FARMERS BULLETIN 868. 



Fig. 1.— Map sho 



iiig, Ijy shaded areas, approximate di-stribution 

 of the Colorado potato beetle. 



nearly full grown, very little of the potato plants except denuded or 

 bare stems and dry and black foliage remains. Afterwards the beetles 

 and larvae attack eggplant and other plants of the potato family. 



The distribution of the potato beetle (see fig. 1) covers practically 

 the entire Ignited States from the Great Plains eastward to the 



Atlantic coast, ex- 

 cepting the extreme 

 southern parts of 

 Florid a, iUabama, 

 Mississippi, and Lou- 

 isiana. In Texas it 

 occurs in the trop- 

 ical region bordering 

 the Gulf of Mexico. 

 It also occurs in re- 

 stricted parts of 

 Washington, Oregon, 

 Idaho, Arizona, Mon- 

 tana, Wyoming, Col- 

 orado, and New Mexico. In a few of these States it is present, but 

 not as a pest — for example, in some regions of Colorado, where it 

 feeds on a wild plant belonging to the potato family. It is constantly 

 extencUng its territory as a pest. 



The potato beetle is weU known to aU growers of potatoes. The beetle 

 is robust and yeUow, and its wing-covers are ornamented with 10 black 

 lines (see fig. 2, a; fig. 3, a). It is tln-ee-cighths of an inch long. The 

 "slugs" (young, orlarva>) (fig. 2, h; fig. 3, c, c, d, d) are dark red when 

 first hatched, becoming paler with larger growth. They are slimy, soft 

 in texture, and of disgusting appeai*ance. The pupa, or resting stage, 

 is shown at c in figure 3. The eggs (fig. 3, 6, h) are orange colored and 

 are deposited in masses. 

 The Colorado potato 

 beetle feeds on practi- 

 cally all plants of the 

 potato family, attack- 

 ing potato, eggplant, 

 tomato, ground cherry, 

 and Jimson weed, be- 

 sides other weeds of 

 this family. 



In the more northern range of this insect there is probably only one 

 generation a year, or, exceptionally, two generations. Farther south- 

 ward three more or less complete generations occur. This insect 

 pest passes the winter in the beetle stage from a few inches to several 

 feet underground. 



-Colorado potato beetle: a, Beetle; 

 c, pupa. Enlarged. 



slug"; 





