FLORIDA STATE HORTICULTURAL SOCIETY. 
85 
several small twigs (with leaves) of the 
Cape jasmine before referred to, and well 
infested with 'whitefly. A portion of 
this material was placed in a small cloth 
sack and slightly buried at the foot of 
a large magnolia tree near the Univer¬ 
sity. The magnolia was chosen because 
no citrus or jasmine was near at hand. 
On March 22 live adults were emerging 
and some of the leaves were still green. 
Another portion of this material was 
placed under a bell jar (with open top 
and covered with cheese-cloth) on sand 
in the greenhouse. Live adults were ob¬ 
tained as before at the end of two months 
and a few of the leaves were still green. 
In both experiments, however, the lar¬ 
vae on the leaves which had turned dark 
or dried, soon died. 
These observations leave no doubt in 
my mind that some whitefly can be car¬ 
ried through the winter on dead, partly 
dried and browned leaves, scattered un¬ 
der trees, especially when so placed that 
they do not dry sufficiently to crumble, 
although some of the leaves examined 
were quite dry. It was not possible to 
know how long these leaves had been in 
the condition in which we found them, 
and whether the larvae there could have 
matured; for when leaves are allowed to 
dry in the laboratory all larvae have been 
observed to die. In regard to the pupae 
there can be no doubt about their matur¬ 
ing, as one adult at least was caught in 
the act of emerging from its case while 
others developed into adults when taken 
to the laboratory, as previously stated. 
It is estimated that the leaves in question 
had fallen from the trees two weeks to 
two months previously, but they may 
have been older. The experiments with 
the fresh green jasmine leaves indicate 
furthermore, that it is possible for such 
leaves to become buried in the sand or 
otherwise protected, so that they remain 
green for at least two months, allowing 
whitefly larvae to mature upon them 
in time to infest the early new growth 
of the trees. 
Extermination by Defoliation .—The 
previous observations and experiments 
indicate pretty clearly why the attempts 
at exterminating the white fly at DeLand 
in February, 1907, by defoliating the 
trees have failed, notwithstanding that 
precautions were taken to burn all the 
leaves. Some of the trees had been 
banked with earth, and as the “fly’ 1 ap¬ 
peared in greatest abundance in these 
trees after the defoliation, this again in¬ 
dicates the possible source of the re-in¬ 
festation, since these banks of earth about 
the stems of the trees would be ideal 
places for preserving leaves, as the pre¬ 
viously stated experiments show. That 
the defoliation of all the trees at De- 
Land at the time referred to was never¬ 
theless useful can hardly be doubted, 
since it must have been at least equiva¬ 
lent to a season’s spraying or fumiga¬ 
tion in keeping the “fly” in check. The de¬ 
foliation was completed after the partial 
defoliation by the December freeze of 
1906, so that the burden of it was much 
less. I believe that defoliating whitefly- 
infested trees after a partial defoliation 
by a freeze may frequently be advisable, 
but doubt if the wholesale butchery of 
the trees at Marysville, California, of 
last year was advisable, and doubt, fur¬ 
thermore, if they will be successful in 
exterminating the white fly there unless 
they keep up the extreme vigilance now 
exercised for at least five or six years. 
No doubt the growers at Marysville, Cal¬ 
ifornia, would have done better to have 
checked the “fly” as best they could dur- 
