30 
FIELD EXPERIiMENTS FOR THE PROTECTION OF CORN 
AGAINST CHINCH-BUG INJURY. 
Barrier Experiments. 
Experiment of i8gj. — In my ninth entomological report, pub- 
lished in 1898, I gave an account, in an article on "Midsummer 
Measures against the Chinch-bug,"* of a field experiment made in 
♦Twentieth Rep. State Eiit. 111., pp. 37-44. 
1895 ^^^ the destruction of that insect as it passes in June and early 
July from small grain to corn. The measures used in this experi- 
ment were a combination program of a dusty furrow for the ar- 
rest and destruction of chinch-bugs in dry weather, a coal-tar line 
with post-hole traps for use when the ground is too wet to pulverize, 
and kerosene emulsion for the destruction of the insect on the corn 
itself. 
This operation, carried on in Effingham county from June 5 to 
15 by one of my assistants, was highly successful in the protection 
of corn growing adjacent to a heavily infested 20-acre field of 
wheat, approximately twelve bushels of chinch-bugs being destroyed 
in the process at a cost of less than five dollars for the materials used. 
Extreme conditions prevailed at the time of this experiment. 
Injury by chinch-bugs to grass, small grains, and corn had contin- 
ued in this locality for some years with increasing intensity, and 
these insects had become so numerous in the wheat that they had 
already destroyed the crop and virtually all other grass-like vegeta- 
tion in the field referred to, by the 5th of June. Compelled to leave 
the wheat to avoid starvation, they moved out of it rapidly, wholly 
deserting it within a very few days. The corn adjacent was thus 
exposed to immediate and complete destruction by the invading 
horde, and would inevitably have been soon destroyed if active 
measures had not been taken to protect it, a fact made perfectly ap- 
parent by the fate of other similarly situated fields in the neigh- 
borhood. 
The weather of the season had been very dry, and it was in- 
tensely hot, conditions which, although unfavorable to the infested 
crops, were unusually favorable to the easy success of measures for 
the destruction of the chinch-bugs. A dusty furrow, readily made 
and maintained between the \yheat and the corn, trapped the in- 
sects in myriads as they attempted to pass from one field to the 
other, and the heat of the dry dust in the bottom of the furrow, 
