40 



FARMERS BULLETIN 860. 



of the leaves. Such conditions are seldom of 

 large area, usually being confined to spots 

 ranging in area from one to several square 

 rods along the high margins or on relatively 

 high and sandy areas in the interior of the 

 bogs. (Fig. 35.) 



DE.StKIPTIOX AXU SkASOXAL HiSTORY. 

 HIBERNATION. 



Hibernation occurs in the grub stage, from 

 1 to 10 inches deep in the bog soil, and is ac- 

 complished safely even on winter-flowed bogs. 

 The grubs lie in their earthen cells until after 

 the flowage is drawn off in the spring, when the more deeply buried 

 ones move closer to the surface and all transform to pupse, soon 

 after which the emergence of the beetles takes place. The holes 

 which the beetles leave in the soil may be seen easily on hard, sandy 

 bottoms where there is little trash. 



Fig. 36. — Cranberry root- 

 worm : Larva, or grub. 

 Much enlarged. 



THE I.ARVA. 



Most of the life of the rootworm, or about 10| months on an 

 average, is spent in the larval stage. Grubs may be found, however, 

 at any season, because each year a few fail to complete their growth 

 and therefore spend two winters in the ground. 



The full-grown larva (fig. 36) is about five-sixteenths of an inch 

 long, whitish, with brown head, and usually lies in a curved position. 



Hatching of the 3^ellow eggs begins in mid- July and the grubs then 

 commence their root feeding, which lasts until early October, when 

 hibernation begins. 



THE PUPA. 



Transformation from grub to pupa takes place in late May and 

 early June, the time depending upon the date of removing the winter 

 flowage; late holding of the flowage acts as a delay of pupation. 

 Pupa" usually are found in the surface inch of soil and the stage 

 lasts about 2 weeks. The pupa (fig. 37) is white and slightly shorter 

 than a full-grown larva. 



THE BEETLE. 



Emergence of the beetles from the soil begins about mid-June and 

 is at its height a few. days later. In a cage placed over a badly 

 injured area of vines an average of 20 beetles emerged to the square 

 foot. During the day they are not found so readily as at night, when 



