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Pine Webworm

Characteristics:

  • Eggs: Females lay eggs on needles.
  • Larvae: After hatching, pale green larvae mine the needles. Older larvae live in silk tubes hidden inside a mass built of silk and frass. Mature larvae have brown bodies and yellowish brown heads and can grow up to 18 millimetres long.
  • Pupae: After maturing, larvae pupate in cells formed in the soil.
  • Adults: Adult moths emerge during the summer and are black and grey in colour. Their wingspan is about 25 millimetres.

Identifying infestations:

  • Silken masses of needles and frass: As larvae eat, they build a large mass of frass and silk among the needles of the tree branch.

IPM Toolkit:

  • Preventive tools:
    • Follow a regular watering, fertilizing, and pruning schedule to keep your trees as healthy as possible to resist attack.
  • Physical tools:
    • Remove masses from infested branches.
  • Biological tools: Not applicable
  • Least toxic chemical tools: Not applicable