THE HOP FLEA-BEETLE. 
77 
brown freckles as the leaf grows and expands, the skin at this point 
in time becoming torn and frequently showing holes. When the 
beetle occurs in moderate numbers the leaves (fig. 14) become riddled, 
as by fine shot, the punctures being most obvious after the plants ha ve 
made some growth. In its attack on hops it frequently causes the 
leaves to look like a mass of network or more or less completely 
strips the vines of leaves, as shown in figures 15 and 16. As is the 
case with flea-beetles in general, this species does most harm to young 
plants. When the beetles occur in considerable numbers they are 
capable of doing great damage in a comparatively short time, com- 
pletely devouring 
the young and 
tender leaves as 
fast as they come 
up. 
Injury is most 
noticeable on 
hops, sugar beet, 
rhubarb, and some 
other vegetables. 
The beetle is a 
general feeder, the 
list of its food 
plants including, 
among vegetables, 
rhubarb, beet, cu- 
cumber, turnip, 
radish, cabbage, 
mustard, and po- 
tato. It feeds also 
on hops, red and 
white clover, nettle, dock (Ivimiex), lamb's-quarters (Chenopodium) , 
pigweed and tumbleweed (Amaranth/us retroflexus and A, yrachins). 
hedge mustard, and common wild-growing black mustard. The prob- 
abilities are that, as all of these plants are affected by the adult beetles, 
a considerable proportion of them serves as food for the larvae. On 
this head Mr. Quayle has written that the eggs, larvae, and pupae 
were taken at a depth of from three to six inches from the surface 
of the ground in hop fields and that the larvae apparently feed on the 
roots of hop as well as those of other plants growing in the yards. 
Since it is well known that the beetles occur in other regions where 
hops do not grow there must be other larval food plants. It would 
be interesting, and is important, to ascertain exactly what plant, or 
plants, is the favorite with the larvae. 
Fig. 14. — Hop leaves, showing work of flea-beetle. (Original.) 
