The Pensacola journal. (Pensacola, Fla.) 1898-1985, 1910-10-05

THE AGRICULTURAL EXPERIMENT
STATION ISSUES BULLETIN ON
BEST MEANS OF DESTROYING
BY e. w. Berder.

While the best time for introducing
the fungus parasites of the whitef1y Is
during the period of summer rains
one of the best times to spray with
contact insecticides is during the fall
Spraying with contact insecticides can
be employed with advantage during
October or November. Do not begin
to spray until ten days or two weeks
after the whitefly has quit, or nearly
quit, flying. BY that time the eggs de,
posted by that brood will have hatch
ed. 1t is the young larvae that are
most easily killed. By mid-winter
these larvae will have developed to
the fourth or older stages, and are
not then SO easily destroyed. In add1-
ton to the larvae being larger and
stronger in winter, the spray employ
ed may be less effective, because OF
the cooler weather. The advantages
of spraying for the whitefly early in
the fall are:
1. The larvae are young and easily
killed.
g. There are few rains to interfere
with spraying.
3. The larvae are killed before
they wax fat on the trees. and so do
not drain the trees SO long as when
they are not sprayed until winter.
If there is not sufficient whitef1y
present in the fall to produce visible
sooting of the trees. spraying may be
postponed until winter; when, OF
course, a stronger insecticide must be
used.
Having sprayed thoroughly at the
time above noted, it will not be neces-
sary to spray again before spring.
Ten days or two weeks after the
spring brood Of whiteflies have quit
swarming (tLat is, by the time the
eggs have ha .ched) the spray may be
applied effectively.
Spraying Solutions.
Our experiments show that 80 to 95
the thickened condition of the fourth
STACEY have been readily killed by l
pound Of whale Oil soap to 6 gallons
Of water. Solutions as dilute as l
pound to gallons of water have
given good results. Failures to get
good results in fall may have been
due to cooler weather at the time of
application, since most liquids are less
penetrating and less active chemical
ly at lower temperatures. 1t, there
lOE0, appears ucSil dDlc " use WudlS-
Oil soap stronger in fall than / to G.
say ! pound to 4 gallons of water-ex-
cept when the temperature approx
mates that of summer. Other spray
ing solutions, such as miscible oils
and proprietary brands. may be en-
pIoyed at the strengths recommend
ed by the manufacturers.
Fungi.
AS general rule, it Is not best to
attempt to introduce and spread fun
gus after the summer rains have ceas-
ed. After this time the fungi spread
but i.,tle and are of but little value in
checking the brood of larvae then on
the leaves. Sometimes, however, fun
gus may be introduced in the fall in
order to give it an early STRAIT next
spring, should favorable conditions
arise at that time. The writer has,
as late as October, successfully intro
duced fungus which resulted in an eff
fective growth by the middle OF the
next summer.
Groves Treated With Fungus.
Those who have been depending up
on fungus to check the whitef1y, and
have allowed a cover-crop of some
kind to grow tall and rank in order to
help fungus growth during the period
of rains, should cut this down and
use it as mulch, or plow II under as