12 
NATURAL CONTROL OF WHITE FLIES IK FLORIDA. 
Occurring coincidently with one of the most unusual periods of 
drought ever recorded in Florida, the reduction of white flies through- 
out the city limits of Orlando and in the majority of the infested 
citrus 'groves in the vicinity was at first thought to be due to the 
weather conditions. An analysis of the available data concerning the 
weather conditions in different locations where the white flies have 
become successfully established indicates that with little doubt this 
idea was erroneous. 
Fungous parasites were thought by some to have been responsible 
for the situation here considered. While such a conclusion might 
have been drawn in 1906 from observations in a few selected groves, 
the white-fly conditions in 1907 in these same groves offered positive 
proof that the fungous parasites exerted an insignificant, if appreciable, 
influence toward the general reduction in the numbers of white flies. 
The brown fungus appeared to be effective in one small grove of about 
100 trees located near the center of the city of Orlando. Aside from 
this, no instance of effectiveness of fungous parasites in the locality 
referred to was known to the senior author, who is responsible for the 
observations. A comparison of the conditions during 1906 and 1907 
in representative groves and in yards in and near Orlando will show 
the status of fungous parasites with relation to the situation. (See 
Table I.) 
Table I. — White-fly conditions in and near Orlando, Fla., during 1906 and 1907. 
Grove 
Varieties. 
White flies, 1906. 
Parasitic fungi, 1906. 
Foliage. 
No. 
1906. 
1907. 
1 
2 
Mostly grapefruit; a 
few oranges and 
tangerines. 
Grapefruit, oranges, 
and tangerines. 
Mostly oranges; a 
few grapefruit and 
tangerines. 
Oranges entirely 
Oranges entirely 
Oranges, grapefruit, 
and tangerines. 
Both A. citri and A. 
nubifera in about 
equal numbers. 
do 
Traces of yellow; no 
red. The former 
abundant on a few 
trees. 
Yellow and red con- 
sidered t o g e t her 
more abundant 
than elsewhere in 
locality. 
Red very abundant 
in one section. 
Traces of brown. 
Slightly black- 
ened. 
Varying from 
slightly to 
moderately 
blackened. 
In general 
very black. 
Slightly black- 
ened. 
Blackened 
G ener ally 
blackened. 
Clean. 
About same 
3 
4 
Mostly A. citri; a 
few A. nubifera. 
All A. citri, so far as 
observed. 
Mostly A. citri; very 
few A. nubifera. 
do 
as in 1906. 
Clean. 
5 
6 
Absent, so far as ob- 
served. 
Red abundant in cer- 
tain places, traces 
in other places, and 
absent in others. 
Traces of brown. 
Clean. 
Clean. 
Grove No. 1 is that belonging to Capt. J. S. Jouett and is located 
near the north end of Orange Avenue in Orlando. 
Grove No. 2 is that of Mr. C. B. Thornton and is located near 
Orange Avenue, a few hundred yards southeast of grove No. 1. 
The condition in this grove (No. 2) is especially significant, since, 
notwithstanding the comparative abundance of the parasitic fungi 
