150 INJURIOUS INSECTS OF I909 AND IQIO. 
Hyprocyanic Actp Gas: ‘This gas is made by dropping po- 
tassium cyanide into sulfuric acid and water. The fumes are 
deadly to all kinds of animal life, and the gas is used only in special 
cases. As this gas is fatal to human life as well as to insect life, 
it should be used only by an expert. 
TRON SuLFIDE MixtTuRE: This is a comparatively new, but, 
according to Circular No. 58 of the Bureau of Plant Industry, U. 
S. Department of Agriculture, very promising fungicide. It was 
tried in particular on apples, and gave splendid results, both in pre- 
venting fungous diseases and in non-injurious effects on the fruit. 
In preparing this fungicide, it is recommended that a self-boiled, 
lime-sulfur mixture be prepared as previously described except that 
10 pounds of lime and 10 pounds of sulfur are used. The mixture 
is diluted to 40 gallons and then 3 pounds of iron sulfate, (cop- 
peras) dissolved in about 8 gallons of water, is added. 
KEROSENE: This is an excellent contact insecticide, the merest 
particle of it coming in contact with any part of the anatomy of an 
insect is fatal. Pure kerosene, however, will burn the leaves of 
plants, consequently it is only recommended to be used in the pure 
form when trees are dormant, or against insects off of plants, for 
instance, the killing of grasshoppers by hopperdozers, or household 
insects, etc. 
KEROSENE Emutsion: This is probably the best form into 
which kerosene can be put for spraying growing plants. A stock 
emulsion is made as follows: 
Hard laundry soap, shaved fine, % pound. 
Water, 1 gallon. 
Kerosene, 2 gallons. 
Dissolve the soap in boiling water, remove from the stove and 
immediately add the kerosene; churn with a bucket pump until a 
soft, butter-like, clabbered mass is obtained. One part of this stock 
solution is added to ten or twelve of water for spraying. If the 
stock solution is properly made this can be used on tender foliage 
of plants for such insects as plant lice, etc. 
Lime SuLFur: Within the last few years this wash has be- 
come very prominent. It is one of the best scale insecticides yet 
discovered, and will kill the eggs of plant lice. As an insecticide 
it has an accumulative action, being more active a few weeks after 
spraying than at the start. Since coming into prominence as a 
