VEGETABLE INSECTS. 



309 



down the stalks to the roots, finally pupating and transforming to 

 beetles at the end of the burrow. 



After this first generation the beetles continue breeding in the 

 roots, and as the complete life cycle consumes only a moth, the pota- 

 toes are soon riddled with burrows and rendered unfit for use. 

 Owing to the practice of leaving the crop in the ground for a long 

 period of time, a mild infestation soon spreads over the entire field. 



Control. — In fighting this pest the best methods are preventive 

 ones. Clean seed or cuttings should be used and they should not 

 be planted in land known to have been infested with the weevil the 

 previous year. Infested potatoes should be fed to livestock. 



i 



SWEET POTATO scARABEE {Euscepes hatttto}) . i 



i 



Another weevil that injures the sweet potato is the so-called 

 ^'scarabee," a small .grayish-black, snout beetle. It is somewhat 

 similiar in habits to the preceding species, spending its entire lifp 

 cycle of thirty days in or on the roots. 



Control. — Control methods are the same as for the preceding 

 species. 



■^ 



h: 



■r 



^ 



Fig. 63. — Sweet Potato Webwonn {PUocrocis irijxuK (ntd). Aioth. 

 Enlarj^jed. (U. S. Bureau of Entoniolofry.) 



SWEET I'O'iATu WEBWOKM {I'Uucrocis iripuHcl cU u) . 



The pale green larvje of this moth feed on the sweet potato foliage, 

 webbing the leaves together to form a shelter in which they live. 



The adult moth is light yellow in color, with black and brown 

 markings on the wings. 



