NATURAL EFFICACY OF FUNGOUS PARASITES. 45 
When the data in Table IX are examined with due consideration 
of circumstances known to the authors, it appears that the fungous 
diseases in the eight groves were ineffective in 1908, but produced a 
condition in that year resulting in satisfactory freedom from the 
insects and blackening of the foliage in one grove in 1909 and with 
prospects for such a condition in at least one grove in 1910. As the 
investigation of fungous diseases was discontinued in 1909, there are 
no records as to the condition of the groves the following season. 
Since the actual cause of the temporary freedom from injurious 
attack is often obscure, as the foregoing records show, it is evident 
that less detailed observations, such as have formed the basis of the 
estimates of the authors of previous publications (including the 
senior author of the present publication), have favored the fungi 
rather than otherwise in crediting them with complete efficacy to 
the extent of one year in three. 
During 1906, 1907, 1908, and 1909 a large number of records were 
accumulated in regard to the efficacy of fungous diseases during those 
years in about 25 citrus groves located in different sections of Florida, 
mostly in Lee, Manatee, Hillsboro, and Orange counties. In several 
instances authentic information has also been secured in regard to 
the efficacy of the fungi in previous years, as shown by the necessity 
for washing the fruit to remove sooty mold. 
More than one-half of the total number of records are concerning 
hammock groves and the list includes the majority of groves in 
Florida where the fungous diseases have been exceptionally effective 
during the period under observation. In two instances groves have 
been noted or authentically reported as free from blackening for two 
successive years after being well freed from the insects by fungous 
diseases. These are offset, however, by several instances of groves 
showing no benefit whatever for three or more years after the fungous 
diseases have become well established. In the case of one grove in 
Manatee County, unfavorably located with respect to a general 
nursery with citrus, China trees, privets, and other food plants, it 
had been necessary for the owner to wash the fruit every year for a 
period of more than 10 years, except for less than one-half of one 
crop. Although the red and the brown fungi were always found 
present in abundance at each of the several examinations made by 
the authors, the trees were always found to be more or less blackened 
and in one instance noted as being as thoroughly blackened as any 
grove seen in Florida. 
The hammock groves of Manatee and Lee counties have offered 
the best opportunities for observations of the fungous diseases under 
the most favorable conditions. During 1906 and 1909 the majority 
of the Manatee hammock groves were practicaUy free from blackening 
by sooty mold, but the crop of 1907 in these same groves was as 
