INSECT PESTS AND THEIR CONTROL 970 



three weeks later than usual or after most of the first brood eggs have 

 been deposited. 



Dept. Bull. No. 5. 



Tobacco Flea Beetle (Epitrix parvula, Fab.). — A small dark-colored 

 beetle, eating holes in the leaves of tobacco. The 

 beetle is a very active jumper and cannot be readily 

 captured. 



Treatment. — Apply arsenicals by spraying or as 

 dust when the injury is first noticed and again a 

 few days later, if the beetles are still present. 



Bur'. Ent. Cir. 123; Year-Book 1910, pp. 281-296. 



Tobacco Worms, or Horn Worms (Phlegethontius 

 quinquemaculata,Ha,w. ,and P. sexta, Johan.). — These 

 two pests are the most destructive of the tobacco 

 insects. They feed on the leaves and buds. 



Treatment. — Hand picking or the use of arsen- 

 icals will prevent serious injury. 



Bur. Ent. Cir. 123; Bur. Ent. Cir. 173 



Western Corn Root Worm (Diabrotica longicor- 

 nis, Say.). — A yellowish green beetle, the larva of 

 which feeds on the roots of corn. There is only 

 one generation of the insect each year. 



Treatment. — The only successful way of com- 

 bating the pest is to rotate crops from corn to one 

 of the small grains. 



Dept. Bull. No. 8. 



Wheat Joint Worm (Isosoma tritici, Fitch). — 

 Most of the injury from this insect has been found 

 in the wheat-growing regions east of the Missis- 

 sippi River. The adult is a small black insect 

 somewhat resembling a small winged ant. Eggs 

 are laid in the straw of growing wheat after several 

 joints have been formed. The larvae develop in 

 the joints and emerge in the following spring. 



Treatment. — Burn or plow under all stubble in the fall. Burn all 

 outstanding straw in spring. Do not scatter green manure in fields to be 

 planted in wheat in spring if infested straw was used for bedding. Fertilize 

 liberally. Practice rotation of crops. 



Bur. Ent. Cir. 66. 



Wheat Straw Worm {Isosoma grande, Riley). — West of the Mississippi 

 River this insect is often a very serious enemy of wheat. The larva works 

 inside the young shoots early in the spring and the later generation in 

 straw. 



Treatment. — Injury can be largely prevented by a rotation of crops 



> Bur. Ent. Cir. 106. 



Larva of Isosoma 



grande in Wheat 



Straw. 1 



