6 (> 
FLORIDA STATE HORTICULTURAL SOCIETY 
one a gall in the form of a solid ring or 
a broken ring of galls will in all probabil¬ 
ity develop the next season. The dis¬ 
ease frequently extends to the roots. 
The word “extends” is used advisedly, 
for it seems that in nearly all cases the 
trouble originates at or near the crown. 
Beneath the gall the wood in due time 
dies. The tree is weakened and, if not 
broken off by the wind, eventually suc¬ 
cumbs. If the trees become affected 
while young it is quite safe to conclude 
that they will never reach bearing age. 
The disease according to the excellent 
investigations of Tourney, is caused by a 
slime mould, Dendrophagus globosus. 
Tou. It belong to the lowest form of 
plant life, that group over which botan¬ 
ists and zoologists generally disagree, 
each claiming that they belong respect¬ 
ively to the plant and animal kingdom. 
These low organisms are known as myx- 
omycetes. 
The vegetative stage is known as the 
plasmodium. During this stage it con¬ 
sists of free protoplasm capable of am¬ 
oeboid movements. It lives within and 
feeds upon the contents of the cells. 
While it is developing in the tissues of 
the host the cells grow at an exceedingly 
rapid rate, and the gall in consequence 
becomes greatly enlarged. This rapid 
cell multiplication and enlargement in 
the host is caused by the stimulating ef¬ 
fect produced by the dendrophagus and 
the effort on the part of the plant to 
overcome its enemy. The mold passes 
from cell to cell and produces in each 
new cell the same effects as in the one 
from which it has just made its way. 
After a period of growth the plasmo¬ 
dium works to the outside of the gall and 
fruit is produced upon the outer surface. 
The fruiting bodies are almost spherical, 
of a dark orange color, and contain large 
number of spores. These spores, under 
favorable conditions, give rise, once 
more, to the active plasmodium. 
HOW THE DISEASE SPREADS. 
If a few infested trees stand in the 
orchard, it may be carried from tree to 
tree while cultivating. A gall or por¬ 
tion of a gall is broken from a diseased 
tree by the passing cultivator and carried 
on to the next. Perhaps the trunk of 
this may be slightly injured in some way 
and the disease gains an entrance. It 
may possibly in some cases spread from 
contact of affected roots, and we must 
not forget that the spores can be readily 
blown about by the wind. 
It is doubtless true, however, that the 
disease is most generally introduced into 
a grove by planting affected trees or 
trees which have upon them infectious 
material. One gentleman with whom I 
had some conversation regarding this 
disease told me that he purchased from 
a nurseryman a number of peach trees 
and found galls upon some of them. He 
destroyed the affected ones and planted 
the remainder. To-day there is plenty 
of crown gall among his trees. This is, 
I believe, the way in which the disease is 
only too frequently introduced, and an 
infested nursery from which trees are 
sold can be considered nothing less than 
a menace to the peach industry of the 
countrv. 
OTHER TREES AFFECTED. 
The disease affects the plum, prune, 
cherry, apricot, almond, apple, pear, 
raspberry, and probably other trees and 
shrubs. My attention was called to a 
