Caloptilia azaleella (Azalea leafminer moth)
Species: C. azaleella
Binomial name: Caloptilia azaleella
Synonyms: Gracilaria azaleella, Caloptilia anthracosperma, Gracilaria azaleae, Caloptilia azaleae.
Common name: Azalea Leafminer moth.
Caloptilia azaleella is a small moth (about 4- 5 mm body length) of the Gracillariidae family. It is endemic to Japan, it has been introduced worldwide: the Americas, Europe, eastern Australia and New Zealand. This moth is an adventive species, probably introduced with azalea and rhododendron plants.
The adult is a small, yellow or golden-coloured moth with darker markings on the wings. The wingspan is about 10 millimetres and a body length is about 5mm. Most of its life is spent hidden among the leaves of the host plant.
The moth of Caloptilia azaleella deposits eggs leaf near the midrib on the underside of an azalea or rhododendron leaf. Upon hatching, the young larva enters the leaf directly beneath its eggshell and feeds as a leafminer, creating a blister on the underside of the leaf. The mined area turns brown.
Towards the end of the mining activity silk is deposited in the mine; this causes the mine to contract, folding the leaf over the mine. Then a yellowish larva (4.5 mm long) comes to the upper leaf surface and by means of silk pulls the leaf over its body and then chews holes in the leaf. At this stage the larva is known as a leaftier (a moth larva that lives in a folded leaf held together by silk strands). The larva has a head capsule and chewing mouthparts with opposable mandibles, six thoracic legs and abdominal legs.
On maturity as a 13mm larva it selects an undamaged leaf, rolls up in it and pupates. Pupation is in a membranous, shining cocoon on the underside of a leaf.
The adult moth emerges in about a week, mates and begins the cycle again. Moths fly from early spring and through the summer months and can have 2-3 generations per breeding season.