SPRAYING AGAINST THE GRAPE LEAFHOPPER. 5 
warm afternoons of early autumn the air will be filled with thousands 
of these little creatures drifting somewhat aimlessly on the light 
breeze and causing considerable annoyance by get- 
ting into the eyes, ears, and mouth of the beholder. 
A close observation of the underside of the leaves 
of grapevines at this season is likely to reveal the 
immature or nymphal stage of the insect (fig. 2). 
These vary greatly in size, from those just hatched 
to the full-grown nymphs with well-developed wing 
Fic. 2.—The grape 
pads (fig. 3), but they have always the same general = ieafhopper: 
: Ag = eo a r Nymph of the first 
form. These leafhoppers belong to the same order "ii! areas 
of insects as do the scale insects and the plant-lice — enlarged. (Origi- 
and secure their food by sucking the juices from the — ™*"? 
plant in much the same manner as the mosquito sucks blood from an 
animal. A knowledge of this method of taking food is of the great- 
est importance from an economic standpoint, since insects which take 
their food in this way are usually amenable to a spray application of 
an entirely different quality from that which 
is used in the case of insects which chew or 
masticate their food. Sucking insects are 
usually combated by the use of some caustic 
or smothering substance which must come in 
direct contact with the outside of the body 
of each individual, practically at the time 
of application and in sufficient quantity and 
strength to effect its almost immediate de- 
struction; whereas, in the case of the chew- 
ing insect a stomach poison must be applied, 
not to the body of the insect, but to the sur- 
face of that portion of the plant or fruit 
By eee Srape leathop= non which the imsect feeds. 
per: Fully developed 
nymph of the fifth molt. The adults and the nymphs of the grape 
ota enlarged. (Origi- Jeafhopper feed upon the underside of the 
grape leaf and by sucking the juices there- 
from cause it to take on a yellowish, mottled appearance (fig. 4), 
which later turns brown, and where the infestation is heavy the leaves 
dry out and become functionless before the fruit is mature. (See 
fig. 5.) 
LIFE HISTORY. 
HIBERNATION. 
The grape leafhoppers pass the winter as winged adults, which 
migrate from the vines during October. By the time the grapes are 
harvested only a small percentage of the adults will be found upon 
