Forest Pests: Insects, Diseases & Other Damage Agents

Ash Sphinx - Manduca jasminearum (Guerin)

Great Ash Sphinx - Sphinx cheris (Hubner)

Waved Sphinx - Ceratomia undulosa (Walker)

Solomon, J.D.; Leininger, T.D.; Wilson, A.D.; Anderson, R.L.; Thompson, L.C.; McCracken, F.I. 1993. Ash pests: A guide to major insects, diseases, air pollution injury and chemical injury. Gen. Tech. Rep. SO-96. New Orleans, LA: U.S. Department of Agriculture, Forest Service, Southern Forest Experiment Station. 45 p.

Importance. – Sphinx larvae are seldom serious pests, but they are readily noticed because they are large and ornate caterpillars. All three species occur in Eastern United States. The great ash sphinx ranges from coast to coast and has been known to concentrate locally on clumps of saplings, young trees, and sprouts. Identifying the Insects. - Sphinx larvae (hornworms) become quite large, reaching 75 mm in length. They have a distinctive horn-shaped spine on their distal end. Color markings are mostly pale green, usually with diagonal yellow or white markings. Adults are large moths with stout, spindle-shaped bodies; wings are narrow and brown or gray with dark and light bands. They are very strong fliers and are commonly known as hawk moths or hummingbird moths.

Larva(e); late season leaf feeder, bright patches on sides on caterpillar become "subdued" to lost in later instars Lance S. Risley, William Paterson University

Identifying the Injury - Larvae typically consume the entire blade of tender leaves; mid-ribs and major veins may be left on older leaves. Feeding begins and is most noticeable on the young leaves of terminals and branch ends and progresses toward the older foliage.

Biology. - Adults emerge during May and June and lay eggs on the foliage. Larvae may be found feeding from June to September. Mature larvae burrow into the soil to pupate. There are two generations per year in the South and only one in the North. Overwintering occurs in the pupal stage in the soil.

Control. - Natural enemies usually keep hornworm populations in check. Insecticides are rarely needed to protect seedlings and small trees.

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