SPRAYING AGAINST THE GRAPE LEAFHOPPER. 5 
results to check the development of the foliage and to retard the 
growth of those new shoots which spring from. the canes near the 
lower wire of the trellis. This early retardation of growth is more 
important than would at first appear, for it is highly desirable that 
these new shoots springing from the canes near the lower wire of the 
trellis should make a thrifty growth during the early part of the 
season, since it is from them that canes for bearing the next season’s 
crop of fruit are selected. This feeding of the overwintering adult 
“hoppers ” continues for several weeks; in fact, many of them may 
remain upon the vines 
until some of the new 
generation has ma- 
tured. 
THE EGG STAGE. 
Egg laying by the 
overwintering fe- 
males does not com- 
mence in the vine- 
yards of the Lake 
Erie Valley until 
about June 1, after 
the adults have been 
feeding upon the 
vines for several 
weeks. The eggs are 
deposited on the un- 
derside of the leaves. 
They are tucked un- 
der the skin indis- 
criminately as to lo- 
cation on the leaf and Fie. 5.—Grape leaf showing final result of attack by the 
are very diffieult to grape leafhopper; leaf withered and brown before the 
fruit is mature. (Original.) 
locate on those varie- 
ties possessing a heavy pubescence, as is the case with the Concord. 
The egg stage covers a period of about 10 days to 2 weeks. The period 
of egg deposition is obviously a long one, since newly emerged nymphs 
are present upon the foliage from the middle of June until late in 
October. Observations indicate, however, that the maximum deposi- 
tion must occur during the last three weeks in June and the first week 
in July, since the period when there is a maximum number of nymphs 
upon the leaves is included in a period from the last week in June 
until about August 1, at which latter date many fully developed 
nymphs are making their final molt. 
71419°—Bull. 9712-2 
