84 
FLORIDA STATE HORTICULTURAL SOCIETY. 
be treated in winter in order to give them a 
better chance to set fruit in spring. If co-opera¬ 
tion can be effected it is possible to do the work 
so thoroughly that no further treatment will be 
necessary before next fall or winter. If co-op¬ 
eration for an entire locality is impracticable it 
may be possible to effect co-operation on the 
part of the owners of the localized groups of 
groves. Where no co-operation whatever is pos¬ 
sible each grower should treat his own trees. In 
this instance spraying should be the method of 
winter treatment. It would be inadvisable to go 
to the expense of fumigation where the grove is 
not isolated and reinfestation certain, but spray¬ 
ing should be done. Later in April or May, when 
the grove has become re-infested from the 
groves of indifferent neighbors it should be 
sprayed again. There is a time in April or 
May when the whitefly larvae are young and ea¬ 
sily destroyed by whale oil soap (i pound to 6-9 
gallons of water) or by any other good insecti¬ 
cide sufficiently diluted so as not to injure the 
leaves or young fruit. This period comes about 
two weeks after the spring brood of adults has 
disappeared from the wing. After that, during 
the period of summer rains, if conditions are at 
all favorable for fungus growth (plenty moist¬ 
ure, and good condition of trees) the fungus dis¬ 
eases of the whitefly should be introduced. Fin¬ 
ally, if necessary, the trees should be sprayed 
again in October or November; in which case 
treatment during next winter will probably 
not be necessary. (See also under Spring, 
Summer,'* and Fall Spraying.) 
SPRING, SUMMER AND FALL SPRAYING. 
Spring Treatment .—'Spring treatment should 
begin about two weeks after the winged white- 
flies have ceased swarming and have disappeared. 
There are then only young larvae beneath the 
leaves. This period comes in April or May, and 
earlier, depending upon the season and the lo¬ 
cality. In localities where the spring rains are 
abundant and the general moisture conditions 
throughout the season generally suitable, the fun¬ 
gi, preferably the red Aschersonia, may be in¬ 
troduced as previously directed. • Where the con¬ 
ditions for the fungi are not suitable, or where 
it is desired to depend altogether upon spraying, 
the spring period indicated is a most suitable one 
in which to spray. The advantages of spraying 
at this time may be summed up as follows: (1) 
The whiteflies are in the young larval stages 
and are easily killed; (2) they are mainly on 
new growth and more easily sprayed: ( 3 ) the 
larvae are destroyed before sapping the strength 
of the new growth, and before much sooty mold 
has developed: (4) there are but few rains to 
interfere with the spraying. 
Summer Treatment .—Spraying may also be 
carried on in summer during the latter part of 
June or July after the second brood of adult 
whiteflies has passed its period of greatest num¬ 
bers for 10 days or two weeks. There being all 
stages present in considerable numbers at all 
times, and since rains are generally abundant, 
spraying at this time is not advised, except where 
the trees are suffering greatly. The fungi can 
generally be introduced to good advantage at 
this time and they should be spread freely when¬ 
ever the whitefly is present in sufficient numbers. 
Fall Treatment .—Fall is a very important time 
to spray for the whitefly and treatment may be¬ 
gin in October or November, or soon after the 
adult whiteflies of the late summer brood have 
wholly or nearly disappeared, and after the last 
layings of eggs have hatched. Groves sprayed 
in the early part of November with a spraying 
mixture whose principal ingredient was whale 
oil soap (about 1 pound to 10 gallons of water), 
showed that about 90 per cent, of the larvae 
had been killed. For the early fall spraying, 
whale-oil soap should not be used less than 1 
pound to 6 gallons of water and may be used 
stronger. The advantages of fall spraying may 
be summed up as follows: (1) The young lar¬ 
vae are abundant and easily killed; (2) (they 
are killed before 'they wax fat on the trees; 
(3) the (trees remain clean for nearly five 
months; (4) there are few rains to interfere 
with spraying. 
SPRAYING SOLUTIONS. 
Since spraying for the young whitefly larvae 
must be done in spring, summer, or fall, when 
either tender leaves or fruit are on the trees, it 
is evident that a spraying solution must be em¬ 
ployed which will not injure the foliage or the 
fruit. Almost any good contact insecticide can 
be employed, provided it is sufficiently diluted. 
It has been found that soap solutions of 1 
pound of soap to 6 gallons of water, destroyed 
all the larvae in the first three stages, and most 
of those in the fourth apd pupal stages. Thorough 
spraying resulted in destroying between 90 and 
96 per cent, of all the larvae on the leaves. Soap 
solutions of 1 pound of soap to 9 gallons of wa¬ 
ter destroyed about 90 per cent. Good’s potash 
whale oil soap No. 3 was used, and also Octagon 
soap. It is probable that any kind of soap will 
be effective against these young larvae. In win¬ 
ter the soap solution should be used stronger, 
about 1 pound to 4 gallons pf water; but a weak 
solution used in spring, summer, or fall, when 
the whitefly larvae are in the younger stages 
and the weather very warm, will give as good 
results as the stronger solution in winter. 
“Golddust” was also used on young larvae at 
the rate of 1 pound to 4 gallons of water, and 
