Included in this section are pests that infest arborvitae, cedar, deodar cedar, fir, hemlock, juniper, pine, and spruce in nurseries and in the landscape. Conifers form a major portion of the shrubs grown by commercial nurserymen. With their amazing variety of forms and shades of green and yellow, conifers are among the most important landscape plants. Although conifers generally require little care, they are occasionally damaged or killed by insects and spider mites in the landscape.

KEY TO COMMON AND IMPORTANT CONIFER PESTS

1. Arborvitae leafminer- Arborvitae leaves are tunneled and brown; heavily infested shrubs are unthrifty and defoliate prematurely; tiny (1- to 3-mm), greenish or brownish caterpillars are found in tunnels.

2. Bagworm-Spindle-shaped silk bags covered with pieces of plant foliage hang from twigs; when bagworms are numerous, much of the plant may be defoliated and may die.

3. Balsam twig aphid-Needles of Fraser fir twisted and curled; bark may have a roughened appearance; aphids are bluish gray but are present only very early in the growing season.

4. Balsam woolly adelgid-Gouty and twisted new growth of fir; needles defoliating prematurely; small, cottony fluffs on the bark of trunk and branches with small, bluish-black insects underneath; heavily infested trees declining or dead.

5. Eastern spruce gall adelgid- Pineapple-shaped galls at the base of new twigs; growth distorted at older galls; small, greenish-white aphids in new galls.

6. Introduced pine sawfly-Colonies of grayish caterpillars with rows of black and yellow spots on sides feed on white and Virginia pines. Heavily infested trees may be defoliated.

7. Juniper webworm-Foliage of junipers webbed together by silk strands; heavily infested shrubs with much dead foliage incorporated in the webbing and dead foliage below the shrub; slender, whitish worms with brown stripes in webbing.

8. Nantucket pine tip moth-Dead buds and shoots are hollowed out; small worms or pupae are inside. Small (up to 6-mm), gray moths may be noticed around dusk.

9. Pine bark adelgid-Small (up to 3-mm), dark insects with conspicuous white, waxy filaments feeding on back. Most noticeable in late winter and spring.

10. Pine needle scale-Needles of pine (sometimes balsam fir, Cedrus, Juniperus) infested with small (1 to 4-mm), white scale insects with light-yellow exuviae on one end.

11. Redheaded pine sawfly-Colonies of yellowish caterpillars with brown spots and orange heads feeding on foliage; small shrubs may be completely defoliated.

12. Spittlebugs--Masses of frothy liquid on twigs of pine. Twig dieback common.

13. Spruce spider mite-Foliage pale yellowish or whitish; foliage may drop prematurely; spider mites may be present in large numbers; foliage may be webbed with fine silk webbing.

14. White pine aphid-Large (up to 6-mm), dark, soft-bodied insects sucking sap from twigs and branches of white pine. Honeydew and sooty molds often present.

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