FLORIDA STATE HORTICULTURAL SOCIETY 
89 
washed out by the rain down the trunks 
of the trees, where they may become 
lodged in the cracks and crevices of the 
bark and develop mature cankers, even on 
exposed roots. That the disease is car¬ 
ried for great distances on diseased nur¬ 
sery stock, that the spores may become at¬ 
tached to the various forms of animal life, 
insects, birds, dogs, etc., is a demonstrated 
fact. Another danger of carrying infec¬ 
tion is by grove hands and trespassers who 
do not realize the virulence of the canker. 
We have evidence of its being carried by 
wagons, farm tools and automobiles. 
When the spores have once been carried 
to a previously uninfected tree, they may 
develop in any sort of wound or injury in 
the bark, leaves or twigs that is reason¬ 
ably moist and there produce a canker. 
The new growth seems to be especially 
susceptible. No evidence has adduced up 
to the present time to show that a tree 
with reduced vitality is more susceptible 
to infection or that the cankers develop 
more rapidly in such a tree than in a per¬ 
fectly healthy and well nourished tree; 
nor has any evidence yet been adduced to 
show that soil conditions within the pres¬ 
ent range of the disease exert any appre¬ 
ciable effect upon it, beyond the fact that 
plenty of moisaire favors the distribution 
of the spores. 
How long the spores remain alive 
upon the ground under the diseased trees 
is not yet known. It appears safe to state, 
however, that they will remain alive after 
two months, and should they be carried 
up to the new growth produce cankers 
there. We have found in every instance, 
if the ground is not burned over at the 
time that the tree is destroyed, that the 
shoots which grow up from the old stump 
become reinfected. 
With the disease known to be so very 
virulent, it is almost needless to add that 
with the present outlook, citrus groves 
within the diseased area are a poor in¬ 
vestment, and because of this fact there 
is considerable discrimination against set¬ 
ting out citrus. 
After passing through the past year of 
the canker fight, with so very many odds 
against us, knowing, as we do, the deadly 
nature of this disease, it is certainly idle 
to attempt to prophesy what will be the 
future course of the canker, but whatever 
the outcome, we may be sure that the re¬ 
sults of our work in fighting it will in the 
end justify all present efforts. We may 
be sure that this is not the last dev¬ 
astating disease of Florida’s fruits and 
vegetables to appear, and in the future we 
shall need all the knowledge and experi¬ 
ence that has been gained from fighting 
this malady. With the rapid development 
of extensive groves, methods which have 
heretofore been deemed impracticable for 
controlling' citrus diseases will come into 
regular use and the practicable methods 
of the future can only be developed by 
just such scientific research and field work 
as we are now passing through. 
