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Guava moth

Guava moth, from Australia, now attacks fruit in the north of New Zealand. The moth lays eggs on fruit; the caterpillar bores in through a tiny hole and feeds inside, and fruit often drops early.

Pests
A cut feijoa with brown, tunnelled flesh
A cut feijoa with brown, tunnelled flesh

What it looks like

The outside barely shows it.

  • A pin-sized hole in the skin.
    Tiny entry hole A pin-sized hole in the skin.
  • Cut fruit is brown and rotten inside.
    Brown flesh Cut fruit is brown and rotten inside.
  • Dark droppings inside the fruit.
    Frass Dark droppings inside the fruit.
  • Unripe fruit falls from the tree.
    Early drop Unripe fruit falls from the tree.

How to confirm it

Cut some fruit.

  1. Look inside

    Caterpillars and droppings confirm it.

  2. Check fallen fruit

    Early drop with damage inside.

  3. Pheromone traps

    Traps catch males and show when moths are flying.

What to do

Break the cycle through hygiene.

  1. Collect fallen fruit

    Pick up dropped fruit daily and freeze or solarise it before binning.

  2. Bag fruit

    Cover young fruit with fine mesh bags.

  3. Trap males

    Pheromone traps reduce mating in small plantings.

  4. Share the job

    Area-wide control with neighbours works best.

Prevent it next time

  • Keep the ground under trees clear of fallen fruit.
  • Prune trees to a size you can net or bag.
  • Encourage birds and parasitoids.

What not to do

Do not compost infested fruit; larvae complete their life cycle in the heap.

Sources

  1. Coscinoptycha improbana, Wikipedia
  2. Guava moth, Kings Plant Doctor