PEST

NAME
Citrus Leafminer
Phyllocnistis citrella

ORDER
Lepidoptera

FAMILY
Phyllocnistidae

Description of the Pest
This small moth has a 5 mm wingspan and about the size of a mosquito. The wings are silvery narrow and fringed with long hairs. On the end of the forewings is a small black dot. They fly at night.
Larvae are yellowish-green and 4mm long. The larvae feed with chewing mouth parts between the upper and lower surfaces of the leaves, creating silvery tunnels or "mines".

Life Cycle
This insect has a Holometabolouslife cycle, i.e. it has alarvaland a pupal stage.
Eggs are laid singly along the midribs of leaves, from which larvae hatch after 3 days and tunnel into the leaf, creating characteristic irregular silvery lines. They roll the edges of the damaged leaves together to form nests in which they pupate. Under ideal weather conditions, the life cycle takes 2-3 weeks. The adults live for up to three weeks.

Distribution of the Pest
Native to Eastern and Southern Asia. Found in Australia where citrus are grown as well as in Florida and Africa and Pacific Islands.

Period of Activity
Most active from summer to autumn.

Damage Caused
Leaves are disfigured by the tunnelling of the Leafminer; heavy infestations (an average of two or more mines per leaf) can effect the development of growth especially on young plants.

     
Silver wandering mine          Young leaves are distorted

Susceptible Plants
Grapefruit, lemon and lime are most susceptible to damage but this leafminer attacks all varieties, as well as plants belonging to the citrus family Rutaceae.

Control

Cultural Control
Remove and destroy damaged foliage in localised infestations.
Limit feeding citrus in summer, to reduce flushes of new growth on affected plants.

BiologicalControl
Two parasitic wasp have been introduced Ageniaspis citricola, Cirrospilus quadristriatus,
Native parasite Semiolacher petiolatus

Chemical Control
Oils can be used to deter the female from laying eggs on the foliage. Spray once new growth is 10 mm,
Spray until the most of the new leaves are 40 mm in length.

Note
It is your responsibility by law to read & follow the directions on the label of any pesticide
On mature tree spraying new growth is not normally required unless for appearance sake.

Monitoring
Monitor production of significant growth flushes on tree less than 5 years old.
Examine at least 25 advanced shoots (shoots that have emerged earlier than most of the foliage)
Control should be taken if 10% of the advanced flushes are infected
Pheromone traps can be used to monitor adult male citrus leafminers, which can aid in
determining when high populations occur. However, control decisions should be based on sampling for active larvae, primarily on trees less than 5 year old.
Monitoring should begin when 50% of the trees are actively growing

Amendments by B. Sonsie Dip Hort Sc Burnley

Syn. Family name Gracillaridae