THE GIANT ROOT-BORER 



267 



THE GIANT ROOT-BORER (Fig. 39) 

 Prionus laticollis (^Dru.). Order Coleoptera: Family Cerambycides 



Riley, Mo. Rep. 1: 124. -2: 87. 

 Saunders, Ins. Inj. Frts. 227. 

 Thomas, 111. Ent. Rep. 6: 147. 

 Smith, Spec. Bull. N., N. J. Exp. Sta. 



The following statements concerning this species are quoted 

 from Professor John B. Smith's bulletin on blackberry insects: 

 "Besides the crown-borer, the black- 

 berry also harbors in its roots an 

 enormous beetle larva between two 

 and three inches in length, white in 

 color, with strongly marked constric- 

 tions at the segments, a distinct en- 

 largement anteriorly, and a small, 

 smooth, brown head, with stout, dark- 

 brown jaws. The parent of this larva 

 is a long-horned beetle, and most 

 probably Prionus laticollis, Dru. Dr. 

 Eiley found this larva injuring roots 

 of grape and apple in Missouri more 

 than twenty years ago, and it has 

 been found also in other trees. So 

 far as I am aware, it has not been 



heretofore recorded as a blackberry pest. Dr. Eiley, from obser- 

 vations made by him, concluded that the larva required three 

 years to come to maturity, and with this conclusion my own ob- 

 servations agree. 



" The pupa is formed in June or early in July, and the beetle 

 makes its appearance at about the middle of the latter month. It 

 is rarely seen, even where not uncommon, and flies principally at 

 night. Fortunately this borer is comparatively scarce ; but where 

 it does occur, signs of its work are readily observable. It lives in 

 the large, woody portion of the main root, in which it bores huge 

 channels, and the sudden dying off of several canes in a hill is a 



Fig. 39. Root-borer. Prionus 

 laticollis. 



