or late summer, they become full-grown and pupate in chambers 
formed in the wood or pith. Adults appear in 10 to 15 days and 
feed until late fall on both old and mature new growth. Some- 
times, this feeding alone is severe enough to kill entire shoots. 
The white-pine weevil is the most serious insect pest of eastern 
white pine in North America. Its damage results in two types of 
loss: (1) reduction in recoverable volume; (2) lumber degrade 
in the remaining volume. Studies in New Hampshire showed an 
estimated volume loss of 40 percent in the sawlog portion of saw- 
timber trees and 70 percent loss in the portion above sawlog 
limits of merchantability. The average volume loss in pole-size 
trees was 13 percent (744). 
The first evidence of attack in the spring is excessive pitch flow 
from feeding punctures on the preceding year’s terminal shoots 
(468). Later, the new growth appears stunted, and finally, the 
needles wilt (fig. 75 B). Trees up to 3 feet tall may be killed. 
Killed terminals on taller trees are replaced by one or more 
branches of the topmost living whorl assuming vertical growth, 
resulting in crooked or forked stems (fig. 75 C). Trees suffering 
this type of damage for several years become multiple-stemmed, 
cabbage-shaped, and worthless. 
The white-pine weevil has been studied intensively during the 
past several years, and much has been learned about its biology, 
ecology, and control. As a result of these investigations, the fol- 
lowing management practices have been recommended for reduc- 
ing losses to white pine: (1) the planting of white pines with 
hardwoods or under a hardwood cover; (2) the planting of white 
pine on medium soils only where soil matting or hard pan does 
not occur within 3 feet of the surface and where the trees will not 
suffer from competition with hardwoods or jack or red pines; 
(3) the selection and improvement by pruning of the least injured 
pines for a final crop in heavily infested stands; and (4) the 
removal of less desirable trees from white pine stands (467, 705, 
706, 303, 56, 796, 507, 159, 598). Other types of indirect control, 
such as that exerted by insect parasites and predators and birds, 
are helpful in preventing excessive high weevil populations, but 
are incapable of preventing intolerable levels of loss. Harman & 
Kulman (321) published an annotated list of the parasites and 
predators of the species. 
The northern pine weevil, Pissodes approximatus Hopk., a close 
relative of the white-pine weevil, occurs from the Atlantic Coast 
to Manitoba in Canada and southward to Minnesota and North 
Carolina in the United States. Its preferred hosts appear to be 
red and Scotch pines, but it also attacks eastern white, pitch, jack, 
shortleaf, Virginia, Table-mountain and Austrian pines, and red, 
black, and white spruce. The adult is very similar to the adult of 
the white pine weevil but is somewhat larger, being about 5 to 8 
mm. long. The beak is also somewhat larger, and the spots on the 
elytra are uniformly smaller, the posterior ones rarely connected 
24h). 
Winter is spent mostly in the adult stage in the duff and top 
soil beneath infested trees and under scales and crevices of the 
rough outer bark of these trees. The remainder overwinter in the 
larval and pupal stages in the tree. Overwintering adults emerge 
211 
