PLUM — POTATO 329 



Plum. Canker-worm. — See under Apple, p. 306. 

 CuRCULio {Conoirachelus nenuphar). — Larva, a whitish grub, feed- 

 ing in the fruit. 



Remedies. — Arsenate of lead, 6 pounds to 100 gallons of water; 

 apply as soon as the calyx falls, and repeat two or three times at 

 intervals of about ten days. Jarring the beetles on sheets very 

 early in the morning, beginning when trees are in flower, and con- 

 tinuing from four to six weeks, is probably the most sure proce- 

 dure. There are various styles of sheets or receptacles for catch- 

 ing the insects as they fall from the tree. Clean culture. 

 Flat-headed Borer. — See under Apple. 

 Pear-twig Beetle. — See under Pear, p. 326. 

 Plum-gouger {Coccotorus prunicida). — A small larva, feed- 

 ing upon the kernel of the plum. The beetle bores a round hole 

 in the plum instead of making a crescent mark, like the cur- 

 culio. 

 Remedy. — Catch the beetles over a curculio-catcher. 

 Scale (Lecanium corni). — A large circular scale occurring on 

 plum (and perhaps other) trees in New York. 



Remedy. — Thorough spraying with kerosene emulsion, one part 

 to five of water, in the winter. More dilute emulsion or tobacco 

 extracts in midsummer, when the young insects are on the leaves 

 and young shoots. 

 Slug. — See under Cherry, p. 313. 

 TwiG-PRUNER. — See under Apple, p. 309. 

 Poplar. Cottonwood Leaf-beetle {Lina scripta). — A striped beetle 

 feeding on the leaves and shoots of poplars and willows. 

 Remedy. — Arsenicals. 

 Willow-worm. — See under Willow, p. 336. 

 Poplar Borer {Cryptorhynchus lapathi). — A whitish grub bur- 

 rowing in the wood. 



Treatment. — In nurseries spray thoroughly about the middle 

 of July with arsenate of lead to kill the parent beetles. 

 Potato. Colorado Potato-beetle {Leptinotarsa decemlineata) . — 

 Beetle and larva feed upon the leaves. 



Remedies. — Arsenicals, either dry or in spray, about a third 

 stronger than for fruits. Hand-picking the beetle. 

 Stalk-weevil (Trichobaris trinotata). — A grub boring in the stalk 



