42 
mixture being used. A part of the corn was now about two and a 
half feet high, and the chinch-bugs were mainly behind the leaf- 
sheaths or within the conical cavity at the tip of the plant. The 
kerosene mixture was applied in part by hand as before, and in part 
by pouring from a common sprinkling can, but the former method 
was found the more rapid and also the more economical of material. 
As shown by examination the following day, not a plant was in- 
jured by this treatment, and only a few bugs were left alive, mainly 
on plants with leaves so rolled and curled as to protect the bugs 
within them. A careful count was made of all the bugs, living and 
dead, found upon ten average hills, including those on the ground 
about the bases of the plants, with the result that eighty-eight per 
cent, of all found were dead. An additional treatment was given to 
the corn still infested, and July 24 the owner of the field, after a 
careful examination, found an average of twenty to twenty-five liv- 
ing bugs per hill. The corn was at this time beginning to tassel. The 
same treatment, would, of course, have destroyed any number of 
chinch-bugs with which the corn might have been infested. As the 
three quarters of an acre invaded by the bugs was part of a forty- 
acre field much of which would have been infested and injured if 
this section had not been promptly dealt with, the result of the 
treatment was much greater than the protection of the corn actually 
covered by it. At the rate at which this treatment was applied it 
would take two hours to treat an acre, or an average of five acres 
per day. 
At Odin, experiments were made July 6 with solutions and mix- 
tures of various strengths to test the effect upon both insects and 
corn. The plants were young — only about six inches high — and 
the liquid was thrown upon them by hand, care usually being taken, 
however, to avoid filling the cavity at the tip of the plant. The 
emulsions were made by beating, as before, the kerosene being 
heated before adding it to the soap solution. 
Kerosene emulsion was applied in dilutions varying from four 
to ten per cent, of kerosene, and whale-oil soap was used in solutions 
varying from an eighth of a pound to two pounds to the gallon of 
water. With a four per cent, kerosene emulsion applied in a way 
to drench the entire plant and fill the cavity within the terminal 
tuft of leaves, no injury whatever was done to the corn, and the 
chinch-bugs were nearly all killed. A similar treatment with a five 
per cent, emulsion, however, was injurious to the plants. Some 
leaves were wilted at the base the following day, and seventeen 
out of the thirty plants treated were finally killed. Still more serious 
injury of course followed the use of the stronger mixtures. 
