6o 
FLORIDA STATE HORTICULTURAL SOCIETY. 
give a formula so that the government 
will have something to recommend, the 
composition of which might be made 
public. I do not say that good results 
cannot be had with proprietary insecti¬ 
cides; some of our best results have 
been obtained with these proprietary 
articles. Heretofore these proprietary 
insecticides have been recommended to 
be used at too great a strength. I cer¬ 
tainly would not apply them in the 
summer time any stronger than i per 
cent., the same as I have these formu¬ 
lae mentioned—one per cent, of their 
oil contents. In the winter time I 
■would apply them about the same as 
I have these formulae—about i 1-4 or 
1 1-2 per cent. 
Mr. Thompson: It has been stated 
that after a grove has been fumigated 
that it will be free from fly for possibly 
two years, although there may be 
groves around it infected. Is that true? 
Mr. Yothers: Experiments show 
that unless a grove is almost com¬ 
pletely isolated, it does not remain free 
from fly very long. I do not think a 
statement like that can be substan¬ 
tiated. The fumigation cleans the 
grove of nearly all the insects, including 
scale insects, and it leaves the tree in 
the very best of condition. Apparently 
it puts on an extra growth, but the fly 
increases so rapidly, that when the 
third brood appears, in August, espe¬ 
cially where it comes from neighboring 
groves, the fumigated grove has been 
badly re-infested in August or Septem¬ 
ber. Where there is a very bad infes¬ 
tation of the fly, the killing out of 95 
per cent, at one treatment does not 
seem to be very satisfactory. It is the 
third brood, which appears in August, 
which blacks up the trees, and the time 
elapsing from winter until August 
gives the fly ample opportunity to re¬ 
produce. 
There was one grove fumigated by 
the Tangerine Citrus Association 
which was completely isolated. There 
were, at the time of fumigation, about 
thirty or forty live pupae per leaf. Last 
October there was one pupae to an av¬ 
erage of four leaves. Since then I have 
not made an examination, but, judging 
from what I know about multiplication 
of the insects, I am inclined to believe 
that this crop will also be free from 
fly. In this grove there was 99 4-10 
killed. 
Mr. Skinner: I had an experience of 
that kind with fumigation. I fumigated 
the grove, and it seemed to be pretty 
clean, but my neighbor had a grove 
across the fence that was also infested 
with fly, and the result of it was that 
the flies left his grove and came over 
on my trees. 
Mr. Yothers: This may be one great 
advantage in spraying. It does not 
cost so much as fumigation, and it can 
be done in August, September or Octo¬ 
ber. 
There is another thing which I very 
nearly forgot. At the present time I 
do not know if these emulsions of par¬ 
affine oil can be sprayed on the fruit a 
short time before it is going to be mar¬ 
keted. They stick pretty well and I do 
not know whether they can be washed 
off or not, and consequently I feel if 
the spraying is done as early as pos- 
