46 
FLORIDA STATE HORTICULTURAL SOCIETY. 
flow of gum from breaks in the bark on 
the trunk or large limbs some distance 
from the ground, and in the later stages 
hy a shagginess of the bark. Only recent¬ 
ly has it been known that there was any 
fungus in connection with this trouble 
.and it has been attributed to various caus¬ 
es, such as cold, the wrong kind of fertil¬ 
izers, borers and the like. And while one 
or more of these factors may weaken or 
injure the tree so that the fungus may 
more easily enter, it now seems probable 
that this organism is one of the agents 
in causing one form of disease known as 
gummosis. 
DESCRIPTION. 
The disease first makes itself apparent 
on citrus trees by the oozing out of a thm 
watery gum, which sometimes runs down 
the bark in lines, forming what is known 
as “tears.” Later the gum thickens and 
collects in large quantities at the cracked 
places in the bark. As the disease pro¬ 
gresses, the bark cracks still more and 
assumes a shaggy ulcerated appearance 
over patches three inches to a foot or 
more in length. The diseased patches 
may extend entirely around the limb or 
may be confined to one side of the branch. 
The gum seems to exude most during the 
growing period in the spring and sum¬ 
mer, and sometimes entirely ceases in the 
fall and winter. In cases where the gum¬ 
mosis is not too severe, new bark is 
formed under the old and the surface 
becomes marked by ridges, warts and res¬ 
inous-looking deposits and at the edge of 
the diseased area are large bits of bark 
which have been pushed up and are hang¬ 
ing by one edge. When the disease is of 
some age, it may easily be mistaken for 
the true scaly bark. 
A species of fungus belonging to the 
genus Diplodia '(Diplodia natolensis ) has 
been found under the bark of diseased 
patches on citrus trees and the same fun¬ 
gus has been found in connection with 
diseased limbs on gumming peach trees. 
It was first obtained from the interior 
of gumming peach branches by E. W. 
Berger of the experiment station in 
July of last year and was afterwards 
isolated by him from gumming peach 
branches from five different coun¬ 
ties in the state. The two most 
widely separated localities were West 
Tampa and Pensacola. 
In September of the same year, what 
appeared to be the same fungus was ob¬ 
tained from the gumming orange limbs 
and afterwards obtained from six differ¬ 
ent counties of the state. Both peach and 
orange trees in the greenhouse were in¬ 
oculated by taking bits of this fungus 
which had been grown in the laboratory 
and inserting it under the bark. In each 
case, the bark of healthy trees was cut in 
exactly the same way. These peach and 
orange trees in which the fungus had 
been inserted under the bark gummed 
copiously, very much in the same manner 
as they do when infected in the orchard; 
while those which had been cut in the 
same way but no fungus inserted, healed 
up without gumming in any case. This 
seems to show that this particular fungus 
may be one of the agents at least in in¬ 
ducing the gum and it is probable that in 
many cases some slight injury allows the 
fungus to get in. This is not thought to 
be true in all cases, as the following will 
indicate: 
Some inoculations were made by plac¬ 
ing the fungus on the surface of the bark 
