5 
venting almost wholly the ravages of this insect. There was considerable appre- 
hension among the tobacco growers at first regarding the probable injurious 
effects of the kerosene emulsion on the!character of the tobacco. However, a 
careful study of the cured and fermented tobacco from the sprayed plants showed 
that the spraying with kerosene emulsion had not injured the quality or reduced 
the value of the crop. It has been impossible to discover any difference in the 
color, elasticity, or flavor of the treated and untreated tobacco after curing and 
fermenting. On the other hand, the prevention of injury to the tobacco by the 
thrips, by means of the kerosene-emulsion spray, prevented a serious loss to the 
grower. 
The injured tobacco may be fermented sufficiently to even up the color of the 
leaves and darken the white or discolored veins so that the injury will not be 
noticeable, but this severe sweating will darken the leaves to such an extent that 
they can only be classed as dark wrapper. 
For the benefit of those who may apprehend injury to the quality of the to- 
bacco it may be said that the experiments conducted last season indicate that 
when spraying is begun very early in the season it will not be necessary to con- 
tinue it after the crop is about half grown. 
SUMMARY. 
It has been found that this pest can be successfully combated, and 
the following recommendations are therefore made: 
(1) Clean cultivation of the field between crops. 
(2) The planting of other than cereal crops in bordering fields. 
(3) The application of kerosene emulsion (1 part to 10 parts of water) 
with the knapsack sprayer twice a week regularly, as herein described, 
commencing while the plants are in the seed bed. 
Caution.—Care must be taken that the mixture be thoroughly emul- 
sified, else burning will follow its application. 
The emulsion should not be diluted until ready for spraying. 
Spraying must be done in the evening (after 5 o’clock), else the sun’s 
rays will cause a burning of the leaves following the spray. 
Spraying should not closely follow an application of Paris green, and 
when preceding it the plants should be allowed to dry before the Paris 
green is applied. 
Care should be taken not to spray into the bud, so far as it can be 
avoided. 
Approved: 
JAMES WILSON, 
Secretary of Agriculture. 
WASHINGTON, D. C., February 26, 1906. 
O 
