FLORIDA STATE HORTICULTURAL SOCIETY. 
95 
of the jars known as “residue” on the 
roots of the trees after fumigating. 
Of course, this should not be charged 
to the fumigation of the trees any 
more than we would charge against 
the cost of spraying the injury that 
would result from emptying against 
the base of a tree a half barrel of spray 
mixture left over at the end of the 
day. Such carelessness must, however, 
be guarded against. 
Mr.-What is the cost of fumiga¬ 
tion ? 
Dr. Morrill—The cost of fumigation 
for the average size tree, is about 50 
cents. For large trees, the cost may 
go up to $1.00, or more. But, as I 
have said, it is better and cheaper to 
fumigate than to spray, and spraying 
will cost more in one year than a sin¬ 
gle fumigation that will last two years 
or more. The eggs of the insect will 
probably hatch out by the middle of 
December, and the best time for fumi¬ 
gating, I would say, would be from 
the first of January to the time of the 
appearance of new spring growth of 
the citrus trees in February. 
In connection with the scale insects 
question, I would say that in one case 
where we have made pretty careful 
observation, we have been unable to 
find a single live pupae or red scale 
in any of the trees in a fifty-acre grove, 
though in previous years they had 
caused much trouble and caused injury 
to the extent of several hundred dol¬ 
lars per year. 
Mr.-In your cost of fumigating, 
do you include labor, etc. ? 
Dr. Morrill—We include every¬ 
thing; the work, material, and the 
wear and tear on the tent as well. 
Mr.-It seems to me the tents 
should be mildew proof. 
Dr. Morrill—That should be done if 
it can be done without increasing the 
weight too greatly. However, I know 
one preparation that will do it. 
Mr.-Did you ever use sugar of 
lead and alum? 
Dr. Morrill—That is what I speak 
of. 
Mr.-How much would it add to 
the weight of the tent? 
Dr. Morrill—It would not add ap¬ 
preciably to the weight. 
Dr. Inman—What is the size of the 
tents you use? 
Dr. Morrill—The largest tents are 
about eighty feet in diameter, and 
octagonal in shape. These are large 
enough for seedling trees thirty-three 
or thirty-four feet in extreme height. 
Budded trees twelve feet high require 
tents about thirty-five feet in diameter. 
Mr. Mote—After you have thor¬ 
oughly and carefully fumigated a 
grove that is badly infected with 
white flies, do you consider that you 
have done away with the white flies 
for two seasons? 
_ 1 
Dr. Morrill—From our observation 
of the groves we have fumigated, we 
believe it will take at least two years 
before the fly will increase to the point 
of smutting the leaves or fruit. By 
fumigating it thoroughly every other 
year, I think you can keep your fruit 
entirely free from smut, unless sur¬ 
rounding conditions are unfavorable. 
I refer to neighboring groves where 
no attempt is made to control the fly. 
Mr.-Does it kill the rust mite? 
Dr. Morrill—It kills the adult, but 
not the eggs. 
