FLORIDA STATE HORTICULTURAL SOCIETY. 
77 
BY SPRAYING ON SPORES OF THE FUNGUS. 
If it is decided to^ introduce the fungus 
by means of spraying on spores, care 
should be taken to spray against the under 
surface of the leaves. Future experiments 
may show that this precaution is not nec¬ 
essary but we are not likely to go very 
far astray by adopting it for the present. 
Forty well developed pustules having the 
bright red spots upon them are sufficient 
for a pint of water. Two well infected 
leaves may be taken as representing the 
forty pustules but one leaf will frequently 
have the required number and often more. 
A pint of the solution, I believe, should be 
sufficient for a tree of ordinary size where 
a very fine spray is used. From this it 
will be seen that spraying is the most eco¬ 
nomical in so (far as infecting material 
required is concerned. Three thousand 
leaves will about fill a bushel measure. 
Two leaves per tree to make the spray, 
gives us fifteen hundred trees that can he 
treated with this number of leaves. Where 
an abundance of leaves are available the 
spraying solution may be made stronger; 
it cannot be made toO' strong. After hav¬ 
ing poured the water over the leaves and 
stirred the same about for a few minutes, 
fifteen to thirty minutes should be allowed 
for the spores to become dissolved out of 
the red spots on the pustules of the fun- 
• gus. Then the mass should be stirred 
again, thoroughly, in order to wash out 
all the spores possible. Do not permit the 
solution to settle but strain the liquid at 
onee through a piece of cheesecloth or 
fine wire sieve. An atomizer spray is to 
be preferred because it does not require so 
much liquid to spray the tree. At all 
events, a nozzle that produces a very fine 
spray should be used. The above esti¬ 
mate of one pint of liquid per tree was 
based upon an atomizer spray. If on the 
other hand, no atomizer is available, a 
spraying machine may be employed. The 
spraying solution should under no condi¬ 
tions be permitted to stand in a copper or 
brass tank, for the amount of copper that 
would go into the solution might be fatal 
to the spores, as these are very sensitive to 
copper. If a spraying machine made 
wholly or in part of copper or brass, must 
be used, the same should be thoroughly 
cleaned before using, and then the work 
should be done as expeditiously as pos¬ 
sible. If it is necessary to use the copper 
or brass reservoir connected with the 
spray pump or spraying machine this 
should be partially filled with the solution, 
enough only being put in, to spray three 
or four trees. Spray the solution on the 
under surface of all the infested leaves 
giving special attention to the heavily in¬ 
fested new growth. If it happens that only 
a limited amount of the spraying solu¬ 
tion is available it may be diluted with 
water. Thoroughly spraying all the trees 
with a weaker solution is considered pre¬ 
ferable to spraying half the trees, or only 
part of each tree, with a stronger solution. 
It goes without saying, that it would be 
futile to introduce fungus into a tree not 
infested with whitefly. The fungi in ques¬ 
tion, so far as known, can thrive only 
upon the whitefly, so that there would be 
nothing for them to live upon in a non- 
infcsted tree. It will also be well to wait 
before introducing fungus into a tree until 
the whitefly larvae can be abundantly 
found under a considerable number of 
leaves. To spray every tree in a grove re¬ 
gardless of the individual requirements 
of each tree would frequently lead to 
waste of material and labor. The writer’s 
plan of campaign would be as follows: 
Start the fungus in all the trees in which 
