In most localities, eggs are deposited from May to September in cavities in the 
inner bark at the base of the tree, or in the soil nearby (/064). Peak egg laying 
occurs in June (/332). The larvae feed downward in the inner bark of the base of the 
trunk and in the base of large roots below the ground line, widening their galleries 
as they develop. Galleries are also formed in the soil around the base. In the Lake 
States, the winter is spent in the larval stage. In southern Ontario, it 1s spent in the 
larval and adult stages and occasionally in the pupal stage (4/7). Pupation occurs 
from June to September in cells constructed in the soil. Adults appear from August 
to October but do very little egg laying before entering the soil or bark crevices to 
spend the winter. When they emerge in the spring, they feed during the day on the 
bark of duff-covered branches, mate, and lay eggs. During warm evenings, they 
feed on the bark of the upper branches and fly to other trees. Most of these adults 
overwinter a second time and then are active for part of the following season 
(1338). 
Heavily infested trees may be severely injured (fig. 149). Small trees, from 2.5 to 
10 cm in diameter, are most severely damaged; smaller ones are seldom attacked. 
The presence of pitch flows at the root collar and layers of pitch-infiltrated soil near 
damaged areas are evidences of infestation. A number of silvicultural practices have 
been suggested for reducing populations (/327). These include avoidance of sus- 
ceptible species such as Scotch and red pines, particularly in mixed plantings; 
shallow planting and maintenance of fully stocked stands. Weevils in plantations 
can also be reduced by pruning the lower whorls of branches and removing the litter 
from around the hole. This treatment was effective for up to 5 years (/33/). In 
high-value plantations, insecticide should be applied to the base of the trees in late 
May and June before egg laying begins (5/6). 
ETA. 
F-488104 
Figure 149.—Damage by the pine root collar weevil, 
Hylobius radicis, at the base of a pine tree. 
325 
