INSECTS INJURIOUS TO BEETS AND SPINACH 309 



middle of the abdomen and various mottlings on the prothorax 

 and wingpads. The nymphs become full grown in from sixteen 

 to twenty-two days and the adults again become abundant 

 in August and September; they evidently hibernate as adults, 

 as no more eggs are laid in the fall as far as observed. 



The characteristics of the " curly leaf " are described by Dr. 

 Ball as follows: " 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 roughened appearance on the under side. This is 

 followed by a curling of the edge and a final rolling up of the leaf, 

 the upper surface always being rolled in. As this progresses the 

 smaller veinlets grow still larger and more irregular, knotlike 

 swellings appear at frequent intervals, and in extreme cases 

 little nipple-like swellings appear, extending to a height of nearly 

 one-fourth of an inch. This will be noticed first on 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. . . . 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 recovery and a new set 

 of leaves, though the sugar content remains very low." 



Control. Practical measures of control do not seem to have 

 been very thoroughly tested. With a better knowledge of the 

 hibernating habits of the species, it may be possible to reduce its 

 numbers at that time. Alter the hoppers have appeared in 

 numbers they must be dealt with promptly. "A thorough 

 spraying with kerosene emulsion at a strength of 1 part of the 

 stock solution to 5 parts of water, would destroy most of the 

 insects that it hit, and by using a drag in front of the nozzles to 

 turn the leaves over and cause the insects to jump, most of them 

 would be reached." This would probably need to be repeated 

 in about ten days. Hopperdozers have often been successfully 

 used for collecting various forms of leafhoppers. A modifica- 

 tion of the form used against grasshoppers with a couple of wings 

 extending out on either side of the row and covered with a sticky 

 substance such as " tanglefoot " or that described on page 458 

 would undoubtedly prove effective in collecting the adults, 

 particularly before the females have laid their eggs, when they 

 are more readily caught. A "hopperette " designed by Professor 



