Species Cimbex americana - Elm sawfly

Tentrède de l'orme (French)

First described in 1817 by William Elford Leach

18-20 mm (adult), 25-50 mm (larva)

The largest North American sawfly with larvae reaching almost two inches. Larvae are a yellowish-white color and possess a black dorsal stripe. While feeding, the larvae usually coil their posterior around a leaf or twig. At rest the larvae roll into a characteristic tight coil. The larvae spin tough, papery cocoons in the litter or just below the surface of the soil. Pink coloration is not common, most larvae are green to yellow in color.

Adult has glabrous thorax with white/yellow spot above, orange antennae.

Much of NA (NF south to NC west to CO & AK)(1)

Woodlands

adults May-June(1)

hosts include elm (Ulmus), maple (Acer), birch (Betula), willow (Salix), and basswood (Tilia); adults girdle bark on twigs

Larvae have chemical defenses, ejecting fluids from glands near spiracles; often coil hind end around twigs; overwinter in cocoons, and pupate in spring

not considered a problem in forest situations, but can defoliate shade and ornamental elm and willow trees ( Forestry images)