Insects Affecting Sweet Potatoes 



151 



enter it. In this way the upper portion or the end 

 attached to the vine is always attacked first. After the 

 beetles emerge from pupation, they break irregular 



Figure 21. — Cross-section of sweet potato showing injury by 

 sweet potato weevil. Larva in burrow at top; pupa -below; 

 opening to tunnels elsewhere. Enlarged three diameters. 



openings in the skin of the potato which are much 

 larger than either feeding or egg punctures. As the 

 attacks progress and the infestation becomes serious, 

 especially if in storage, the tubers develop a tendency 

 to dry out and shrivel. In some cases of excessive mois- 

 ture or being bruised, the potatoes are affected with 

 brown-rot and often decay, causing the death of the 

 weevils. If the potatoes become extraordinarily hard 

 and dry, the newly emerged adults cannot push their 

 way to the surface and are thus confined in their cells 

 and die. 



M. M. High,^ who has been investigating the weevil 

 1 Farmers' Bull., U. S. Dept. Agr. 



