28 NATURAL CONTROL OF WHITE PLIES IN ELOEIDA. 
Orlando have demonstrated, however, that ordinarily the overrun- 
ning of from 20 to 90 per cent of the pustules does not prevent the 
fungus from spreading rapidly when the weather conditions are 
favorable. The Cladosporium spreads most rapidly during dry 
weather and upon leaves bearing many pustules of the Aschersonia. 
The yellow Aschersonia pustules in all ages and conditions are 
subject to the attack of the Cladosporium. (See PL VI.) The former 
is frequently so closely followed by the latter that even when spread- 
ing rapidly practically all of the Aschersonia pustules show the 
beginning of the hyperparasitic attack before they reach more than 
one-fourth of their normal size. 
During 1907 and 1908 the Cladosporium was especially active in 
August and October. In 1907 its spread was unusually rapid 
between October 17 and 31, during very dry weather, and by Novem- 
ber 15 of the same year had so overgrown the yellow fungus in one 
nursery at Orlando that 92.6 per cent of the pustules were affected. 
This estimate is based on the examination of 50 leaves upon which 
there were 3,110 pustules of the yellow Aschersonia. Again, between 
August 6 and 13, 1908, when no rain had fallen since July 28, it 
spread with such rapidity as to render useless numerous experiments 
started in July at Drennen. During the summer of 1909, when the 
rain was more abundant than during 1907 or 1908, the Cladosporium 
did not spread with such rapidity in any of the groves at Orlando. 
THE BROWN FUNGUS. 
(JEgerita zcebberi Fawcett.) 
Dr. H. J. Webber, then of tl^United States Department of Agri- 
culture, first discovered the brown fungus, parasitic upon the immature 
stage of the citrus white fly, in March, 1896, in the grove of J. H. 
Yiser, Manatee, Fla. Dr. Webber states that while the spread of the 
fungus was phenomenal from March to December of that year and 
killed so many larvae and pupae that the fruit was clean, he was 
unable to discover it in any of the surrounding groves heavily infested 
with the fly. Although a thorough study of the fungus was made by 
its discoverer at several seasons of the year, no trace of fructification 
was found; hence it was impossible to determine its relationship. 
The fungus was, therefore, popularly named the brown mealywing 
fungus, or, as it is now more commonly called, the brown fungus. 
During the past three years the authors have noted the frequency 
of the occurrence of patches of minute brownish spores on leaves 
infected with this fungus, arising apparently from its ground mycelium 
As these spore patches occurred only upon leaves infested with the 
fungus and upon no other leaves no matter how heavily coated with 
sooty mold, it was concluded that they must be the fruiting bodies of 
the fungus. A specimen leaf was sent to Mrs. Patterson, the mycolo- 
