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Leaf Rollers (fruit tree & oblique-banded)

Characteristics:

  • Eggs: Female oblique-banded rollers lay a light green egg mass on the upper surface of leaves that resembles small overlapping scales. Females lay eggs on leaves where they hatch. Female fruit tree rollers lay a white egg mass on the surface of twigs and branches that resembles small overlapping scales.
  • Larvae: Larvae from both species look very much like a cankerworm – light to dark green in colour and very small (1 – 10 millimetres in length). However, the leaf roller has a dark black head and will wiggle backwards away from an object placed in front of it.
  • Pupae: Both species pupate inside rolled leaves and emerge as moths.
  • Adults: Adult oblique-banded rollers emerge in June after larvae overwinter in silk cases. Adult fruit tree rollers emerge in the middle of June to July. Both species are 10 to 20 millimetres in length, and have light to dark brown wings with dark bands.

Identifying infestations:

  • Deformed fruit tree buds, blossoms, leaves and fruit: Fruit tree rollers will cause deformed buds, blossoms and leaves as they feed in these areas. Fruit may have pinpricks where roller has entered the fruit; eventually the damage becomes larger and causes deforming scars.
  • Silk-covered rolled leaves: The larvae of oblique-banded rollers feed inside rolled leaves tied with silk.

IPM Toolkit:

  • Preventive tools:
    • Green ash trees are especially vulnerable to leaf rollers because the tree ‘leafs’ out slowly, so the leaves emerge already damaged.
  • Physical tools: Not applicable
  • Biological tools: Not applicable
  • Least toxic chemical tools:
    • Apply Bacillus thuringensis var. kurstaki (also known as Organic Insect Killer, Bt.k.) according to label directions