THE GRAPE-VINE LEAF-HOPPERS. 35 
“On May 20th a mixture of kerosene and water was ap- 
plied with a knapsack sprayer having a special arrangement 
for mixing the two liquids without previously making an 
emulsion. This liquid was used in the proportion of one 
part of kerosene to fifteen parts of water, and the vines were 
thoroughly moistened with it. During the spraying the leaf- 
hoppers rose in swarms and many fell to the ground, but 
the greater part of these recovered and flew away to return 
in the course of halfan hour. A few were rendered inactive 
and appeared paralyzed for a time but very many of these 
recovered in less than half an hour. The mixture seemed to 
produce no permanent effect upon the insects, simply be- 
cause the integument of these minute beings is very smooth. 
To remove the offensive fluid the insects used their spiny 
hind-legs very diligently and with success. 
A solution of tobacco-soap in the proportion of two 
ounces of the soap to one gallon of water, and another one 
of one-half pound of whale-oil-soap to the same amount of 
water was applied. Mr. Reel reported on June 10th that 
neither had been of much use, and that even a few hours 
after the application but very little difference could be de- 
tected between plants treated and not treated. 
On July 3rd another trip was made for the purpose of 
trying a tobacco-extract sold as ‘‘Scabcura Sheep-dip.”’ 
This mixture was applied with a knapsack sprayer in two 
different strengths; one row of vines was thoroughly 
sprayed using two ounces of the extract to one pailful of 
water, and another row was sprayed using four ounces of 
the extract. The effect was immediate and at the end of 
two hours but very few of the pests could be seen on the 
plants. On Aug. 25th Mr. Reel reported as follows: ‘I am 
pleased to be able to report that the grape-vines upon which 
you experimented show a much better foliage than 
the adjacent rows—although the hoppers appear on them to 
some extent, the foliage is not so badly browned. Iam satis- 
fied that by spraying in the spring, while the leaves are not 
too thick, it might drive them away. The stronger solution 
is by far the most effective one.” The action of 
this extract is almost wholly that of a repellant, and 
