April, '19] McCOLLOCH: ELEODES OPACA 185 



began in the fall of 1917, and is still in progress. In Kansas, west of 

 the 98th meridan, the infestation has been general and entire fields 

 have been destroyed. Reports of serious injury have also been re- 

 ceived from Oklahoma and northwestern Texas. During the present 

 outbreak the injury has not been confined to wheat, but has included 

 oats and barley and occasionally corn and sorghums. 



In all probability this insect has been responsible for much injury to 

 wheat previous to 1908, but has been confused with the true wire- 

 worms and other insects. Many of the letters in the files of the De- 

 partment of Entomology prior to this time refer to wireworms damag- 

 ing fall sown wheat. From the text of these letters it would seem now 

 that the insect in question was Eleodes opaca. In the field investiga- 

 tions the writer has often found the farmers confusing false wireworm 

 injury with that caused by true wireworms, white grubs, fall army 

 worms, Hessian fly, and winter killing. 



Nature of Injury and Food 



The principal injury by Eleodes opaca is done by the larvae during the 

 fall. At this time they attack the wheat seed immediately after plant- 

 ing and destroy it before germination. During dry years when the 

 grain may lie in the ground several weeks before sprouting, the injury 

 becomes most severe. After the seed germinates the injury becomes 

 less noticeable and often ceases altogether. In some cases, however, 

 considerable damage may occur after the wheat is several inches high. 

 This was especially true in 1911 when the larvae destroyed many fields 

 by cutting the plants off just above the seed. Occasionally some 

 damage occurs in the spring, due to the larvae burrowing through the 

 stalks or even cutting them off. The original food of the larvae was 

 apparently the roots and seeds of native grasses and weeds, but within 

 recent years, due to the breaking out of the native sod, wheat has ap- 

 parently supplemented this food. In the rearing work the best results 

 have been had by feeding the larvae wheat seed and bran. Other foods 

 have been used, but in all cases the larvae either died or made a very 

 slow growth. Aside from wheat it has been possible to rear the worms 

 on sprouting corn, foxtail seeds, and crab grass roots. In one instance 

 larvae were found feeding on the roots of bindweed in the field. During 

 the present outbreak, serious damage has occurred in the spring to 

 oats, barley, sorghums, and corn. In every case these crops were 

 planted early on land where the worms had destroyed the wheat the 

 previous fall. Wheat is subject to the greatest injury because it is 

 planted at the time when the larvae are reaching maturity and are 

 voracious in their feeding. Swenk (1909, p. 334) reports larvae found 

 in ears of corn that had probably fallen on the ground. 



