UV 
Contribution from the Bureau of Entomology, L. O. Howard, Chief. 
June 15, 1914. 
ARSENATE OF LEAD AS AN INSECTICIDE AGAINST THE TO- 
BACCO HORNWORMS IN THE DARK-TOBACCO DISTRICT. 
By A. C. Morean and D. C. Parman, 
Entomological Assistants, Southern Field Crop Insect Investigations. 
INTRODUCTORY. 
In the dark-tobacco districts of Kentucky and Tennessee tobacco 
hornworms (Phlegethontius quinquemaculata Haw. and P. sexta Joh.) 
are the ever-present and most serious problem of the tobacco 
erower. Ten to twelve 
years ago, when labor was 
plentiful, cheap, and effi- 
cient, ‘hand worming” was 
found to be economical and 
effective in combating this 
pest. However, during the 
last six or eight years hand 
worming has become too 
costly, because of the great 
scarcity and inefficiency of 
labor, and the growers have 
been forced to employ an 
insecticide. At the time insecticides were first used Paris green was 
found to be the safest and most efficient. Nevertheless, there has 
always been complaint of frequent serious burning of tobacco as a 
result of its use. To find a safe and effective insecticide has been 
one of the main lines of investigation during the past five years. 
Arsenate of lead (diplumbic) has been found to meet the requirements. 
Fic, 1.—Map showing distribution of the tobacco hornworms 
in the United States. 
NECESSITY AND ADVANTAGES OF THE USE OF AN INSECTICIDE. 
The effect of the scarcity of labor in bringing about the use of 
an insecticide upon tobacco has already been explained. In addi- 
tion to this necessity of using a poison, the much greater efficiency 
Note.—This bulletin is intended to assist the tobacco growers of Kentucky and Tennessee and the 
_ adjoining States in combating a troublesome pest. 
42497°—Bull. 595—14 
