308 ECONOMIC ENTOMOLOGY 



cucurbits when set out or appear above ground and later deposit eggs in 

 the soil or upon the plants. Beetles of the second brood appear in July. 



Control. — Spray the early and late beetles with arsenate of lead as 

 summer beetles do not eat much. Keep vines well covered with 

 Bordeaux; use trap squashes; place cheese-cloth screens over plants; 

 dust plants frequently with lime, ashes, tobacco dust, etc., to which a 

 little turpentine or crude carbolic acid has been added. 



Twelve-spotted Cucumber Beetle {Diahrotica duodecem-punctata 

 OH v.). — This beetle is a pest of cucurbits and vegetable crops in the 

 north and of corn in the south where it is known as the Southern Corn- 

 root Worm, Budworm or Drill Worm. There are two broods in the 

 north and probably more in the south. 



Adult. — One-fourth inch long, bright green marked with twelve 

 black spots; practically omnivorous; hibernates; May- July; October- 

 November (Ky.). 



Eggs. — Dull yellow, oval, 3^^o inch long; laid singly just beneath the 

 surface of the soil; April- June; hatch in 7-10 days. 



Larva. — Slender, thread-like, delicate and soft bodied; yellowish- 

 white; matures in about a month. Injures the roots, crown and 

 growing bud of the young stem. Breeds chiefly in grasses and corn and 

 on weeds. 



Pupa. — Formed in the soil; duration about a week. 



Western Corn-root Worm {D. longicornis Say) is a corn pest in the 

 northern Mississippi valley. The eggs of this species are oval and 

 dirty white; they are laid in the fall just beneath the surface of the soil; 

 winter over and hatch the following spring after the corn begins to 

 grow. The larvae feed on the roots and often kill the plant; they reach 

 maturity by August ist, and pupate. The greenish-yellow adults emerge 

 in the autumn, and may be found feeding upon pollen and silk of the 

 corn plants; also on clover, beans, cucumber, thistle, golden rod, 

 sunflower, etc. 



Colorado Potato Beetle (Leptinotarsa decem-lineata Say). — The most 

 serious insect pest of potatoes. A native feeder on wild Solanums in 

 Colorado, migrating eastward, reaching the Atlantic in 1874. Found 

 nearly everywhere the potato is grown in United States and Canada. 



Adult. — An oval, convex, robust ochre-yellow beetle with ten black 

 longitudinal lines on wing covers and about 14 spots on thorax; J^-j^^ 

 inch long; hibernates. 



