BULLETIN OF THE 
No. 19 
Contribution from the Bureau of Entomology, L. O. Howard, Chief. J 
January 24, 1914. 
(PROFESSIONAL PAPER.) 
THE GRAPE LEAFHOPPER IN THE LAKE ERIE 
VALLEY. 
By Fred Johnson, Agent and Expert. 
INTRODUCTION. 
For several years past the grape leafhopper, TypJilocyba comes Say 
(fig. 1) , has been increasing in destructive numbers throughout the vine- 
yards of the Lake Erie Valley, and since 1910 it has been recognized 
as a serious menace to the grape-growing interests of that region. 
During the years 1910 and 1911 vineyard experiments for the con- 
trol of this pest were conducted by the members of 
the field laboratory force stationed at North East, 
Pa. , working under the direction of Mr. A. L. Quaint- 
ance, in charge of Deciduous Fruit Insect Investiga- 
tions of the Bureau of Entomology. Owing to the 
pressure of work involved in the conduct of numer- 
ous vineyard experiments against this pest, and also 
against the rose-chafer (Macrodactylus subspinosus 
Fab.) and the grape-berry moth (Polychrosis 
viteana Clem.), it was impossible to make a de- 
tailed study of the life history of the grape leaf- 
hopper during those seasons. As most of these 
field experiments had been brought to a success- 
ful termination at the close of the season of 1911, 
the investigations for the season of 1912 were 
devoted largely to life-history studies of this pest. 
In this work, which was carried on at the field 
laboratory at North East, Pa., the writer was 
assisted by Mr. E. R. Selkregg in the recording of the data bearing 
upon the various stages of the life history of the insect. 
The following pages contain a record of these life-history studies, 
together with a short historical account of the part this insect has 
played as an enemy of the grapevine in other grape-producing sec- 
tions of the United States .and Canada. A detailed account is given 
10037°— Bull. 19—14 1 
Fig. 1. — The grape leaf- 
hopper ( Typhlocyba 
comes): Adult, winter 
form. Greatly enlarged. 
(Original.) 
