Insects of Shade Trees and Their Control. = We 
mixture first and then dilute it as needed. This stock mixture may 
be made up in quantities, and if properly prepared it should keep 
for some time. 
Kerosene-emulsion stock is most conveniently prepared as follows: 
ISCrOSCNES eee eee eee Ss EES er era§! Le to IS gallons__ 2 
Fish oil or laundry soap (or soft soap, 1 quart.) _______ pound__ #4 
SOV 2 fleet meat ine Beeemaneree SA tO eee oe Ss gallon... 1 
Put the water and soap into a wash boiler or similar vessel and 
heat until the water boils and the soap is dissolved; remove from the 
fire, add the kerosene, and stir vigorously for about five minutes 
until the mixture is creamlike in consistency. A convenient way to 
make the mixture thorough is to pour the soap solution and kerosene 
into the tank of the spray pump and, through the nozzle, to pump 
the mixture back into the tank for several minutes. 
For spraying, this stock mixture is diluted with water, which is 
best done at the time and in quantities needed. For summer spraying, 
on trees in foliage, add 5% gallons of water to each gallon of the stock 
preparation. For winter use, on dormant trees, 13 to 24 gallons of 
water are added to each gallon of the stock. For smaller quantities 
see Table I, p. 30. 
POISONED CONTACT SPRAY. 
In this preparation the contact solution is used as a conveyer of 
the poison in situations where the ordinary water solution of the 
poison could not penetrate. It was specially devised to reach and 
kill borers while they are still feeding in the bark, and is prepared 
as follows: 
In each gallon of water used for diluting the contact preparation, 
be it kerosene emulsion or water-soluble oil, dissolve 1 ounce of sodium 
arsenite, before making the mixture. Sodium arsenite is readily 
soluble in water and is procurable in drug stores. The crude or 
commercial product, which is cheaper, will answer the purpose. This 
preparation is injurious to foliage, which should be borne in mind 
when applications are made with it. 
NICOTINE SULPHATE. 
Nicotine sulphate is a specific remedy for aphids or plant-lice, but 
other soft-bodied insects can also be killed with it. It isa liquid extract 
of tobacco procurable in a variety of stores under a variety of trade 
names and varying in strength. The preparation is merely diluted 
with water before use, and the proportions are usually given on con- 
tainers. The 40 per cent nicotine sulphate is the most commonly 
available; although when properly diluted, any strength of the stock 
preparation will answer. It is necessary to add 1 ounce of soap to 
each gallon of the spray to insure its spread and adhesion. 
