Pupa 



The pupa is slightly smaller than 

 the mature larva. Its partly devel- 

 oped snout, legs, and wings can be 

 plainly seen, and it has conspicuous 

 eyes. Legs and wings lie folded 

 against or around the body. 



In a week or longer the pupa turns 

 into an adult weevil. 



Adult 



The adult emerges through a hole 

 about the size of a match stem. It 

 feeds on vines, stems, and roots. 



The adult resembles a large ant. 

 It is about one-fourth inch long. 

 Head and wing covers are shiny blue 

 black. The middle part of the body 

 and the legs are bright orange red. 



Adults may live as long as 8 

 months. They become inactive at 

 low temperature, then active again 

 when the temperature rises. 



Adults have been known to fly over 

 a mile in search of food. They prob- 

 ably can fly longer distances. They 

 are seldom seen in flight, however, as 

 long as food is plentiful. 



DETECTION 



You can detect weevil infestation 

 without cutting into sweetpotato 

 plants and without slicing the sweet- 

 potatoes. 



The punctures made by egg-laying 

 females and the feeding punctures 

 made by adults of both sexes are a 

 sign of infestation. They are usually 

 in clusters. To see what they look 

 like, refer to the illustration on 

 page 5, in which the punctures are 

 designated by /. 



Young larvae in a potato begin 

 their tunneling in the punctured 



area, just beneath the skin. If you 

 cut a punctured potato, you will find 

 that the tunnels become larger as 

 they extend inward. Each tunnel 

 contains a larva or pupa unless the 

 insect has completed its cycle in the 

 potato and has emerged. Exit holes, 

 another sign of infestation, are 

 designated by e in the illustration on 

 page 5. 



The main stems of weevil-infested 

 sweetpotato plants become enlarged 

 and pale. If you split stems that 

 have this appearance, you probably 

 will find larvae or pupae (or both), 

 tunnels, and excrement. 



DAMAGE 



Most sweetpotato weevil damage is 

 caused by the larvae as they feed on 

 the sweetpotato roots. 



Even a lightly infested sweet- 

 potato is unfit to be eaten by human 

 beings — both because of the pres- 

 ence of the larvae and because of a 

 bitter flavor that develops. In a 

 severe infestation, hundreds of 

 larvae may feed on one sweetpotato. 



The feeding of larvae and adults 

 on aboveground parts of the plant 

 apparently does not damage the 

 plant enough to reduce yield. 



The most damaging infestations 

 occur in areas where winters are not 

 cold enough to destroy all vegeta- 

 tion on which the weevil feeds. In 

 these areas the weevil can breed 

 throughout the year. 



Heavy infestations occur every 

 year in areas near the South At- 

 lantic and Gulf coasts. In Florida, 

 the weevil has nearly eliminated 

 commercial sweetpotato production. 

 Without an effective State-Federal 



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