is accumulated. Pupaticn takes place inside hollowed-out cones 
or conelets or in silken cocoons on uninfested twigs or cone stalks. 
One generation per year has been recorded in North Carolina. 
Farther South there may be as many as three per year. 
Dioryctria abietella (D & 8.) [=abietivorella (Grote) ] attacks 
the cones, shoots, and bark of many different conifers, particu- 
larly in the genus Pinus, and apparently occurs throughout the 
range of these trees in the Northern Hemisphere. The larvae are 
among the most destructive pests of slash and longleaf pine cones 
in the Southern States. Cones infected with the rust Cronartium 
strobilinum are especially attractive (513). In the Lake States 
and southern Canada, red pine cones also are occasionally seri- 
ously damaged. The adult (fig. 188) is dark gray with white, 
zigzag lines bordered by black on the forewings, and has a wing- 
spread of about 20 to 30 mm. Mature larvae are usually reddish- 
purple with a greenish tinge below, and are about 20 mm. long. 
F-519534 ~ 
FIGURE 138.—Adult of 
Dioryctria abietella. 
There appears to be one generation per year in southern Can- 
ada; in Florida there may be five or six. Infestations in rust- 
infected cones are noticeable as early as April in Florida. By mid- 
June attacks on second-year cones are also apparent. 
The spruce coneworm, Doryctria reniculella (Grote), occurs 
throughout most or all of the forested regions of Canada and as | 
far west as the Lake States in northeastern United States. Its 
preferred hosts appear to be white spruce and balsam fir, but 
many other conifers including Sitka, Engelmann, red, black, 
Norway, and Colorado blue spruces, Douglas fir, larch, and jack 
pine are also attacked. The adult is usually silvery-gray and has 
a wing expanse of 22 to 26 mm. The forewings are marked with 
zig-zag white lines and a white discal spot. Mature larvae are 
reddish or amber brown, have hairy warts on each body segment, 
and are about 18 mm. long. 
In Canada, adults emerge from late June to early August and 
deposit their eggs singly or in small groups in such places as 
cracks or fissures in the bark of stems and twigs, in lichens, 
within the axils of shoots, or between the scales on cones. The 
eggs hatch in about 10 days, and the young larvae, without feed- 
ing, spin hibernaculae in which they spend the winter. When they 
become active again in the spring, they usually mine one or two 
needles and then move to and bore into buds, staminate flowers, 
or cones. During certain years, this species takes a heavy toll 
of white spruce seed (495). 
355 
