35 
(2) Distribution. —This disease was found'at only one point in Lake 
County. Dr. Martin found it in 1886 at Green Cove Spring. It does 
not seem to be widespread nor at present of much importance, but is 
recorded here that attention may be called to it, so that its nature may 
be known and its progress watched. 
(3) Causes. —The cause of this disease is a parasitic fungus ( Colletotri - 
chum adustum , Ellis)* which draws the nourishment from the leaf it 
inhabits. It belongs to a group of fungi that are known to be imper¬ 
fect forms, audare supposed to be a phase of growth in the life history 
of some mature form of fungus. The particular form of which this 
species is a phase of growth is not known nor even suspected. Its 
connections are to be looked for among some of the many species of 
• * 
ascomycetous fungi which inhabit decaying vegetable matter, and for 
this reason are supposed by the uninformed to be of no economic iuterest. 
VI.—SOOTY MOLD. 
(1) Nature of the Disease .—The leaves of certain trees badly affected 
with some kind of scale insects become covered with a sooty layer, 
which is of a dark drab or dirt color early in its growth and finally 
becomes sooty black. The layer thus formed is only loosely attached 
to the smooth surface of the orange leaf aud frequently comes off in 
patches. 
(2) Distribution. —This disease does not appear to be very widespread 
on the orange trees in Florida! and the material collected was young 
and immature. We found it, however, more abundant on Magnolia 
fcetida , JSmilax sp., and other shrubs which were abundantly affected 
with scale insects. 
* (3) Causes. —In 1876 Dr. W. G. Farlow published an elaborate paperf 
giving a full account of this disease as affecting the orange and olive 
trees of California, and referring it to a fungus ( Capnodium citri , Berk. 
& Desm.) which feeds on the honey dew produced by the bark lice. 
While the fungus draws no nourishment from the orange leaves them¬ 
selves it must, if abundant, seriously interfere with the process of assimi¬ 
lation and therefore be regarded as injurious. v 
(4) Remedies. —In the paper above mentioned, spraying with a strong 
solution of alkali soap is recommended. The disease has not yet made 
sufficient progress in Florida to demand much treatment, aud with the 
natural enemies of the scale iusect to check their development is not 
likely to prove a serious difficulty. 
* Described as Phyllosticta adusta , E. & M., but Mr. Ellis (In litt 16 May, 1891) refers 
it to Colletotriclium. 
t At Los Angeles, California, in 1886, we saw this disease in great quantity, entirely 
covering the leaves in some of the orange groves. With the disappearance of the 
scale insect the disease will disappear likewise, 
t Bull. Bussey Inst, i, 404-414,1876. 
