ie 
F-488104 
FIGURE 79.—Damage by the 
pine root collar weevil, 
Hylobius radicis, at the 
base of a pine tree. 
the root collar and layers of pitch-infiltrated soil near damaged 
areas are evidences of infestation. A number of silvicultural prac- 
tices have been suggested for reducing populations (780). Finne- 
gan and Stewart discussed methods of direct control (251). 
Hylobius rhizophagus M. B. & W. is a newly-described species 
recently discovered attacking jack pine in the Lake States (532). 
The adult is black and about 14.5 mm. long. Dense patches of 
coarse scales occur on the dorsum and the elytra bear longitudinal 
rows of pits containing fine setae. The larvae feed in roots less 
than one-half inch in diameter, tunneling from the smaller end 
toward the base. Pupation occurs in cells in the roots. Pole-sized 
pines in closed plantations on formerly cultivated land are most 
frequently infested; reproduction in well-established infestations 
and red pines growing in mixture with jack pine are also attacked 
occasionally. 
Hylobius warrent Wood attacks most species of conifers grow- 
ing on moist to wet sites in southern Canada and south to North 
Carolina in eastern United States. The adult is a large, robust, 
reddish-brown to black weevil, from 12 to 15 mm. long. The wing 
covers are thick, tough, and veinless and each bears 10 rows of 
longitudinal punctures. The hindwings are vestigial. Eggs are 
deposited around the root collars of healthy trees, and the larvae 
feed in the inner bark and cambium of roots and root collars for 
1 to 2 years. Infested trees bleed heavily at the ground line and 
severely injured ones may be completely girdled and killed. Up to 
40 percent of the trees in a 40-year-old Scotch pine stand in 
Quebec are reported to have been killed by the species. H. pinicola 
(Couper) occurs throughout the same range as H. warreni and 
apparently breeds in the same species of trees. The adults of the 
two species are similar in appearance, but differ in that the hind- 
wings of this species are fully developed. Warren (741) described 
H. warreni in detail. 
216 
