FLORIDA STATE HORTICULTURAL SOCIETY. 
putting twenty-five gallons of spray On a tree twenty-five feet 
high, I have yet found hundreds of leaves un wet on the under 
surface of the leaves where, in this case, they must be wet if 
the spray is to be effective, as the larva and pupa of the fly 
limit themselves almost exclusively to the under surface. The 
gas treatment, however, overcomes this difficulty, as the gas 
will penetrate to all portions where the air can reach, to every 
leaf under overhanging portions of bark, etc. Itis the nature 
of this method which makes it so effective in a single treat¬ 
ment. 
In fumigation, some care must be exercised, as the potas¬ 
sium cyanide and hydrocyanic cas fumes are poisonous. In 
actual work, however, there is almost no danger if judgment 
is exercised. 0 
Of the various sprays experimented with, kerosene emulsion 
is the one which has been most widely recommended as an 
effective spray for this pest. Our experiments show kerosene 
emuMon to be fairly effective, killing a large number of the 
insects, but that is by no means so effective as the so-called 
rosin washes. The rosin washes are also much cheaper than 
the kerosene emulsion, and are easier prepared if one follows 
the method we now use in its preparation. 
Rosin wash, according to the formula usually given, is pre¬ 
pared by using 70 per cent, caustic soda, and requires several 
hours (from two to three), boiling. This long boiling has 
been a feature against the wash, preventing use. I have found 
that by using the 98 per cent, caustic soda one may shorten 
the time of boiling with apparently as good results. Our form¬ 
ula and method oi preparation is as follows: 
Rosin.20 lbs. 
Caustic, soda, 98 per cent.4f lbs. 
Fisli oil.8 pints, 
Water to ma<e.150 gals. 
Directions for preparing wash—Place rosin, caustic soda 
and fiffi oil in a large kettle and pour over them about fifteen 
gallons of water. Boil this mixture till the rosin is thor¬ 
oughly dissolved. Pour into spray tank and dilute to 150 
gallons (this requires adding about 135 gallons more water). 
Apply on plants in rather a coarse spray. The material after 
boiling may be diluted while warm as well as after it cools, 
but if allowed to cool, a fine precipitate of soap forms, and this 
must be stirred up on diluting it, so as to be thorougly dis¬ 
solved. 
This spray may be preserved in a concentrated form for 
some time before using if desired. 
When the material is removed from the fire after boiling, 
pour in sufficient water to make up for that which has evapo- 
