THE GEAPE LEAFHOPPER IN THE LAKE EEIE VALLEY. 
berries in the cluster, and in a deficiency in the sugar content of the 
fruit. For these reasons the aggregate injury by this pest during the 
season of 1912 was fully as great as in that of 1911. 
Thus far mention of the destructiveness of this pest has been con- 
fined to the vineyard areas of the Eastern States. For more than 25 
years this species, Typhlocyba comes, including a western variety, 
coloradensis (fig. 5), has caused an enormous amount of injury to the 
grapevines in the vineyards of California, where it has been recorded as 
an injurious grapevine pest since 1875. Prof. H. J. Quayle, in Bul- 
letin 198 of the California Experiment Station, states in regard to its 
destructiveness that "with the exception of the Phylloxera, the vine 
hopper is undoubtedly the most destructive insect pest of the vine in 
the State. It is more uniformly present than any other insect attacking 
the vine, and each year in some parts of the 
State it occurs in very great numbers, and 
in such sections it levies a heavy tax upon 
the vineyard interests. " 
Thus it is evident that, taken in the aggre- 
gate, the injury sustained by the vineyard 
industry of the East and the West must 
amount to an enormous sum. It should be 
remembered, too, that the injury caused by 
this pest is not confined to the crop of a 
single season. It frequently happens that a 
heavy infestation of one or two seasons' 
duration may so stimt the growth of the vine 
that its full fruiting capacity may be re- 
duced for several seasons. In fact, if special 
efforts for the resuscitation of badly injured 
vines are not undertaken they may never re- 
gain their former productive value. Hence 
the loss to the vineyardist not only consists 
in the crop shrinkage, but also in the additional cost of the fertiliza- 
tion and care required to get the vine back into full bearing condition. 
Fig. 5. — A western variety of the 
grape leafhopper, Typhlocyba 
comes var. coloradensis: Adult. 
Greatly enlarged. (Author's 
illustration.) 
ALLIED SPECIES. 
In the region known as the Chautauqua and Erie grape belt, which 
includes a narrow strip of territory stretching along the southern 
shore of Lake Erie from Silver Creek, N. Y., to Harbour Creek, Pa., 
there are approximately 40,000 acres of vineyard, over 90 per cent of 
which are of the Concord variety. The species of leafhopper found 
in injurious numbers in the vineyards throughout this region is 
Typhlocyba comes. Although occasional specimens of other varie- 
ties and species may be found, their presence in numbers sufficient to 
10037°— Bull. 19—14 2 
