CHAPTER XV 



INSECTS INFESTING THE SWEET POTATO 



The sweet potato is a staple from New Jersey and Maryland 

 southward. It is seldom that plants are not more or less in- 

 fested by insects, and of these the tortoise beetles are con- 

 spicuous because of the holes which they eat in the leaves. As 

 the crop is started under glass and transplanted, it is subject to 

 attack by cutworms and similar insects. There are several 

 other defoliators, blister beetles, the larvae of sawflies, a hawk- 

 moth and others; flea-beetles sometimes do considerable injury, 

 while in the extreme South the sweet-potato root-borer is be- 

 coming an important pest from its destruction of the tubers. 

 In spite, however, of a considerable number of insects which 

 attack this plant, it does not, on the whole, suffer very material 

 injury save in restricted areas and in years when certain pests 

 are abnormally abundant. The root-borer, however, threatens 

 to be a permanent pest in the Gulf region. 



The Sweet-potato Root-borer {Cylas formicarius 01.).— In- 

 jui^y by this insect in North America was first noticed about 

 1877 near New Orleans, La., when it was claimed to threaten 

 the destruction of the sweet potato crop of the country, a pre- 

 diction which was, happily, not verified until about 1903. 



The adult is a weevil of ant-like form except for the long 

 snout which it possesses (fig. 150, 0) . It is small, about one- 

 fourth of an inch in length, including the snout, the elytra are 

 shining dark blue, the head and snout darker blue, and the 

 thorax and long legs shining red. The larva (b, c) when grown 

 is about one-fourth of an inch long, white, with brown head and 

 darker mouth-parts. 



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