44 SOME INSECTS INJURIOUS TO TRUCK CROPS. 
and consisting of a dozen or more leaves. Over another beet of the 
same size a check cage was placed. Seventeen days later the eggs 
had just begun to hatch, and already the beet in the cage without any 
hoppers was nearly twice the size of the first one. The beet on which 
were the leafhoppers continued to grow for a week or more, then 
practically stood still, and on the seventeenth day it was apparently 
smaller than when examined five days before. Seven days later a 
large number of nymphs had hatched out, the outer leaves were dead, 
and the rest looking sickly; ten days later than this the cage was 
examined again and the beet was dead and dry, while the beet in the 
check cage had again doubled in size. Twelve leafhoppers and their 
eggs stopped the growth of a beet in less than two weeks, and they, 
together with their progeny, killed it in less than two weeks more. 
The same number of adult specimens of Agallia, Nysius, or Empoasca 
would scarcely have made an impression on a beet of that size. 
CHARACTERISTICS OF " CURLY-LEAF." 
The first symptom of " curly-leaf " or " blight " of the beet is a 
thickening of all the smaller veinlets of the leaf, giving it a rough- 
ened appearance on the underside. This is followed by a curling of 
the edge (PL III, fig. 1) and a final rolling up of the leaf (PL I, fig. 
I, j; PL II, figs. 2, 3; PL III, fig. 2), the upper surface always being 
rolled in. As this progresses the small veinlets grow still larger and 
more irregular, knotlike swellings appear at frequent intervals (PL 
III, fig. 2), and in extreme cases little nipplelike swellings appear, 
extending to a height of nearly one-fourth of an inch (PL I, fig. 1, k) . 
This will be noticed first upon a medium-sized leaf, gradually 
spreading to the younger ones, while at the same time the beet almost 
stops growing and a large number of fibrous roots are sent out (PL 
II, fig. 1). These roots are not confined to two irregular lines as in 
a healthy beet. The beet often continues in this way throughout the 
season, in bad cases it shrivels and dies, while in a few instances there 
is a partial recover} 7 and a new set of leaves, though the sugar content 
remains very low. 
Many of the species of this genus of leafhoppers produce a 
discoloration or distortion of the leaves of their food plant. This 
appears to be of the same nature as the work of the gall-forming 
species, and is a process little understood. The wrinkling and folding 
of the leaves by some of the species is very similar in appearance to 
the work of some gall-forming aphides. Some species also produce 
a change in color similar to that produced in many galls. 
In the case of Eutettix strobi (PL I, fig. 2 «, b) and E. scitula on 
the Chenopodium or on the sugar beet and of E. nigridorsum and E. 
straminea (PL I, fig. 6) on the Helianthus the discoloration appears as 
