INSECTS AFFECTING THE POTATO. 



INJURING THE STEM. 



The Potato Stalk-weevil. 



Trichobaris trinotata. 



Potato stems are sometimes infested by a whitish 

 or yellowish-white, footless grub, about a quarter of 

 an inch long, which burrows in the heart of the 

 stalk, especially near the ground, and causes the 

 plant to wilt and die. This is the larva of a small, 

 grayish snout-beetle, called the Potato Stalk-weevil, 

 the females of which deposit their eggs, singly, in a 

 slit made for the purpose in the stem, slightly above 

 the soil surface. In a few days the egg hatches into 

 a little grub that burrows down the center of the 

 stem toward the root. A few weeks later, still 

 within the stalk and slightly below the surface of the 

 ground, the larva pupates, and late in summer or 

 early in autumn it emerges as an adult weevil. This 

 weevil passes the winter under whatever protective 

 covering it may find, and the following season starts 

 another generation by depositing its eggs in the 

 potato stalks. 



The injuries of this insect are sometimes quite 

 severe. In Iowa, during the season of 1890, Profes- 

 sor C. P. Gillette estimated that 75 per cent, of the 

 potato plants were infested by it. It is a widety dis- 

 tributed species. 



