FLORIDA STATE HORTICULTURAL SOCIETY. 
57 
An examination of the table shows 
that with the single exception of kero¬ 
sene emulsion, all the insecticides as 
used gave satisfactory results. The low 
mortality obtained by the petroleum 
fuel oil was due, I think to the imper¬ 
fect spraying. I had two inexperienced 
men and we started our work with that 
insecticide. It may be that since they 
were new at the work they did not do 
it so effectively as later when the other 
materials • were applied. The results 
with commercial lime sulphur are grat¬ 
ifying. The two brands were of the 
same specific gravity. It would appear 
that this efficient insecticide for San 
Jose Scale can be recommended for 
spraying when the fly is in the young 
stages. In our other experiments on 
the pupae we have not been able to get 
satisfactory results. 
It is very interesting to me to find 
that kerosene emulsion, made after the 
Hubbard formulae and used at 1-30 or 
2 per cent, of oil, killed only 71 per 
cent, of the insects. It had been my 
idea that since 4 to 5 per cent, had been 
found by Mr. Hubbard to kill the pur¬ 
ple scale, that 2 per cent, would surely 
be strong enough to kill the young 
stages of the whitefly. I believe that 
the temperature at the time the mate¬ 
rial is applied to the tree is important 
when kerosene emulsion is used. I 
have examined Mr. Hubbard’s records 
and find that all his results were ob¬ 
tained in winter, when the temperature 
was perhaps not sufficiently great to 
cause the kerosene to evaporate before 
the insects were killed, while the above 
experiments were carried on in March, 
when it was quite warm. Of course, if 
it had been used twice as strong, better 
results would have been obtained, but 
it seems to me 2 per cent, should have 
produced a greater killing than was 
obtained. 
It will be noticed that Formula IV 
used at 1-100, or one-half of 1 per cent, 
of oil, killed 84 per cent. This was 
used as a check on the same strength 
to which nicotine sulphate at the rate 
of 1-320 was added. The material 
when the nicotine was added killed 97 
per cent. The nicotine was very vola¬ 
tile and applied at some inconvenience. 
It caused us to cough and was so 
strong that it affected our eyes. Ap¬ 
parently this is a promising field for 
future work. As yet I have never ex¬ 
perimented with the new tobacco pro¬ 
duct, “black leaf 40.” I understand it 
is many times stronger or concentrated 
than the nicotine sulphate, and is non¬ 
volatile, which perhaps would not only 
eliminate the inconvenience of apply¬ 
ing it, but which would make it remain 
longer on the tree than the nicotine 
sulphate. 
The petroleum fuel oil and the dis¬ 
tillate oil emulsions do not seem to 
have any immediate effect upon the 
loosening of the sooty mold. The par¬ 
affine oil emulsions loosened the sooty 
mold perfectly. 
In order to determine if any injury 
followed the application of any of these 
insecticides, I watched the grove care¬ 
fully for some days. I decided that no 
apparent injury had been done even to 
