Sequoia pitch moth

  • Latin name: Synanthedon sequoiae (Hy. Edw.)
  • French name: Nodulier du séquoia
  • Order: Lepidoptera
  • Family: Sesiidae
Description

Distribution

British Columbia

This moth occurs from the coast to the Rocky Mountains and from central British Columbia southward into California.

Micro-habitat(s)

Bark, Trunk, Branch

Damage, symptoms and biology

The sequoia pitch moth, Synanthedon sequoiae (Hy. Edwards) (Lepidoptera: Sesiidae), may attack any suitable host trees over 2 m in height. The damage caused by this insect is easily located by the large pitch masses found on the main stem and branches. In most situations, this insect causes little permanent damage, but occasionally serious damage to young trees results if the trees are sufficiently weakened at the point of attack to cause later breakage.

The sequoia pitch moth attacks all sizes of trees, from regeneration to mature. Trees growing in open situations such as those in landscape plantings, parks, roadsides, spaced plantations or along the edges of forests are most susceptible to attack. Trees suffering recent wounding of the stem by pruning, mechanical injury (increment borer hole, axe blade, etc.) as well as those damaged by previous pitch moth attack are particularly susceptible.

Permanent damage rarely occurs. Occasionally, small trees are severely weakened by repeated attacks at the same location on a tree, predisposing it to breakage under the stress of high winds or heavy snow.

Attack sites are made conspicuous by the large pitch masses accumulated over the wounds in the second year. Pitch masses caused by first-year larvae are less noticeable. Pitch accumulations are unsightly and may remain evident for several years after attack.

Egg: Oblong and slightly flattened, about 1.5 mm long and 0.7 mm in diameter. The reddish brown surface has a fine reticulate pattern.

Larva: A mature larva is about 25 mm long. The larva has a reddish brown head and an off-white or yellowish abdomen.

Pupa: 15 to 20 mm long; brown with prominent spines extending across the top of each abdominal segment.

Adult: The adult is a clear-wing moth superficially resembling a yellow-jacket wasp. The head and thorax are black with yellow markings; the abdomen is black with yellow bands. The female is about 16 mm long and the male somewhat smaller. The wingspread varies from 18 to 30 mm.

The flight period occurs during June and July. After mating, the female deposits eggs singly in bark crevices or in wounds on the host tree. Eggs may be laid at any height on the trunk or on the branches. The eggs hatch within 2 weeks. The newly emerged larva bores into the inner bark and the outer sapwood where its feeding activity continues for 2 years. Winding mines are produced at the feeding site, causing copious flows of pitch to accumulate at the point of entrance. The mature larva pupates during June in a silk-lined chamber at the end of a tunnel in the pitch mass close to the outer surface. The pupal stage lasts about 30 days. Just before adult emergence, the pupa forces half of its length through the thin shell of pitch. The newly emerged adult mates and then dies within a few days after oviposition has been completed.

Canadian Forest Service Publications

Sequoia pitch moth

Diet and feeding behaviour

  • Phloeophagous : Feeds on phloem.
    • Borer: Bores into and feeds on the woody and non-woody portions of plants.
  • Xylophagous : Feeds on woody tissues (wood).
    • Borer: Bores into and feeds on the woody and non-woody portions of plants.
Information on host(s)

The principal host of the sequoia pitch moth in British Columbia is lodgepole pine. Other host trees include ponderosa pine, various species of ornamental pines having needles in bundles of two or three and rarely spruce.

Main host(s)

Lodgepole pine, ponderosa pine, shore pine, Sitka spruce

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