18 WHITE FLIES INJURIOUS TO CITRUS IN FLORIDA. 
The sooty-mold fungus is a species of the genus Meliola 1 of the 
order Pyrenomycetes. Dr. Webber states that in Florida and Loui- 
siana it is quite generally known as smut or black smut, but as the 
fungus concerned is not a smut fungus these terms are erroneous, 
and their use should be discontinued. When abundant on leaves and 
fruit of citrus, this fungus forms a dark-brown or black membranous 
coating composed of densely interwoven branched mycelial filaments. 
At first this coating covers only limited spots or is not thick enough 
to form a distinct membrane, but later, if the honeydew-secreting 
insects are abundant, the coating becomes thick enough to be entirely 
removed from the leaf and torn like paper. (PI. Ill, figs. 1,2.) 
Frequently the fungus membrane becomes detached at some point 
and is caught by the wind and large fragments torn off. These 
fungus fragments are found scattered about in badly infested groves 
in the fall, being especially noticeable during the winter after a high 
wind or after the trees have been sprayed. 
Dr. Webber recognized several forms of reproductive agents, which 
are easily distributed by various means, but principally by winds. 
The fungus is entirely saprophytic in so far as known, deriving its 
nourishment from the honeydew secreted by certain insects. As such 
honeydew falls mostly on the upper surface of the leaves and on the 
upper half or stem end of the fruit, the sooty mold develops most 
densely in these places, but it is usually present to a greater or less 
extent on the lower surface of the leaves, sometimes developing in 
tufts on drops of honeydew which diseased insects fail to expel in a 
normal manner. Sooty mold also develops on the twigs and in 
some cases on the sides of buildings when heavily infested trees are 
growing near by. 
Seasonal history of sooty mold. — The sooty mold resulting from the 
attacks of the citrus white fly is most abundant late in the season. 
Very little sooty mold develops during the winter months, while the 
films of blackish mycelium gradually become removed from the leaves 
by winds and rains and much is knocked off in picking the fruit, in 
spraying, pruning, fumigating, etc. The thicker the coating of sooty 
mold, the more readily and thoroughly it is removed. By the time 
of the appearance of the new spring growth the greater part of the 
sooty mold on the old leaves has disappeared and from this time to 
the 1st of May there is very little, if any, evidence of a new growth 
of this fungus. Slight blackening of spring growth has been noted 
as far north as Island Grove in Alachua County, Fla., as early as 
May 20, the average number of live larvae and pupae per leaf being 
estimated as about 50, not including old leaves which were practically 
uninfested. By June 20, leaves from Mcintosh, in the same county, 
Generally referred to M. camellia (Catt.) Sacc., but perhaps including more than 
one species 
