4 
into the bud more than is necessary, else burning is likely to follow. 
As the plants get larger this can easily be avoided. It will be found 
well to apply the Paris green and meal on the morning following the 
spraying, when possible. 
HOW TO USE THE EMULSION. 
One part of the stock emulsion to 10 parts of water has been found 
to be effective. The emulsion may be readily diluted to the required 
strength, in large quantities, in barrels or casks set near the rows to be 
sprayed. In the experiments at Quincy, Fla., the kerosene was found 
to separate from the soap to some extent when left standing; it will, 
therefore, be safer not to dilute it until ready to spray. 
The tobacco may be sprayed during the day until 6 inches in height, 
for even if burning should take place the leaves injured will be those 
that would soon drop off. As the plants get larger, however, it has 
been found necessary to spray in the evening, shortly after 5 o’clock. 
On very bright, hot days it will be necessary to wait until a little later. 
On large plantations this gives insufficient time during daylight, and 
spraying after dark has been found necessary. In so spraying alter 
dark, the use of two pumps to a row, one on each side, preceded by a 
boy with a lantern or torch, is a very satisfactory and economical method 
of application. Care should be taken that the spray be distributed over 
all the leaves, as it must come in contact with the thrips when sprayed 
in order to be effective. 
COST OF SPRAYING. 
The applications necessary to keep the pest in check will be found 
to vary considerably, depending upon the amount and period of rain- 
fall. It seems improbable that two applications weekly will be found 
necessary for the maximum period of ten weeks. Even if found neces- 
sary, it is roughly estimated that the expense will not exceed $20 per 
acre. 
Apparatus.—The use of a knapsack sprayer has been found to be 
the most practical method of applying the emulsion. These sprayers 
can be purchased at prices ranging from $5 to $15. 
SUPPLEMENTARY NOTE. 
During the work on this insect the writer was associated with Mr. 
W. W. Cobey, tobacco breeding expert of the Bureau of Plant Industry, 
from whom valuable advice and suggestions were received. 
Mr. Cobey writes as follows regarding the effect of spraying on the 
character of the tobacco: 
It is the opinion of the writer, after a careful comparative study of the treated 
and untreated tobacco, that the use of kerosene emulsion on tobacco, when care- 
fully prepared and applied at the proper time, under favorable conditions, is in 
every way practical and can be profitably employed by tobacco growers in pre- 
