FLORIDA STATE HORTICULTURAL SOCIETY. 
83 
resinous looking deposits from the hard¬ 
ening of the gummy exudations. The new 
bark may sometimes heal over; but fre¬ 
quently it dies after a while, and the 
wood usually decays inward, often de¬ 
stroying the tree. 
The cause of the gumming disease is 
not known. The writer is taking up a 
study of this trouble, with the view of 
discovering the cause, if possible, and 
finding a good remedy. Dr. Ernst Bes- 
sey, in his report for 1907, says: “In 
some cases it seems to be due possibly to 
the unfavorable effect of the stock on the 
scion, for it is far more abundant in 
those trees where the scion is larger than 
the stock.” In California a disease called 
“Qummosis,” which causes a gumming 
of citrus trees, has been thought to be 
a physiological trouble. 
Remedy— Gumming has been success¬ 
fully checked in some cases by scraping 
the diseased areas, and painting over the 
wounds with some disinfectant. Carbo- 
lineum, one part to one part of water, 
may be used. Prof. R. E. Smith of the 
California Experiment Station, recom¬ 
mends the following remedy for the 
Gummosis found in that State: Peel off 
the bark without scraping the wood un¬ 
derneath, and cover the wound with a 
kind of grafting wax prepared by melt¬ 
ing four pounds of resin, one pound of 
beeswax and one pound of raw linseed 
oil. This is put on with a brush while 
warm and liquid. 
BLIGHT. 
This is one of the most dreaded, and 
probably most destructive diseases of 
citrus trees in Florida. How many thou¬ 
sands of dollars are annually lost by 
blight, it is difficult to estimate. I11 1895 
Profs. Swingle and Webber estimated the 
loss from this disease at from one hun¬ 
dred to two hundred thousand dollars an¬ 
nually, and it is probably more than that 
now. Blight is one of those diseases that 
is extremely hard to diagnose. Even aft¬ 
er years of experience a grower will tell 
you that he cannot tell at once when a 
tree is struck by blight. It often comes 
on so gradually, without any definitely 
marked symptoms, that one can only be 
sure of a tree having the blight after the 
disease has progressed for some time. 
The disease was first fully described by 
Profs. Swingle and Webber in 1895. It 
usually appears on trees that have pre¬ 
viously seemed healthy and in good bear¬ 
ing condition. It often takes the largest 
and best trees in a grove. The first in¬ 
dication is usually a wilting of the foli¬ 
age, as if the trees were suffering from 
lack of moisture. Most often this occurs 
in early spring, and at first appears most 
pronounced on dry, hot days, but later 
this wilting is seen to persist even through 
the wet or damp weather. The whole 
top may show the disease at once, but 
often a single limb will first show signs 
of wilting. As the disease progresses and 
the rainy season comes on, numerous 
water sprouts are put out from the trunk 
and large limbs. These look healthy at 
first, but finally sicken and die. 
Much technical study and many exper¬ 
iments have been devoted to this disease 
in order to discover the cause and to find 
a remedy. Profs. Swingle and Webber 
did a large amount of work upon it. Their 
work was brought to a sudden end by 
the freezes of 1894-95. Since then, Prof. 
Rolfs, while at the sub-tropical laboratory 
