52 THE SUGAR-BEET WIEEWOEM. 
EXPERIMENTS WITH DETERRENTS AGAINST THE WIRE WORMS. 
A fairly exhaustive series of experiments was carried on, using 
repellent substances against the larvae. While some of these experi- 
ments are a repetition of the work done by Comstock and Slinger- 
land, the greater number are rather an addition to their work. From 
the start tliis work promised little, but was undertaken because, if 
successful, it would afford a remedy which would give immediate 
results, and this is most important with this insect. | 
A system was adopted regarding both the nature of the expeii- J 
ments and the times of application. Three tests were given each 
experiment in the spring, when the larvae were most active, and a 4 
test was given in the fall just before their hibernation period. The 
last one was on a small scale and was carried on merely for the sake 
of added evidence. 
Flowerpots were the cages used in the spring experiments. It 
was found that if the hole in the bottom was stoppered with cork, 
none would escape in the time of the experiment. It was also 
noted that where about half an inch of dry soil was placed on top 
of the damp soil of the cages the wireworms would never come 
entirel}^ to the surface. This treatment, then, allowed the flower- 
pots to be buried to the surface of the soil out of doors, and with the 
exception that the larvae were a little crowded it gave outdoor 
conditions. 
In the first test of each experiment 50 larvae were used and the 
test covered 20 days. In the two remaining tests in the spring 25 i 
larvae were used each time and the experiment was allowed to run 
for 30 days. In the experiments with deterrents the following sub- 
stances were tested: 
(1) Carbolic acid. 
(2) Carbolic emulsion. 
(3) Turpentine. 
(4) Kerosene. 
(5) Kerosene emulsion. 
(6) Whale-oil soap. 
(7) Potassium cyanic! solution. 
(8) Potassium cyanid solid. 
(9) Copperas solution. 
(10) Copper sulphate. 
These deterrents were used on beet and lima-bean seeds, both of 
which are attacked by this species. It was hoped that in these ex- 
periments a deterrent could be discovered for protecting the tender 
roots until the plant had secured a fair start. If this could be ac- 
complished the injury due to wireworms would be materially lessened. 
(11) Potassium sulphid solution. 
(12) Tar water. 
(13) Ash water. 
(14) Nicotine sulphate. 
(15) Free nicotine solution. 
(16) Cresol (so-called coal-tar creosote). 
(17) Salt solution. 
(18) Lead chromate. 
(19) Dry sulphur. 
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