24 DEPARTMENT BULLETIN 1267, IT. S. DEPT. OP AGRICULTURE 



The beetles also feed upon the common rush (Juncus effusus). 

 The culms of this plant form a dense tuft and are extremely tough 

 and dry, except at the base, where they are somewhat tender. The 

 beetles attack and cut them off at that point. Owing to the crowded 

 condition of the culms at the base of the plant, it was not possible to 

 detect the beetles at work, but they were found lying motionless in 

 such situations and beside the broken and shredded culms. Tufts of 

 the rush, from which all imperfect culms had been carefully removed, 

 were transplanted to a cage containing the beetles and, when ex- 

 amined several days later, were found to have a considerable number 

 of their culms broken off and shredded in the same manner as those 

 observed in the field. It would appear, however, that the beetles 

 prefer the Paspalum grasses to the rush. 



Bermuda grass (Capriola dactylon) also is probably eaten by the 

 beetles, though very much less readily than Paspalum. This grass 

 occurs practically everywhere throughout the entire coastal section 

 of Virginia and is especially characteristic of the better cultivated 

 areas. It abounds in many situations in which Paspalum is scarce 

 or lacking. Indeed, it would seem that the chief danger of Euetheola 

 rugiceps perpetuating itself in farming districts and other places 

 outside its typical habitat lies in the universal presence of this grass 

 and the apparent ability of the pest to utilize it as food when no 

 other is available. One would imagine that the hard and wiry stolons 

 of Bermuda grass would scarcely prove very attractive; nevertheless 

 the junior writer has repeatedly found them torn and frayed in the 

 manner characteristic of injury by this species. Similar injury has 

 also been caused by planting the stolons in a cage containing the 

 beetles. 



Corn is attacked by the beetles only in the spring and early sum- 

 mer when it is young. Later in the season the stalks become too 

 hard for them to penetrate. The plants may be attacked as soon as 

 they appear above ground, and are not safe from serious injury until 

 they are fully waist high. The beetles are particularly fond of the 

 apical growing point of the stalk, the so-called " heart," which is the 

 most vital and important part of the plant. In the early stages of 

 growth of the corn plant this structure forms a, minute conical bud, 

 situated below the surface of the ground in the center of the stalk. 

 To reach this part the beetle bores into the stalk at any point between 

 the surface of the ground and thapoint of attachment of the roots, 

 making a large, ragged opening (PL I, B). The work of the beetle 

 is indicated above ground by wilting of the inner set of leaves, the 

 outer ones retaining their rigidity for a considerable period after the 

 other leaves have died. 



In a somewhat later stage of growth, after the stalk proper has 

 begun to elongate and has carried the terminal bud well above 

 ground level, the injury done by the beetle boring into the stalk is 

 usually less severe, only a more or less extensive part of the pith at 

 this time being destroyed, the more vital growing part being out of 

 reach of the beetles. At this time the stalk is also considerably 

 thicker than before, and a beetle may finish feeding before it has 

 destroyed enough of the vascular supply of the plant to interfere 

 seriously with its functions. 



The chief danger to larger corn plants is naturally in the weaken- 

 ing of the stalk, which may result in its being blown over or broken 



