SPRAYING AGAINST THE GRAPE LEAFHOPPER. iL 
this spraying, and Mr. Pierce is confident that under favorable condi- 
tions the cost per:acre could be materially reduced. 
A portion of the vineyard on the farm of Mr. John Higgins which 
has been seriously infested by the grape leafhopper, to which he 
attributes the shrinkage of several thousand baskets of fruit during 
the past two or three seasons, was treated in the same manner as the 
vineyard of Mr. H. H. Harper. 
On three blocks, however, the strength was varied as follows: 
Blackleaf tobacco extract, 1 gallon to 75, to 100, and to 150 gallons of 
water. As far as could be observed the dilution to 150 gallons of 
water was as effective as that to 75 gallons. All of the applications 
mentioned above were made before any of the nymphs had completed 
-the final molt, and all of them were highly effective in reducing the 
number of the nymphs to a point where their injury for the remainder 
of the season was very slight. On all of these treated blocks the 
foliage remained dark green and growth continued until quite late in 
the season, whereas in adjacent infested and unsprayed vineyards the 
foliage commenced to turn brown before the fruit was ready to pick. 
In fact, the sprayed and the unsprayed portions of these vineyards 
were readily distinguished within two or three weeks after the appli- 
cation was made, and the difference in the condition of the foliage 
became more marked as the season advanced. 
Plate II shows photographs of vines taken in the experimental 
vineyard of Mr. H. H. Harper. Figure 1 is an unsprayed vine, and 
shows the exposure of the fruit by loss of a part of the foliage and 
also the withered condition of the leaves still attached to the vines, 
as a result of grape leafhopper injury. Figure 2 shows the perfect 
condition of the foliage on a vine growing in the adjacent row which 
was sprayed with tobacco extract. There is just as much fruit on 
the vine shown in figure 2 as on the vine shown in figure 1, but 
owing to the perfect condition of the foliage it can not be seen. The 
injurious effect of this pest upon the crop yield is cumulative. Asa 
result of several seasons of infestation the cane growth of the vine 
is stunted during the growing season, and the final outcome is a 
sickly vine producing small clusters of poorly ripened fruit. 
The owners of all of these vineyards were satisfied with the results 
of these experiments, and are planning to treat their entire vine- 
yards with the tobacco extract next season if the insect is present in 
them in injurious numbers. 
As the season advanced toward August 1, vineyardists began to 
observe the serious nature of the injury wrought by this pest. Most 
of them were unprepared to treat it, however, since they had no 
spraying material on hand, and many of the nymphs were passing 
from the last molt and developing wings. Nevertheless it was pos- 
sible to undertake another experiment on the vineyard of Mr. Charles 
