Fir coneworm

Fir coneworm - Larva into its galery of twig
  • Latin name: Dioryctria abietivorella (Grote)
  • French name: Pyrale des cônes du sapin
  • Order: Lepidoptera
  • Family: Pyralidae
  • Synonym(s): Dioryctria abietella Grote
Description

Distribution

Canada

Micro-habitat(s)

Twig, Trunk, Needle, Cone, Branch

Damage, symptoms and biology

Symptoms of an infestation include cones stuck together by frass mixed with webbing, chewed needles and mined terminal shoots.

Larvae prefer cones, but will also feed on the terminal shoots and the bark of the trunk and large limbs. Occasionally, the larvae will even mine the actual branches or trunk of the tree. On young pines, the species’ presence is revealed by a pitch mass near an entry point on the trunk. The fir coneworm does not cause serious damage to the tree, but in severe infestations, it may destroy an entire seed and cone crop. It is particularly damaging in seed orchards.

Towards the end of the larval stage, the caterpillar drops to the ground and weaves a silk cocoon where it overwinters during the last larval instar or as a prepupa, and pupates the following year. In eastern Canada, this species only has one generation per year. Larvae infest the cones beginning in mid-June and remain until fall.

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
 
 
Pupa
 
Adult
 

Other information

Reported in Canada for the first time in 1939, the fir coneworm is similar in many respects to the spruce coneworm. Outbreaks have been limited to occasional local infestations in Ontario and Quebec. Most occurrences have been reported in plantations and seed orchards.

To reduce the larval population on ornamental trees, the cones should be collected and burned while the larvae are still inside (before mid-August).

Canadian Forest Service Publications

Fir coneworm

Diet and feeding behaviour

  • Heteroconophagous : Feeds occasionally on seeds and cones, but usually lives and feeds on stems and needles.
    • Borer: Bores into and feeds on the woody and non-woody portions of plants.
  • Phloeophagous : Feeds on phloem.
    • Borer: Bores into and feeds on the woody and non-woody portions of plants.
  • Phyllophagous : Feeds on the leaves of plants.
    • Webworm: Spins a silk shelter in which to hide or feed.
  • Xylophagous : Feeds on woody tissues (wood).
    • Borer: Bores into and feeds on the woody and non-woody portions of plants.
General information

Specimens are available for purchase from the CFS Insect Production Services.

Information on host(s)

Main host(s)

Balsam fir, black spruce, eastern white pine, jack pine, Norway spruce, red pine, red spruce, scots pine, white spruce

Photos
  • Fir coneworm Larva
  • Fir coneworm Balsam fir cone affected
  • Fir coneworm Pupa
  • Fir coneworm Pinned adult (wingspan: 25 mm)
  • Fir coneworm Larva into its galery of twig
  • Fir coneworm Mature larva
  • Fir coneworm Larva found in cone
  • Fir coneworm Larva in a balsam fir cone
  • Fir coneworm Appearance of an affected cone; frass near the entrance hole of the larva
  • Fir coneworm Damaged cone
  • Fir coneworm Larva on a eastern white pine cone
Date modified: