58 
FLORIDA STATE HORTICULTURAL SOCIETY. 
the latest growth. A few of the old 
leaves had fallen, but I do not think 
that is a serious objection. About two 
weeks after the spraying had been done 
I visited this grove and I thought that 
all those trees which were sprayed 
with the oils—both with the formulae 
and proprietary articles—had leaves of 
a slightly lighter shade of green than 
those sprayed with lime sulphur and 
kerosene emulsion, and also those 
sprayed with i per cent of IV had 
leaves of a lighter shade of green than 
those where one-half of i per cent, had 
been used. I was unable to see any 
difference in the effect on the leaves 
where distillate, a light oil, had been 
applied, and where the heavy paraffine 
oil, Junior Red Engine oil, had been 
used. This was very discouraging. I 
thought at the time that the application 
of any oil to the tree might so interfere 
with the functions of the leaves as 
to make it necessary to abandon our 
recommendations. I called the atten¬ 
tion of several growers, and they did 
not seem to think the difference in 
color was anything serious. About a 
month after the spraying I visited the 
grove and am glad to say that this 
difference has almost entirely disap¬ 
peared. At present I do not know 
whether continued application of any 
of these oils, that is, several times dur¬ 
ing the same year, will be injurious. I 
would advise considerable caution, 
however, in this matter. 
No doubt it will be of interest to the 
orange growers to learn of the spray¬ 
ing of a large grove with one of these 
paraffine oils. This grove was sprayed 
with Formula IV, 1-50 or 1 per cent, 
of oil. The insects were in the young 
stages—mostly second instar or larval 
stage. The grove consisted of 2,600 
large seedlings and 1,600 three-year- 
old budded trees, and these were 
sprayed with two machines in 16 days, 
from April 3 to April 20. It was a good 
day’s work for one machine to spray 
115 large seedlings, but 600 or 700 of 
the small budded trees could be sprayed 
in a day with one machine. The insec¬ 
ticide cost, including freight, $135.00. 
The total cost was $409.00, or 9 7-10 
cents per tree. It took about the same 
amount of spray material for 75 bud¬ 
ded trees as it did for 16 of the seed¬ 
lings. If this is taken into considera¬ 
tion the price per tree would be about 
13 1-2 cents. The trees required 32,250 
gallons, averaging 8.4 gallons per tree. 
The seedlings averaged about 13 gal¬ 
lons each. At the present time the 
sooty mold is pretty well loosened up, 
and after one or two good rains I think 
the grove will be entirely free. I made 
a hasty examination to determine the 
percentage of insects killed and found 
it to be approximately 95 per cent. It 
is the intention to spray this grove 
again after the third brood of flies dis¬ 
appears. 
This brings up the subject of how 
often to spray. Of course, it is gener¬ 
ally understood that the killing of 95 or 
96 per cent, of the fly once during the 
year does not mean so much, after all. 
Especially is this true if done early in 
the spring or summer. They come 
