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Western webspinning sawfly

Western webspinning sawfly -
  • Latin name: Cephalcia californica Middlekauff
  • French name:
  • Order: Hymenoptera
  • Family: Pamphiliidae


British Columbia

This species occurs on the south coast and in the southern interior of British Columbia; it also occurs in mountainous western Alberta and down to California.



Damage, symptoms and biology

Cephalcia californica occasionally causes significant damage on pines planted in urban areas and also to lodgepole pine in seed orchards. Heavily infested trees may be covered with large unsightly webs containing large accumulations of frass.

Mature larva up to 27 mm long. Head, brown with dark markings. Penultimate and earlier instar larvae mottled yellowish brown with dark brown middorsal, midventral and spiracular lines; two prominent black spots above each thoracic leg and on the dorsum of the last abdominal segment. Thoracic legs black.

The final instar larva changes colour becoming green with a faint dark green middorsal stripe. The black spots above the thoracic legs and on the last abdominal segment remain.

This species overwinters as a prepupal larva in earthen cells. Adults emerge in spring or early summer. Larvae construct large frass-filled webs and are active from June to July. Mature larvae drop to the soil from late July to August and construct earthen cells.

Canadian Forest Service Publications

Western webspinning sawfly

Diet and feeding behaviour

  • Phyllophagous : Feeds on the leaves of plants.
    • Webworm: Spins a silk shelter in which to hide or feed.
Information on host(s)

Cephalcia californica is restricted to pines including ponderosa pine, lodgepole pine and western white pine.

Main host(s)

Lodgepole pine, shore pine, western white pine


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