Citrus leafminer

Page last updated: Monday, 20 July 2020 - 10:26am

Please note: This content may be out of date and is currently under review.

Damage

  • This insect attacks all citrus varieties.
  • Larvae infest the young flushing foliage, producing a snake-like 'mine' as they feed. This causes the leaves to twist and curl.
  • Larvae can also attack fruit and stems, though this is rarer.
  • Severe infestations can retard growth of young trees. Infestations on older trees (more than five years) can cause unsightly damage, but do not normally cause significant yield losses.
  • In Western Australia, attacks are most severe in late autumn peaking in April or May, depending on temperature.
  • In spring, damage is minor as the leafminer population is smaller. As a result, only a small proportion of the prolific spring flush is attacked.

Life cycle

Citrus leafminer life cycle includes egg, pupa, larva to adult
Citrus leafminer life cycle
  • Adults are about 2mm long, silvery-white in colour with wings fringed with long hairs. They are visible and are active in the morning and night.
  • Females lay eggs singly under the leaf. Females can lay up to 50 eggs. Newly emerged leaflets (10 – 20mm) are the preferred egg laying site.
  • After 2 – 10 days the larvae hatch. There are three larval stages. When they first hatch, larvae are pale-green and difficult to see. As they begin feeding, the larvae excrete their faeces into the mine forming a visible trail.
  • Larvae cannot move from leaf to leaf or from lower to upper leaf surface, but remain on the same leaf throughout their life. One o eight larval mines can be found on a single leaf.
  • When larvae complete their feeding (5 – 6 days in summer), they mine near the edge of the leaf causing the leaf margin to fold over. The larva moults into the fourth instar or prepupa.
  • Pupation occurs in a fold on the edge of the leaf. The pupa remains in the mine until it emerges as an adult. The pupal stage lasts six days.

Author

Sonya Broughton