FLORIDA STATE HORTICULTURAL SOCIETY. 
77 
that the nature of these low fungi was 
known. Much advance has been made 
in their study and in finding means of 
controlling them, but there is yet much 
that is not understood. The advance in 
this line is slow, because of the extreme 
smallness of many of these minute forms, 
and the difficulty of keeping track of any 
one individual in its infection of a tree. 
When a new disease occurs, one may pos¬ 
sibly find a dozen different microscopic 
fungi growing upon or into a 
diseased area. It is necessary 
to isolate these fungi in the 
laboratory, and then to prove by inocula¬ 
tion experiments which kind, if any, is 
the cause of the disease, or whether the 
fungi are simply present as the result of 
an injury from some other source. The 
primary cause of a disease once being 
known, it is a simpler problem to discover 
a means of prevention or cure for it. 
One discovery of this kind may prove of 
vast value to a whole country, yet it can 
never be known beforehand how much 
time it will require to make the discovery. 
SCALY BARK. 
A disease that is confined almost en¬ 
tirely to one section of the State and has 
attracted considerable attention there, is 
that known as Scaly Bark. It is sometimes 
called by the growers “11180 or “nail- 
head rust.” This disease should arouse in¬ 
terest, not only in the section in which it 
is prevalent, but in other sections as well, 
because of the danger of its being intro¬ 
duced into new regions. The advantage to 
the grower of being able to recognize at 
a glance a new disease at its earliest start 
is great. For there are times when by the 
destruction of a single tree in the corner 
of a grove, or of one tree near a house or 
barn, into which a disease has been car¬ 
ried, an entire grove might easily be saved 
from being diseased. From, our study of 
this disease there is every reason to be¬ 
lieve that Scaly Bark is infectious, and 
that it may spread easily from tree to tree 
or from one grove to another. A history 
and description of this disease were given 
by the writer in the Proceedings of this 
Society for 1908, page 101. It has also 
been more recently described, with its 
remedies, in Bulletin 98 of the Florida 
Experiment Station. It has been estimated 
that the yearly loss of fruit from this dis¬ 
ease in one citrus-growing section of the 
State is near 20,000 to 30,000 boxes of 
oranges, and this is in addition to the con¬ 
stant weakening of the trees. The loss of 
crop in this region is anywhere from noth¬ 
ing up to 25 per cent, in good years, and 
in unfavorable years it may be as high as 
75 per cent, in badly diseased groves. 
Description— Scalv bark is primarily 
a bark and {rind disease of the sweet 
orange. The wood is only affected sec¬ 
ondarily, by poisoning due to the wither- 
tip fungus. The bark of the trunk and of 
branches of all sizes may be affected; but 
the greatest injury is done to the younger 
branches and twigs up to> about one-half 
inch in diameter, and to the fruit. 
On the branches and twigs there de¬ 
velop more or less circular or oval spots 
one-sixth to one inch across, rusty in col¬ 
or, and with well-defined margins. The 
bark becomes brittle, begins to crack, and 
forms small flakes or scales. These spots 
are at first scattered but may increase in 
number to such an extent as to became 
joined together. The branch is Tardy 
killed in the first year. During the second 
