﻿BULLETIN OF THE 



i 



No. 19 



Contribution from the Bureau of Entomology, L. O. Howard, Chief 

 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, Typhlocyba 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 subsjrinosus 

 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. Greatl y enlarged. 

 (Original.) 



