give rise to a group of overwintering larvae. Essentially, however, a single genera- 
tion occurs each year (759). 
The spruce coneworm, D. reniculelloides Mutuura & Munroe, occurs through- 
out the forested regions of Canada and in the Northern and Western United States. 
It feeds primarily upon cones and associated vegetative parts of white spruce and 
various Other spruces and firs but also has been reported from other conifers within 
its range. The moth has dark-gray forewings strongly shaded blackish and crossed 
by distinct white zigzag lines. The hindwings are dusky with an obvious paler, 
diffuse postmedial (outer) crossband. The wingspread is 22 to 27 mm (90/). 
Mature larvae are pale yellow with distinct brown longitudinal stripes and are about 
17 mm long (797). 
In Canada adults are present from late June to August. Eggs are laid in bark 
crevices and similar niches. The first instars diapause over winter. In spring they 
first mine needles then bore buds, staminate flowers, cones, or shoots. Masses of 
webbed frass enclose the food material. During certain years this coneworm takes a 
heavy toll of white spruce cones (S05). 
The blister coneworm, D. clarioralis (Walker), occurs throughout the South and 
northward into coastal Massachusetts. It infests vegetative buds, male bud clusters, 
conelets, and cones of pines including longleaf, slash, loblolly, and shortleaf. 
Adults have blended brown and black forewings marked with wide, nearly black 
transverse bands near the base; wingspread is from 22 to 29 mm (fig. 73). Larvae 
are yellowish brown to brownish orange, often heavily suffused with gray; they are 
about 18 mm long. This coneworm was the most common coneworm found in 
cones of shortleaf and loblolly pines in Arkansas in 1960 (/367), but southwide 
seems to be of lesser importance. 
Winter is spent in the developing larval stage in buds or conelets. Flowers, cones, 
and buds are bored into during the spring, then succeeding generations infest buds, 
shoots, conelets, and occasional cones. A characteristic of damage by this species 
is the presence of a resin-coated silk blister over the entrance hole where ejected 
frass accumulates. Pupation occurs outside the hollowed-out food material on a 
twig or cone stalk in silken cocoons covered with bits of twig scales. Normally 
three generations per year occur in the South. 
The webbing coneworm, D. disclusa Heinrich, occurs in southern Canada and 
throughout the Eastern United States. It infests cones of red, jack, and Scotch pines 
in the Northern States and cones of Virginia, loblolly, shortleaf, and longleaf pines 
F-494452 
Figure 73.—Adult of the blister coneworm, Dioryctria 
clarioralis. 
184 
