﻿THE CRAPE LEAFHOPPER IN THE LAKE ERIE VALLEY. 7 



presence or its injury to the foliage of the vines. During these 

 periods serious injury to the vines or to the crop yield is confined to 

 a few rows of vines adjacent to ravines, woodlots, or rough pasture 

 lands. This limited amount of injury usually attracts little attention 

 and no attempt is made by the vineyardist to hold the insect in check. 

 Then a series of seasons favorable to its development may occur, 

 and there appears to be a steady yearly increase in numbers and fur- 

 ther encroachment into the infested vineyards. Finally it becomes 

 so abundant and thoroughly disseminated throughout the vineyard 



Fig. 4. — Grape leaf in advanced stages of injury. Areas between veins have turned a reddish brown. 



(Original.) 



area, and its destruction is so obvious, that it attracts general atten- 

 tion, and the so-called "outbreak" causes considerable alarm among 

 the vineyardists. Such "outbreaks" have been recorded from many 

 States, as is indicated in the quotation from Slingerland under the 

 caption "Origin and distribution." The same author states that 

 "outbreaks" have occurred at frequent intervals in various parts of 

 the State of New York as follows : 



In Wyoming County in 1860; in the Hudson Valley in 1865, 1867, 1882, 1887, and 

 1897; on Crooked Lake in 1880; in Jefferson County in 1887 and 1888; in central New- 

 York in 1895 and 1899; and in Chautauqua County in 1900 to 1904. 



