THE ORANGE THRIPS. 13 
possible to save the tender foliage and axillary buds and to promote 
a growth of 1 to 2 feet more on the sprayed trees than on those 
unsprayed. 
Spray Injury. 
While no actual spray injury, immediate or cumulative, developed 
from the use of distillate-oil emulsion and blackleaf tobacco extract 
at the strengths indicated above, the uncertainty of this combination 
as compared with the lime-sulphur and blackleaf tobacco extract 
led to the adoption of the latter as a spray for demonstration work 
during the season of 1910. 
RECOMMENDATIONS. 
In view of the success attained in reducing injury to fruit and 
foliage by the orange thrips, it is believed that it will be possible to 
control this species in normal seasons with four applications of lime- 
sulphur combined with blackleaf tobacco extract. 
TIME OF APPLICATION. 
Three of the treatments should be made in the spring to free the 
fruit and spring growths of foliage from, in jury, since the more 
severe marking of fruit is done while the fruit is small. The fourth 
treatment should be made in August or September, according to sea- 
son, for the protection of the later growths of foliage, and should be 
timed to catch the thrips when numerous, but before the leaves show 
much curling. The three spring applications should be made about 
as follows: 
First. Just after most of the petals have fallen from the blossoms. 
Second. Ten to fourteen clays after the first. 
Third. From three to four weeks from the time of the second treatment. 
The dates for spraying in any given season must be timed by the 
abundance of thrips. 
SPRAY DILUTIONS. 
Lime-sulphur solutions should be diluted according to density. 
In the homemade product this may be determined by the use of a 
Baume or a specific gravity spindle. The density of the commercial 
product will be stated by the manufacturer or may be obtained b}^ 
the use of the spindle. 
Lime-sulphur solution of a density of 33° Baume should be diluted 
at the rate of 1 volume to 75 volumes of water ; that of a density of 
36° Baume should be diluted at the rate of 1 volume to 86 volumes 
of water. Therefore the formula for orange-thrips spraying 
would be: 
