10 Farmers’ Bulletin 1261. 
sooty-mold fungus develops, giving the foliage and fruit a black- 
ened appearance (figs. 6 and 7). It attacks both the West In- 
dian and Guatemalan races of avocados. This species is very 
sensitive to varying changes of temperature and prefers and de- 
velops more abundantly in protected places. It is very abundant 
on trees on the Florida Keys and on islands along the southern 
coasts of Florida. The direct injury is caused by the white fly in 
the larval stages extracting the plant juices from the foliage. The 
indirect injury is caused by the resultant sooty mold on the foliage 
and fruit. Where this sooty 
mold is abundant considerable 
extra labor is required during 
packing to clean the fruit. 
SEASONAL HISTORY OF THE 
WHITE FLY. 
During the dormant season 
of the avocado— December, 
January, and February—this 
species is inactive, remaining 
over on the foliage in the pupa 
stage (fig. 5). With the be- 
ginning of new growth in the 
spring, its activities commence 
and the adult is then to be 
found in great numbers on the 
: pies oan new growth, depositing eggs 
Fic. 5.—The avocado white fly: Pupe on (fig. 4). During the first part 
lower surface of avocado leaf. of March the adults usually 
are present and mate, and the females deposit their eggs on the 
lower surface of the young foliage. The eggs are very small objects, 
pearly white in color, and are usually placed in circles. During the 
spring and summer from 8 to 10 days are required for the egg to 
hatch. About 100 eggs are laid during the little over a week of its 
existence. 
The young when hatched from the eggs are very small, oval in 
shape, of a yellowish color, and semitransparent, with two orange- 
colored areas showing in the body region. They soon settle down on 
some portion of the lower surface of the leaf and commence to extract 
the plant juices by means of their hairlike mouth parts. The young 
larve molt in about an average of 5 days. As they grow the body 
becomes more circular in outline, and during the process of growth 
quantities of honeydew collect on the tops of the individuals. Often 
these drops of honeydew become many times the size of the insect. 
The honeydew drops from the body of the larva on to the upper 
