FLORIDA STATE HORTICULTURAL SOCIETY. 
65 
fumigators weigh the potassium cyan¬ 
ide and measure the acid, arranging 
the dosage for each tree in the racks 
of the tray, the cyanide in the upper 
rack directly above the pitcher of acid 
for any given tree. One man usually 
measures the acid and generates the 
gas and is known as the “generator/^ 
From two to three men look after the 
changing of the tents and are known as 
^^tent pullers.” Another man known 
as the *^tent kicker” follows the tent 
pullers and pulls or kicks in the tent 
at the bottom and also raises the edge 
of the tent while the generator passes 
in with the can of potassium cyanide, 
pitcher of acid and the generating jar 
containing the required amount of wa¬ 
ter. The jar is placed near the base of 
the tree and the acid poured in follow¬ 
ed by the cyanide, after which the gen¬ 
erator passes out quickly and the edge 
of the tent is dropped into position. 
The commissary is usually located 
where it will be most conveniently sit¬ 
uated for the entire night’s work. Af¬ 
ter shifting the tents and generating 
the gas, all hands return to the com¬ 
missary and the materials weighed up 
for the next change of tents. This 
procedure is varied somewhat accord¬ 
ing to the number of tents operated 
and the individual practices of the fum¬ 
igators. 
POISONOUS NATURE OF THE GAS. 
The necessity of observing simple 
precautions in fumigating with hydro¬ 
cyanic acid gas is so well known that, 
although this is one of the most dan¬ 
gerous poisons, there is no record of 
a fatal accident resulting from its use 
as an inseoticide. After removing the 
tent the contents of the jar should be 
emptied between the rows of trees and 
covered with earth. When emptied close 
to the trees the roots are likely to be in¬ 
jured, especially when the soil is very 
porous. Great care should be taken to 
avoid pulling the tents over any of this 
material even after it is supposed to be 
carefully buried. 
EXPENSE OF FUMIGATION. 
Wherever the surrounding condi¬ 
tions are such that a grove would re¬ 
ceive full benefit from the almost com¬ 
plete extermination of the insects, the 
cost of fumigation would ordinarily be 
about the same as three sprayings, but 
its efficiency in checking the white fly 
would be equal to at least six sprayings 
at the rate of three per year. At the 
outside, the cost, making ample allow¬ 
ance for wear and tear of tents, should 
not exceed that of four sprayings. 
Even on this basis, the cost of fumi¬ 
gation in a period of two years would 
not exceed two thirds the cost of the 
best of spraying while the results ob¬ 
tained would be far more satisfactory 
and uniform. These estimates are 
based on the cost of fumigation with 
untreated canvas. With canvas made 
approximately gas tight, the cost 
would doubtless be reduced fully lone- 
third. 
Fumigating tents are expensive as a 
first outlay; those large enough to 
cover a thirty foot tree costing about 
$90.00 and to cover a fifteen foot 
tree, about $20.00. It is not advisable 
as a rule for an orange grower to in¬ 
vest several hundred dollars in fum¬ 
igating tents for his exclusive use, al¬ 
though many with extensive groves 
would doubtless prefer to do this. In 
some citrus fruit growing countries 
where fumigation is practiced against 
scale insects, several growers form a 
5 
