Stands may be cut during seed years without danger of excessive 
losses to regeneration. 
The poplar-and-willow borer, Cryptorhynchus lapathi (L.), an 
introduced species first recorded in North America in New York 
City in 1882, now occurs from coast to coast in southern Canada, 
in Washington and Oregon, and south to Virginia in eastern 
United States. Its principal hosts are poplars and willows, but it 
also attacks alder and birch. The adult (fig. 80) is brown to black 
and about 8 to 10 mm. long. The snout is as long as the head and 
thorax combined, and the sides of the thorax, parts of the legs, 
and the posterior half of the elytra are clothed with pale, pinkish 
scales intermixed with large, erect black bristles. Full-grown 
larvae are thick, whitish, and about 12 mm. long; the pupae are 
whitish to yellowish and armed with a pair of strong brown hooks 
at the tip of the abdomen (509). 
Adults appear in late July and August and feed on the inner 
bark of young shoots. Eggs are deposited singly or in groups of 
two to four in slits cut in corky bark, often in lenticels and scar 
tissue. Young larvae feed in the cambial region and outer layers 
of sapwood, tunneling in all directions and pushing out their 
borings through small holes. In late fall, they hollow out small 
chambers in the inner bark in which they spend the winter. Feed- 
ing 1s resumed in the spring, with the larvae usually boring 
around the branch or stem and often causing girdling. When 
ready to pupate, the larvae bore upward and inward and con- 
struct cells in the center of the stem. There is one generation per 
year. 
The first evidence of attack is the occurrence of dead patches or 
eracks in the bark on the trunks of small trees or on the branches 
of larger ones, and the presence of small holes chewed in the 
bark. The wood under these patches eventually becomes honey- 
combed with larval tunnels. Branches or entire small trees may 
be completely girdled or so badly weakened by tunnels that they 
break. All poplars and willows over 1 inch in diameter are subject 
to attack, recently planted trees and nursery stock especially. The 
most serious damage usually occurs near the base. 
The pine gall weevil, Podapion gallicola Riley, occurs through- 
out eastern United States and southeastern Canada. It breeds in 
red, pitch, Virginia and scrub pines. The adult is black and about 
5 mm. long. During June, eggs are laid in niches chewed into the 
bark of 1-year-old twigs. Young larvae feed first on the sides and 
floor of the egg niche and then bore into the cambium. Here they 
separate and tunnel outward from the niche. They continue to 
feed through three seasons. Pupation occurs in funnel-shaped 
cells in the bark during May of the fourth season. Galls are 
formed by hypertrophy of the xylem tissue surrounding each 
larva. They first appear as slight swellings on one side of the 
stem. By the time the adults emerge, these swellings are larger, 
generally ovoid, and taper gradually toward the distal end (fig. 
81). Old galls continue to enlarge, even after the insects leave 
them, some reaching a length of 37 mm. When several galls are 
formed on a small branch, the branch may be killed (776). 
The arborvitae weevil, Phyllobius intrusus Kono, an introduced 
species first recorded on nursery stock in Rhode Island in 1947, is 
218 
