INSECTS INJURIOUS TO BEETS AND SPINACH 121 



insects, white grubs and wirewornis, are at times injurious to 

 the roots, and root-aphides injure the roots so as to render 

 them comparatively useless. 



FLEA-BEETLES AND LEAF-BEETLES 



As flea-beetles are among the most troublesome sugar-beet 

 pests from their early occurrence and the rapidity with which 



bb b 



Fig. 75.— Spinach flea-beetle, a. Beetle; b, egg mass, showing mode of escape of larva 

 at right: 66, sculpture of egg; c, full-grown larva; d. pupa; e, newly-hatched larva;/, 

 abdominal segment of same, a, c, d. Five times natural size; 6.. e, more enlarged; bb, f, 

 still more enlarged. (Author's illustration, U.S. Dept. Agr.) 



they work, they may receive first mention, especially as no less 

 than twenty forms have been observed attacking this plant 

 Some of these are widely distributed; others are local. Most 

 farmers are familiar with flea-beetles, better known perhaps as 

 "fleas," and it will be unnecessary to enter into detail in regard 

 to more than one species. 



The Spinach Flea-beetle (Disonycha xanthomclcena Dalm.). — 

 This flea-beetle (fig. 75) is black with a reddish-yellow thorax. 

 It appears early and, like other species of its kind, works 



