budbreak. At first, larvae feed within the protective folds of young leaf clusters and 
later roll or fold one or more entire leaves or leaf parts. Pupation takes place in leaf 
rolls in June and adults appear in July. 
Many other species of Archips are also encountered in eastern forests (446). A 
few of these and some of their hosts are as follows: A. infumatanus (Zeller) — 
hickory and pecan, A. negundanus (Dyar)—boxelder, A. rileyanus (Grote)— 
hickory and walnut, A. georgianus (Walker)—oak, A. griseus (Robinson)—oak 
and hickory, A. magnolianus (Fernald)—cucumbertree, and A. purpuranus (Clem- 
ens)—basswood, paper birch, quaking aspen, willow, and black cherry. 
The spruce budworm, Choristoneura fumiferana (Clemens) (fig. 58). occurs in 
North America from Virginia to Labrador and westward to the MacKenzie River 
Valley, Yukon Territory (//50). At one time, it had been considered present 
throughout the ranges of spruce and fir in North America. Forms occurring in 
western Canada and the Western United States are now considered different species 
(448, 997): however, the question of speciation does not appear to be settled (997, 
1165). Balsam fir is the preferred host of the spruce budworm. To a lesser degree, it 
also feeds on white, red, and black spruces, and on larches, pines, and eastern 
hemlock (698). 
Spruce budworm adults are mostly gray, sometimes ochreous gray. The male has 
a wingspread of about 24 mm; the female, about 26 mm. Full-grown larvae are 
about 20 to 23 mm long. The head is usually almost entirely dark brown, the 
prothoracic shield is brownish yellow with some diffusion of brown pigment or is 
entirely dark brown, and the anal shield is brownish yellow. Pupae are light to 
reddish brown except for darker bands and spots. 
Spruce budworm adults are active from late June to early August, depending on 
location, and the females deposit their eggs in elongate masses of 2 to 60 eggs each, 
the eggs overlapping like shingles on a roof. A large proportion of the masses are — 
usually found on needles near the periphery of the crown. The eggs hatch in about 
10 days under normal conditions. After a period of | to 2 days, during which larvae 
are dispersed by wind throughout the tree and stand, the larvae spin hibernacula in 
suitable sites and molt to the second instar. While the majority of hibernacula are 
found on the branches of host trees, some are also found in mined buds, in flower 
scars, under bark scales, or under lichens. Many larvae become dislodged while 
searching for overwintering sites and drop down on silken threads. At this time, 
they may be blown considerable distances by the wind, often into uninfested stands. 
In the spring, after several days of warm weather but before balsam fir buds 
expand, the overwintering larvae emerge and start to feed. The new buds of 
staminate flowers are attacked first if present; otherwise, the larvae bore into old 
needles. After a short period of feeding here, the larvae move to the ends of 
branches and bore into expanding, vegetative buds. Later, they feed on the new 
foliage of developing shoots. When about half grown, they begin tying the tips of 
two or more twigs together with silk, forming a small nest. During this period, old 
needles are avoided until all of the new ones are eaten or cut through. Feeding is 
usually completed during late June or early July. Pupation usually takes place 
within the last-formed nest but may occur at twig axils. Adults appear in about 10 
days and are subject to considerable dispersal by the wind. The female does not fly 
until she has deposited one or two egg masses. Wind dispersal may be the most 
important factor influencing population trends in any given area (503, 582). 
In light or moderate infestations, spruce budworm injury is restricted to the 
partial loss of new foliage, especially in the upper portion of the crown. Damaged 
164 
