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JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 16 
ing of the fruit. Hartzell, 1910, (3) calls attention to the non-ripening 
of grapes and their poor quality due to leaf-hopper infestation. John¬ 
son, 1911, (4) says that foliage badly injured by the grape leaf-hopper 
cannot elaborate the sugar of the fruit. Hartzell, 1912, (5) further 
considers the nature of the injury to grapes by the leaf-hopper as in¬ 
dicated by the quality of grapes from infested vineyards, and in 1913, 
(6) reports on analyses of grapes from vines sprayed with nicotine and 
from non-sprayed vines. Johnson, 1914, (7) again refers to the arrested 
functioning of the foliage by injury due to the grape leaf-hopper and 
says this has a tendency to check the development of the entire vine, 
the size of the crop of fruit is reduced and the quality is rendered in¬ 
ferior by a reduction of the sugar content. DeLong, 1922, (8) referring 
to grape leaf-hopper injury in Erie County, Pennsylvania, says that 
many growers were refused markets for their grapes in 1920 on account 
of the red appearance and the sour flavor of the partially ripened fruit. 
In the report by Hartzell in 1913 he considers that the most im¬ 
portant loss to the grape growers from leaf hopper injury arises from a 
depreciation of the quality of the fruit, that Concord grapes normally 
have a bluish-black color when ripened but that fruit from leaf-hopper 
infested vines has a red appearance, a decided lack in flavor, and shows 
a decrease in sugar content and an increase in acid. He found by 
analyses a consistent gain in sugar content of grapes from a series of 
plots sprayed with nicotine as compared with grapes from non-sprayed 
vines. This increase in the sugar content, due to the control of the 
leaf-hopper varied from a minimum of 8.4% to a maximum of 68.1%. 
The increase in the sugar content of the grapes from the sprayed vines 
varied directly with the amount of leaf-hopper infestation, the lower in¬ 
crease being from vines less infested. The grapes from the vines pro¬ 
tected from leaf-hopper injury had a higher sugar content, a lower 
percentage of acid and a darker color than those grown under identical 
conditions but subjected to the leaf-hopper attack. 
The high leaf-hopper infestation throughout the' vineyards in the 
Pennsylvania section of the grape belt this season emphasized the need 
of control measures for this insect. A nicotine spray was included in 
the spray service of the College. This was applied on six demonstration 
plots in typical locations throughout the section at the time the maxi¬ 
mum numbers of nymphs of the first generation were on the vines. 
It consisted of Jj pint of nicotine sulphate 40% to 100 gallons of w^ater, 
with either resin fish-oil soap (3 pounds) or lime (10 pounds), and was 
