386 INSECT PESTS OF FARM, GARDEN AND ORCHARD 



larva is rather interesting. At each molt, the fseci-fork of the 

 last stage is held upon the new fseci-fork, and in this way those 

 of the different stages are telescoped, the one inside the other, 

 and the stage of growth of the larva may be readily determined 

 by the number of cast skins held on the fork. From the like- 

 ness of this burden to a pack, the larvae are often known as 

 " peddlers." In order more firmly to bind the excrement and 

 cast skins to the fork, the larvae fasten them together by a fine 

 network of silken threads, which are attached to the spines at 

 the sides of the body. When fully grown the larva fastens itself 

 to a leaf, its skin splits open along the back, and from it comes 

 the pupa, which is held to the leaf by its caudal fork, which is 

 securely encased in the fseci-fork of the larval skin. About a 

 week later the adult beetle emerges, eats for a few days and then 

 disappears from the sweet-potato patch until the following spring, 

 doubtless feeding on morning glory until it enters hibernation. 



Control. From the similarity of their life history and habits 

 all of these species may be treated at once. As the beetles do the 

 most injury just after the plants are set, they should be dipped 

 in arsenate of lead when setting, as advised for the flea-beetle. 

 If this has not been done or if the beetles are injurious in the 

 forcing bed, the plants should be thoroughly sprayed with arse- 

 nate of lead, 3 pounds. per barrel or Paris green, J pound per 

 barrel with \ pound of freshly slaked lime. 



The Sweet-potato Root-borer * 



Since 1890 sweet potatoes have been seriously injured in parts 

 of Texas and Louisiana by a small white grub which bores into 

 the stems and tubers both in the field and in storage, but strangely 

 it has not spread elsewhere in this country. In Texas the worst 

 injury has been in Calhoun and neighboring counties along the 

 Gulf Coast where extensive growing of sweet potatoes has been 

 abandoned on account of the pest. During recent years it has 

 spread to central Texas and there seems to be no reason why it 

 should not spread over the Gulf States. It is a cosmopolitan 

 insect being reported from China, India, Madagascar, Australia 

 and Cuba. It was first noticed in the vicinity of New Orleans 



* Cylas formicarius Oliv. Family Curculionidce. See Farmers' Bulletin 

 1020, U. S. JDept. Agr. 



