NATURAL CONTROL OF WHITE FLIES IN FLORIDA. 
INTRODUCTION. 
The control of the citrus white fly {Aleyrodes citri R. & H.) by 
means of the natural enemies already established in Florida has 
long been a subject concerning winch there have been many diverse 
opinions and insufficiently supported conclusions, but very little defi- 
nite knowledge. Opportunities for extended investigations of the 
subject were first offered in 1906 when the work was taken up inde- 
pendently by the Bureau of Entomology — as one phase of the white- 
fly investigations begun in July of that year — and by the Florida 
Agricultural Experiment Station. While the field work conducted 
in the two investigations has been largely along somewhat parallel 
lines, the duplication of work in the case of such a difficult and impor- 
tant problem is of great advantage in advancing our knowledge upon 
which final conclusions must be based. 
It is not feasible to present in this publication more than a small 
selection from the large amount of data which have been secured in 
connection with the investigations of natural control, but it has been 
the purpose here to present such data as are necessary properly to 
support important conclusions. The nature of the more important 
conclusions is such as to render unnecessary complete discussions of 
minor topics, which would be necessary under other circumstances. 
The investigations of the parasitic fungi were conducted by the 
senior author during the season of 1906; by the senior author, by 
Mr. E. L. Worsham, now State entomologist of Georgia, and by the 
junior author during the season of 1907; by the junior author during 
1908, and by the senior and junior authors jointly during 1909. 
Mr. W. W. Yothers has aided at various times in connection with 
field work and has furnished certain data, as hereinafter specifically 
credited, in connection with the " white-fringe fungus." Mr. Wor- 
sham has been specifically credited where his results have been util- 
ized. Practically all of the experimental results included herein are 
based on the work of the seasons of 1908 and 1909. 
Thanks are extended to Prof. P. H. Rolfs, Dr. E. W. Berger, and 
Prof. H. S. Fawcett, of the Florida Agricultural Experimental Sta- 
tion, for the many courtesies extended during these investigations. 
Acknowledgment is also made of assistance rendered by Mrs. Flora 
W. Patterson, mycologist of the Bureau of Plant Industry, to whom 
many specimens of fungi have been submitted for examination and 
for information. The colored plate is the work of Mr. J. F. Strauss, 
of the Bureau of Entomology. 
