50 
Colorado Experiment Station 
20. Sulphur 
Flowers of sulphur has been found to be very destructive to the 
mites and red spider. It can be dusted on the plants in the dry form 
or may be mixed with water, one pound to three gallons, and used 
as a spray. First stir the flowers of sulphur into a small quantity 
of soapy water and then dilute to the desired proportion. 
The mixture must be stirred vigorously, as the sulphur settles very 
quickly. 
21. Hot Water 
Hot water may be employed to kill insects and eggs upon dor¬ 
mant nursery stock. Temperatures from 135 to 145 degrees for 
10 seconds are usually harmless to dormant plants, and will kill all aphis 
eggs. 
In some tests made at the college, those trees submerged for 10 
seconds in water of 145 degrees were slightly injured, but 5 seconds 
in this temperature killed plant lice eggs, and showed no injury to 
the stock. One hundred thirty degrees was not very effective on 
some eggs treated. Probably the safest and most effective tempera¬ 
ture is 135 to 140 degrees, with 10 seconds submergence. 
SUBSTANCES THAT KILL BY BEING INHALED 
22. Carbon Bisulphide 
This is a colorless liquid with a very disagreeable odor. It is very 
volatile and the fumes are poisonous to both plant and animal life. 
Its chief use as an insecticide is against household and granary pests, 
borers and under-ground insects. For household and granary pests, 
use one pint to each 1000 cubic feet of space or for each 100 bushels 
of grain. Place in shallow vessels so it will evaporate quickly. Keep 
building closed for 24 to 36 hours. 
For borers, by means of an oil can, squirt a few drops of carbon 
bisulphide into openings made by the borer, then plug with mud. Ants 
can be destroyed by punching a hole or two in their nests and pour¬ 
ing in one or two ounces of the liquid, after which the hole should 
be closed, and a wet blanket thrown over the hill. It is sometimes 
used against the woolly aphis on apple roots by making several 
holes 6 to 12 inches deep and about a yard apart about the tree and 
pouring i or 2 ounces of the liquid into each hole. Close the holes 
immediately. 
Caution: Keep all fire away while using this material, as the 
gas is very explosive when mixed with air. 
23. Hydrocyanic Acid Gas 
This is the standard fumigant for most horticultural purposes, 
and is often used to destroy insects in dwellings and mills. Many 
states require all nursery stock sold within the state, to be fumigated 
with this gas. 
