. Eastern forest insects. Forest insects. is accumulated. Pupation 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 & S.) [=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 longle
. Eastern forest insects. Forest insects. is accumulated. Pupation 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 & S.) [=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. 138) 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 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 1
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Keywords: ., bookcentury1900, bookcollectionbiodive, booksubjectforestinsects
