38 
FLORIDA STATE HORTICULTURAL SOCIETY. 
found to have received myriads of eggs 
on the lower side of the leaves. 
Mr. Henderson.—I want to touch on 
one point about the white fly. I am not 
properly in the orange belt, but I have 
about one hundred trees. In the fall of 
1904 the white fly appeared on one tree. 
I was told if I would cut all the leaves off 
the one tree I would be free of the white 
fly, which I did. This is good. I had 
them only on the one tree. 
Prof. Rolfs.—In the matter of keeping 
the white fly restricted to the area already 
inhabited. I may cite one instance that 
occurred among a number, in which we 
succeeded in eradicating the fly after it 
had become pretty well established, I am 
referring to the case that happened at 
West Palm Beach. A wealthy gentle¬ 
man who had a fine house at Orlando, 
decided to build a finer one at West Palm 
Beach, and after the house was built he 
carried with him some trees and shrubs. 
After these had been set out, probably 
some six months, it was discovered that 
they were infested with white fly. Per¬ 
mission was obtained to destroy every 
thing to which the white fly had spread, 
all the shrubbery, including citrus planted 
out, were grubbed up and burned, some 
of the stuff such as the stems of banana 
plants that would not burn were thrown 
into the lake. 
Later investigations failed to bring to 
light any white fly, we think therefore, 
that the pest was stopped and eradicated 
at the point of infection. If the infection 
is checked before migration of the white 
fly takes place, I think it entirely possible 
to eradicate it. 
Mr. Cook.—How did you destroy the 
white fly? If he is in the air, is he 
killed, or will he propagate a second 
vear ? 
m/ 
Prof. Rolfs.—The white fly in its com¬ 
plete development goes through the egg 
stage; the larval stage, during the first 
part of which it crawls about and during 
the latter part it remains stationary; the 
pupa stage which to the unaided eye is 
not very different from the larval stage, 
but can be distinguished from it by the 
use of a hand lens; and the last stage or 
adult state. During the last stage is the 
insect able to fly and only during this 
stage does it reproduce itself. 
During the summer season the eggs 
hatch in about three days. The larval 
stage lasts for about twenty five days, the 
third stage or pupa stage lasts for about 
ten days. The adult insect lives only a 
very short time, the females lay about all 
of their eggs during the first twenty four 
hours, the adult flies live only about three 
or four days. The time required for an 
entire generation during the summer 
tim.e, according to Professor Gossard, is 
about forty or fifty days, while during the 
winter portion of the year it may be 
nearly six months. 
Mr. Cook.—Does the white fly only 
live long enough to propagate the first 
time? Does it lay more than one crop 
of eggs? 
Prof. Rolfs.—The white fly appears to 
lay only about twenty five eggs and 
when this hatch is laid off she does not 
appear to lay a second batch. 
Mr. Cook.—I can spray my trees, but 
the white fly commences laying her eggs 
the next night. I have not been able to 
destroy the eggs. 
Prof. Rolfs.—During the summertime 
there is almost a continuous appearance 
of adult flies, there are, however, periods 
during which only few are on the wing, at 
such a time the work of combatting this 
pest can be carried on to best advantage. 
Mr. Cook.—Do I understand that they 
disappear after laying? 
