62 
FLORIDA STATE HORTICULTURAL SOCIETY. 
re-infestation of the grove in question 
from the fly left alive after the fumiga¬ 
tion. My figures will show that the 
grove would not have been black if 
flies from the neighboring grove had 
not entered, but the figures do show 
that all the trees which bordered your 
other grove became heavily infested 
with the first brood. In fact, they were 
more heavily infested with the last 
brood than the other trees. I can prove 
that a great many flies came from your 
other grove. 
I would like to bring out again the 
fact of the great difficulty in finding an 
oil or spray which would have perma¬ 
nent qualities and yet not injure the 
trees, and I think we have solved that 
in this paraffine oil emulsion. I feel 
confident now, if they are used in the 
proper way; that is, not twice or three 
times as strong as they are recom¬ 
mended, but erring, if anything, on 
the weaker side, that you people will 
not have any trouble. This grove 
which was sprayed last January, where 
these Nos. Ill and IV were used, show 
evidences yet of the oil, and apparently 
has not suffered any damage. 
Mr. Thompson: The reason I 
brought up the question as regards the 
fumigation, is because it has been 
stated down our way that the influence 
of the fumigation would remain with 
us for two years and the trees would 
not be infested. I could not believe it. 
Mr. Yothers: The only data I have 
to substantiate this is the grove I men¬ 
tioned as being completely isolated. 
Mr.-: It seems to me a fumi¬ 
gation every third winter will keep a 
grove in very good shape. 
Mr. Yothers: If the fly is very 
scarce, it does much more good to 
fumigate or spray than it does where 
the fly is abundant, because, some way 
or other, I cannot explain why, fumiga¬ 
tion kills only about 99 per cent. 
Doubtless there is some reason which 
we are unable to explain. It does not 
make any difference whether there are 
600 insects on a leaf, or only two or 
three, there always seems to be some 
escape. I remember in one instance I 
counted 600 insects which had been 
killed on one leaf, and right in the cen¬ 
ter of the leaf was one live fly. I can¬ 
not explain why that insect was not 
killed. 
Dr. Berger: I wish to make a few more 
remarks on the whitefly. The gentleman 
is still with us and, of course, is a very 
live subject, as some of you are experi¬ 
encing. I have done a little figuring, and 
shall also make a few remarks about the 
treatment of the mites. 
The whitefly, without any treatment, 
would probably cut the orange crop in 
half, or nearly so. We will assume for 
the sake of calculation that it does cut it 
in half. Suppose we assume the basis of 
our crop to be six million boxes per year. 
If the whitefly cuts this in half, we will 
have a crop of three million boxes. 
We find that the fungus diseases in¬ 
crease the crop one million boxes per year, 
which, at a dollar a box, is $1,000,000 
saved. The fungi probably save us a mil¬ 
lion dollars per year. This leaves two 
million boxes a year to work for by 
