For the destruction of these insects, special means must be 
employed. 
301. The Chinch-Bug may be, in a measure, controlled 
by burning over all grass land in early spring, in 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 probable, 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 toward the endangered crop vertical, with 
a spade or shovel. The insects will congregate in the fur- 
row where they may be destroyed by dragging a log over 
them. 
304. 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, and soon perish. Grasshoppers may also be 
* Blissus leucopterus. + Leucania unipuncta. 
