THE SO-CALLED TOBACCO WIRE WORM IN VIRGINIA. 11 



The larvae attack the young corn near the surface of the ground and 

 hurrow into the base of the stalks, the outer portion of the stalk being 

 frequently girdled. If the stalks are small when attacked, they are 

 either killed or so stunted or dwarfed that they never fully outgrow 

 the injury, and produce little or no grain. Much of the corn is 

 attacked just after the seed has sprouted. The larvae frequently 

 burrow into the folded leaves as the corn is coming through the 

 ground. As the leaves unfold they show transverse rows of holes. 

 When the stalks reach a height of a foot or more comparatively little 

 damage is done. Several larva? are frequently found about the roots 

 of a single stalk, and as many as 22 have been collected from a single 

 hill of corn. In wet weather injury is not apt to be so severe, as 

 the plants are then more vigorous and the weeds, which furnish suit- 

 able food for the worms, more plentiful. As with tobacco, corn is 

 attacked when the natural food supply of the "worms" is cut off. 



GENERAL FEEDING HABITS. 



The feeding habits of the "wireworm" on plants other than corn 

 and tobacco are, in a general way, the same. There is a tendency to 

 girdle soft-rooted plants, such as plantain and the wild carrot (PL II, 

 fig. h), and the larvae are often found embedded in cavities where they 

 have fed. The buckhorn plantain (Plantago lanceolata) is frequently 

 killed where the infestation is heavy. A marked preference is shown 

 for the natural food plants, and farmers, when the larvae are especially 

 troublesome, frequently take advantage of this fact by cultivating at 

 first only one round to the row, allowing the weeds to grow in the 

 center of the row until the corn or tobacco has become better estab- 

 lished. In a plowed field the larvae, if they have not finished feeding, 

 concentrate about plantain, daisy, and stickweed (Aster spp.) which 

 have not been killed by plowing. 



The larvae do not seem to travel far in search of food, as was 

 ascertained by plowing badly infested land adjoining fields of corn 

 and tobacco. When disturbed they crawl actively in either direc- 

 tion, and they will often spin a slender silken thread by which they 

 may be suspended. They feed most actively at night. 



THE pvpje. 



The larvae pupate in the soil near the plants on which they feed. 

 Before pupation there often seems to be a rather long period during 

 which the larvae remain inactive in their cells. The pupal cells are 

 usually found at a distance of from 1 inch to 6 inches from the base 

 of the food plant and at a depth varying from one-half inch to 4 

 inches. 



* Table V shows the depths at which pupae were found about various 

 food plants in soils varying from hard stiff clays to loose sandy loams. 



