Spruce coneworm

Spruce coneworm -
  • Latin name: Dioryctria reniculelloides Mutuura and Munroe
  • French name: Pyrale des cônes de l'épinette
  • Order: Lepidoptera
  • Family: Pyralidae
  • Synonym(s): Dioryctria reniculella (Mutuura & Munroe)
Description

Distribution

Canada

Micro-habitat(s)

Needle, Male flower, Cone, Bud

Damage, symptoms and biology

Telltale signs of the insect on cones include holes and frass held together by webbing. Reddened needles and frass mixed with webbing between the needles near the buds are also signs of activity.

The larvae mainly feed on cones, although they will turn to foliage when cones are scarce. In spring, the young larvae will mine one or two old needles before moving on to the buds or cones.

The insect also occasionally feeds on pollen from the male flowers, particularly on white spruce. This coneworm may also feed on phyllophagous larvae (such as the spruce budworm) when the latter are competing with it for food, particularly if foliage is scarce.

Cones are sometimes completely destroyed. Severe defoliation results in loss of growth, weakening of the tree and increased susceptibility to attacks by other insects.

The spruce coneworm has one generation per year. Shortly after emerging, the adults lay their eggs here and there in the crown of the tree. When the eggs hatch, the larvae bore into the cones, where they undergo part of their development before entering diapause for the winter. When laying occurs late in the season, the young larvae may overwinter in a silk shelter and bore into the cone the following spring.

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

The spruce coneworm is a native insect often associated with the spruce budworm. It was reported in Canada for the first time in 1937 and almost every year since. Populations usually increase during years of good cone crops.

To reduce the larval population on ornamental trees, the cones should be collected and burned while the larvae are still inside (i.e., in fall or winter).

Canadian Forest Service Publications

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

Main host(s)

Balsam fir, black spruce, red spruce, white spruce

Photos
  • Spruce coneworm Pinned adult (wingspan: 25 mm)
  • Spruce coneworm Young larva in a spruce shoot
  • Spruce coneworm White spruce cones and shoots attacked
  • Spruce coneworm Larva feefing on young cone
  • Spruce coneworm Mature larva on a spruce twig (length: 19 mm)
  • Spruce coneworm
  • Spruce coneworm
  • Spruce coneworm
  • Spruce coneworm White spruce trees defoliated partly by the spruce budworm and partly by spruce coneworm
  • Spruce coneworm Larva into the cone
  • Spruce coneworm Pupa (length: 10 mm)
Date modified: