The Florida agriculturist., 1907-08-28
The White Fly-It's Food Plants.

Ihe White Ely-ltS FOOu fAdnIS'
Editor Florida Agriculturist:-
In an editorial in the issue OF the
Agriculturist, dated August l6, l note
the statement expressing the common
belief to the effect that the citrus white
fly breeds upon Water Oaks. This state
ment is technically true, according to
an entomologist who has made an ex-
tensive collection of the insects of the
genus Aleyrodes, to which the white t1y
in question belongs, but for all practical
purposes, however, it is safe to d1sre-
gard oaks as food plants. Even though
the adults may occasionally deposit eggs
upon oak leaves when these trees are
growing near to infested orange groves,
it is doubtful if the insects ever reach
maturity in such cases.
The subject Of the food plants OF the
citrus white fly is an important one,
for the success of remedial measures
of all kinds is largely dependent upon
the list of food plants being naturally
very much restricted DR.. E. w. Berger
has published the complete list of food
plants, so far known to entomologists,
in Bulletin 88 of the Florida Experiment
Station. These plants are as follows: {:
Citrus (all varieties), Cape Jessamine,
Chinaberry and Umbrella trees, Privets,
Persimmons, Mock Orange, Prickly Ash,
Viburnum, Ficus, Water Oak and Scrub
Palmetto. There is no positive record
of the citrus white fly reaching matur-
ity on Water Oaks or Scrub Palmettos.
The other known food plants, besides
the citrus trees, can readily be elimi-
mated in practically all cases at the
pleasure of the orange growers, or at
least when public opinion has decided
that orange growing in any particular
district is of more Importance to the
community than the trees and shrubs
fly breeds. Bay trees and gall berry
bushes are commonly believed to be
food plants of the citrus white fly, but
so far all the evidence have seen points
to the extreme improbability of this
species of white fly ever breeding upon
them. Bay trees (infested with two
other species of white fies) have been
carefully examined along the margins
of a thickly infested orange grove, in
some cases the branches of the Bays
actually touching those of the oranges,
but in no case was a citrus white fly
egg, larva or pupa, found on the leaves
of the Bay trees. The presence of a
few specimens of adult citrus white flies
under the circumstances would not have
been regarded as of any special signifi-
canoe, but only single adult was found.
In the case of the Gall berry bushes,
the sooty mold is commonly observed
thereon, but so far as observed is due
usually to the Florida wax scale (Cer-
coplastes floridensis) and never to the
citrus white fly. The presence of sooty
mold upon various plants is far from
being an indication of infestation by
the citrus white fly, for there are over
70 other species of white flies known
to occur in the United States, and, in
addition, many thousands of insects less
closely related to the citrus pest in
question, all of which produce the honey
dew upon which the sooty mold thrives.
The list of food plants given above
is no doubt incomplete, but it is proba-
BILE that only very few mature plants,
and these of little consequence, will need
to be added. Entomologists can recog-
nize additions to this list only upon
a careful examination of specimens of
the insects to determine whether it is
the citrus white fly or some other species
which is concerned.
Yours truly,
A. w. Morrill,.
Orlando, Fla, August II, 1907.
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