Greenheaded spruce sawfly

Greenheaded spruce sawfly - Lateral view of mature larva, on Engelmann spruce
  • Latin name: Pikonema dimmockii Cresson
  • French name: Tenthrède à tête verte de l'épinette
  • Order: Hymenoptera
  • Family: Tenthredinidae
Description

Distribution

Canada

Micro-habitat(s)

Needle

Damage, symptoms and biology

The greenheaded spruce sawfly is common and is frequently found together with the yellowheaded sawfly but is considerably less damaging.

Mature larva to 20 mm long. Head, green marked with black stripes along the vertex and sides. Body, green with prominent white addorsal and spiracular stripes.

This species overwinters as a prepupal larva in a cocoon buried in the duff or subsoil. Adults emerge in May and lay their eggs on the new flush. Larvae initially feed on the current year's needles then move onto the old needles. Larvae are active from mid-June to July when they drop to the ground and spin overwintering cocoons.

Life cycle (East of the Rockies)

Life cycle (East of the Rockies)
Stage/Month J F M A M J J A S O N D
Egg
 
Larva
 
Cocoon
 
 
Adult
 

Canadian Forest Service Publications

Greenheaded spruce sawfly

Diet and feeding behaviour

  • Phyllophagous : Feeds on the leaves of plants.
    • Free-living defoliator: Feeds on and moves about freely on foliage.
Information on host(s)

Main host(s)

Black spruce, Engelmann spruce, Sitka spruce, white spruce

Photos
  • Greenheaded spruce sawfly Lateral view of mature larva, on Engelmann spruce
  • Greenheaded spruce sawfly Lateral view of mature larva, on Engelmann spruce
  • Greenheaded spruce sawfly Cocoon
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