SMALL, ACTIVE FLEA-BEETLES INJURING FOLIAGE 161 



The Sweet Potato Flea-beetle {Chcetocnema confinis Cr.) 



Soon after sweet j^otato plants are set in the field they begin to show 

 the characteristic work of the sweet potato flea-beetle. Narrow lines 

 are gouged out on the surface of the leaf, at first following parallel 



to the veins, but later running 

 in any direction. At the 

 same time the beetles them- 

 selves will be noticed in in- 

 creasing numbers. They are 

 tiny, active, bronze-colored 



Fig. 172. — The Sweet Potato 

 Flea-beetle. Enlarged and nat- 

 ural size. Original. 



insects, one sixteenth of an 

 inch long. 



In tliree or four weeks the 

 beetles practically all disap- 

 pear, ha\ing migrated to wild 

 plants of related species. The 

 only injury is at the beginning 

 of the season. 

 Dip the plants in arsenate of load when setting them out, immersing 

 the tops but not the roots. Use 1 pound of lead arsenate to 8 or 

 10 gallons of water. In addition, spray the plants with arsenate 

 of lead about ten days later, to protect new foliage. Plants that are 

 set out late will escape serious injury. 



Fig. 171. — W ork of tin- Sweet Potato Flea- 

 beetle. Original. 



