FLEA-BEETLES 



325 



black, with each wing-cover marked with a wavy yellowish 

 stripe, narrowed in the middle and incurved at each end (Fig. 

 204). The beetles are most destructive to cabbage plants be- 

 fore the fourth leaf has appeared or during the first week after 

 they come up. They gnaw pits in the leaves but do not eat out 

 holes except in very thin leaves. Young cabbage, turnip and 

 radish plants are often killed in this way. The females deposit 

 the minute, oval, whitish eggs at the base of the plant in irreg- 

 ular excavations gnawed out in the root near the crown. The 

 larvae feed on the roots of cabbage and 

 radish and in New York have been found 

 especially abundant on the roots of the 

 wild mustard. The larv^ eat off the 

 smaller roots and riddle the main one 



sometimes excavating the 



The full-grown larva is 



in length, whitish with a 

 light brown head. In Illinois the larvse 

 are present in late May and June and 

 give rise to a brood of beetles in August. 

 The over-wintered beetles mostly dis- 

 appear in June and in the North turnips sowed after this date 

 are likely to escape injury. In North Carolina a second brood 

 of larvae has been observed on turnips in October. In Illinois 

 there is said to be but one generation annually but in North 

 Carolina there are at least two. 



Cabbage plants in the seed-bed are very liable to injury 

 by this flea-beetle. They may be protected by screening the 

 beds with cheesecloth as recommended for the cabbage root- 

 maggot (page 35). 



with tunnels, 

 entire root, 

 about i inch 



Fig. 204. — The striped 

 cabbage flea-beetle 

 (X 13). 



Reference 

 Shimer, American Naturalist, 2, pp. 514-517. 1869. 



