60 NATURAL CONTROL OF WHITE FLIES IN FLORIDA. 
spores and mycelia. The best general infection by brown fungus 
which has come under the observation of the authors was one 
secured in a grove 1 of Mr. W. C. Temple at Winter Park, by Mr. 
Frank Sterling of Deland. The ordinary method of spraying spores 
was used. The spraying was done between October 2 and 16, 1908. 
Doubtless there was more or less secondary spreading in the fall, but 
there was no appreciable spread in 1909 before April 23, when the 
records were made. At that time brown fungus was found to be 
present on 7 per cent of the leaves, averaging 23 pustules per infected 
leaf or 16 pustules for the entire lot of 100 leaves examined. 
As regards the extent of infection attainable by methods herein 
discussed, the authors consider the results far from satisfactory. The 
dipping of white-fly infested branches in water mixtures of spores of 
Aschersonia and ground-up leaves infected by brown fungus would 
appear to represent a maximum of favorable influences so far as prac- 
ticable methods of introduction or spread are concerned, and the fail- 
ure to secure more than a slight infection, comparatively speaking 
under any conditions indicates the relative insignificance of human 
efforts as compared with natural methods of spread. 
PRACTICABILITY OF INCREASING THE EFFICACY OF FUNGOUS PARASITES. 
The efficacy of the fungous parasites may be said to be increased, in 
a broad sense, whenever they are introduced or even spread naturally 
into white-fly-infested citrus groves in which they previously did not 
exist. The subject to be considered here, however, relates to the ordi- 
nary meaning of the expression " increasing the efficacy" after the 
initial introduction has already been accomplished. Apparently there 
are only two opportunities for effort in tins direction. The first con- 
sists in producing conditions more favorable for the development of 
the fungous parasites and the second consists in artificially spreading 
the infection. 
IMPROVEMENT OP CONDITIONS FAVORING THE DEVELOPMENT OP FUNGOUS PARASITES. 
A line of work which naturally suggests itself in connection with an 
investigation of this kind is the improvement of conditions favoring 
the development of fungous parasites. Preliminary work in spraying 
trees with clear water in the absence of regular rainfall gave no 
promise of benefit. Common observations made in hammock groves 
in Lee and Manatee counties are sufficient to prove the futility of 
i No examination of this grove was made prior to Deo. 8. 1908, but since no brown fungus was found in 
several surrounding groves, since none was known to occur nearer than 5 miles, and since no previous 
attempt had been made to introduce it, it was presumed that this fungus was introduced by Mr. Sterling. 
On the other hand, yellow and red fungi sprayed at the same time were presumed not to have been suc- 
cessfully introduced or spread by this application, since on the opposite side of the road a grove in which 
no artificial introduction had been made was found to have an average of twice as many red-fungus pus- 
tules and six times as many yellow-fungus pustules per leaf. 
