FLORIDA STATE HORTICULTURAL SOCIETY 
67 
This white fly is usually more abundant 
in groves situated on the keys and 
stretches of land between the ocean and 
bay inlets along the lower east coast of 
Florida. This probably is due to the fact 
that the temperature registers more even¬ 
ly in these localities. It is found, how¬ 
ever, in varying numbers on the mainland 
and especially in nurseries on young trees 
in lath houses, where its activities are 
more or less protected and not greatly in¬ 
terrupted by the weather conditions. 
The adults which appear in the spring 
of year emerge from the over wintering 
pupal stage clustered in great numbers on 
the lower surface of the older foliage. 
The adults deposit their eggs in great 
numbers on the new growth, the larvae 
which hatch from the eggs pass their ex¬ 
istence on the lower surface of the leaves. 
This species also produces an abun¬ 
dance of honey dew which accumulates 
upon the upper surface of the foliage and 
fruit. The common sooty mold fungus 
later develops in this honey dew deposit 
eventually giving the Avocado foliage 
and fruit a decided blackened appearance. 
Control. 
Where this pest is present in a bearing 
grove it may be controlled by spraying 
with the regular oil emulsion spray. Two 
sprayings will generally control the white 
fly, one during the spring after the fruit 
has set and the first general flush of new 
growth is sufficiently hardened, using a 
strength of one gallon to eighty of wa¬ 
ter. Another application should be made 
in the fall when the adult flies are for 
the most part off the wing and the foliage 
is turning dormant using a strength of 
one gallon to seventy of water. 
THE DICTYOSPERMUM SCALE. 
At times various scale insects give the 
Avocado grower considerable trouble. 
One in particular is the Dictyospermum 
Scale, Chrysomphalns dictyospermi Mor¬ 
gan. In appearance it does not differ ma¬ 
terially from a great many scales and re¬ 
sembles quite closely our common Florida 
red scale in shape and is a light amber in 
color. 
Where this scale is present in a grove 
or nursery it attacks the twigs and branch¬ 
es, and where very numerous may often 
be found on the foliage. The branches 
attacked are gradually weakened and ul¬ 
timately become of little use to the tree. 
The twigs and branches soon become 
roughened and crack considerably, there¬ 
by affording entrance places for various 
injurious plant diseases. As time goes 
on an infested tree shows a decided lack 
of lateral twigs and branches resulting in 
a badly formed tree. 
Control. 
The best time to control this pest on 
the Avocado is when the trees are dor¬ 
mant, usually from the middle of Decem¬ 
ber until the first of February. The 
scale is readily killed by using an oil 
emulsion spray at a strength of one gallon 
to seventy gallons of water. Two appli¬ 
cations of an oil emulsion spray at a 
three or four-week interval will control 
this pest. 
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