INSECTS ATTACKING CORN. 



17 



-WESTERN CORN-BOOT WORM. 

 (Diabrotica longicornis Say; Order, Coleoptera.) 



Diagnosis. Stalks of corn wilt; fall over easily, a strong wind 

 blowing down many. In the roots and in the soil about the roots 

 are to be found small (i to inch long) white six-legged grubs. 



Description and Life-history. The adult is a small beetle 

 about one-fourth inch long, plain greenish-brown to grass green, 

 without spots or stripes, belonging to the leaf-eating family Chrys- 

 omelidse. The eggs are laid in the ground in the fall near the 



Fia. 8. WESTERN CORN-ROOT WORM; a, adult; 6, pupa; c, larva; d, larva in corn root. 



roots of corn. The larvae or "worms" are hatched in May and 

 June, after the ground has been plowed and planted to corn. It 

 is in this worm stage that the injury is done. The worm is from 

 one-fourth to one-half inch long, six-legged, soft, and white, with 

 a small brown head. The worms burrow into the roots of corn, 

 eating their way upward. As many as 15 or 20 may attack a 

 single hill. The corn is stunted in growth, and because of the 

 loss of its roots topples over easily. Many stalks will not be two 

 feet high ; others of the usual height will form no ears ; and some 

 will hardly tassel. 



Remedies. So far as at present known, the insect has no other 

 food-plant than corn, and this suggests at once an effective rem- 

 edy, namely, the rotation of crops and consequent starving of the 

 insect. The eggs being laid in the fall in the corn field, it is evi- 

 dent that, if some other crop than corn be planted on the ground 

 the next spring, the larvre hatching in May and June will be 

 starved to death. 

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