4 Farmers’ Bulletin 1261. 
INJURIOUS INSECTS OF THE AVOCADO IN FLORIDA. 
THE DICTYOSPERMUM SCALE." 
The avocado, as is the case with deciduous fruits and citrus fruits, 
has its destructive scale enemies, the most important of which, in 
Florida, is the dictyospermum scale. The adult scales (fig. 1, a) 
are circular, or slightly elongated, closely resembling other scales 
of a similar nature. They vary in color from a light yellow to a 
reddish brown. 
CHARACTER OF INJURY. 
The dictyospermum scale is a pest in the avocado nursery as well 
as in the bearing grove and has been found to infest both the West 
Indian and Guatemalan races of avocados. In the nursery it finds 
special protection where the trees are crowded together in blocks. 
In the grove it attacks the twigs and branches and, where numerous, 
the foliage. The branches so attacked (fig. 1, 6) are gradually 
weakened and ultimately become of little use to the tree. The 
branches at the base of the tree are generally attacked more severely, 
being more protected from the elements than those toward the top 
(fig. 3). Where trees have been seriously attacked they in time 
assume a nude appearance, due to the destruction of the foliage-bear- 
ing twigs and branches. Branches and twigs severely infested soon 
become roughened and crack considerably, affording entrance places 
for various destructive fungi (fig. 2). 
LIFE HISTORY AND DEVELOPMENT OF THE SCALE. 
The young of the dictyospermum scale insect are hatched beneath 
the scale which covers the adult female. They are broadly oval in 
outline and yellow in color. They are much flattened creatures, 
provided with six legs, a pair of antenne, and an apparatus for 
sucking the juices from the tree. They are exceedingly small, ap- 
pearing as mere yellow particles. They remain beneath the scale 
covering a short time and after emerging crawl over the branches 
and twigs and soon settle down and begin their growth, living at 
the sole expense of the tree. 
Several days after settling the young scale assumes a circular 
shape and begins to exude a mass of fine white cottony threads 
which finally cover the entire insect. About four days after birth 
the scale covering commences to change again, and the cottony- 
appearing substance is cast away for a more compact scale or nipple- 
like covering, the center of which is whitish with a grayish tinge, 
with white outer edges. Underneath this scale covering the insect 
grows and goes through the process of molting several times. With 
the first molt the legs and antenne are shed with the skin. The young 
1Chrysomphalus dictyospermi Morgan, 
