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Willow Leaf Beetle (imported)

Characteristics:

  • Eggs: Females lay yellow, spindle-shaped eggs on the underside of leaves which hatch in a few days.
  • Larvae: Larvae are blackish and are 5 mm in length. They cause major damage as they eat the tree’s leaves.
  • Pupae: After about a month, larvae pupate and are about 10 mm long.
  • Adults: Adult willow leaf beetles vary in colour from black to a metallic green or blue. They hibernate in the winter under loose bark or in other protected places on the tree trunk. In the spring, adults emerge to feed on new shoots and leaf buds before reproducing.

Identifying infestations:

  • Defoliation: Larvae cause major damage to plants as they feed, leaving behind skeletonised leaves.

IPM Toolkit:

  • Preventive tools:
    • Follow a regular watering, fertilizing, and pruning schedule to keep your trees as healthy as possible to resist attack.
    • Preferred food sources.
    • Rake up and destroy leaf litter in the fall.
  • Physical tools:
    • Remove and destroy larvae-infested branches.
  • Biological tools:
    • Parasitic wasps control willow leaf beetle populations.
  • Least toxic chemical tools: Not applicable