Codling moth
Registered against on 3 crops
Codling moth (Cydia pomonella) is one of the most serious insect pests of pome fruit in Australia. The larvae burrow directly into developing fruit to feed on the core and seeds, causing irreparable internal damage that renders the crop unmarketable for both domestic fresh fruit markets and export trade.
Unmanaged populations can destroy a large proportion of an orchard's yield through direct fruit drop and rejection at the packing shed. Entry points created by larvae also allow secondary fungal rots to enter, increasing fruit breakdown in the orchard and during post-harvest cold storage.
Where it matters in Australia
Codling moth is a major pest across all primary Australian pome fruit districts, including the Goulburn Valley in Victoria, Batlow and Orange in New South Wales, the Adelaide Hills in South Australia, the Granite Belt in Queensland, the Huon Valley in Tasmania, and Manjimup in Western Australia. While its primary impact is in apple and pear orchards, registered control options also extend to cherry crops. Inland regions with warmer spring and summer temperatures generally experience more generations per season than cooler southern or high-altitude districts.
Symptoms
Initial damage appears as small entry holes on the fruit surface, typically surrounded by dark reddish-brown frass (insect excrement) pushed out by the feeding larva. Entry holes frequently occur where two fruits touch, where a leaf rests against a fruit, or inside the calyx cavity. Shallow, aborted feeding attempts leave small surface scars known as stings. Active entries show progressive frass accumulation, and internal inspection reveals dark, frass-filled tunnels extending into the core where seeds have been consumed. Affected fruit often colours prematurely and drops from the tree before harvest.
Life cycle
Codling moth overwinters as mature larvae inside silken cocoons hidden under loose bark, in litter on the orchard floor, or within wooden fruit bins and shed structures. As temperatures warm in spring, larvae pupate and adults emerge, typically around late blossom or petal fall. Moths are active mainly at twilight on warm evenings when flight conditions are favourable. Females lay eggs individually on leaves and fruit surfaces. Newly hatched larvae seek out fruit, bite through the skin, and tunnel directly toward the central core to feed on seeds. Once mature, larvae exit the fruit to pupate in bark crevices, giving rise to summer generations. In warmer growing regions, multiple generations can complete development during a single season before shortening autumn daylight triggers winter diapause.
Monitoring
Install delta traps baited with female pheromone lures in the upper third of the tree canopy before early spring emergence. Check and clean traps weekly, recording adult male moth counts in the spray diary to identify flight peaks and establish biofix points. Combine catch data with local temperature records or degree-day phenology models to predict egg hatch timing. Supplement trapping with regular visual crop scouting from spring through summer, examining at least 20 to 30 trees per block. Focus inspection on fruit clusters, touching fruit pairs, and calyx ends for signs of fresh stings or protruding frass, paying close attention to border rows near packing sheds or unmanaged neighbour trees.
Management
Integrated Pest Management (IPM) for codling moth combines mating disruption, cultural hygiene, biological control, and targeted chemical applications. Mating disruption dispensers should be installed across entire blocks prior to spring moth emergence to disorient male moths and disrupt mating. Cultural hygiene involves removing abandoned host trees nearby, clearing fallen fruit, and managing fruit bin storage areas to minimise overwintering carryover. Conserve natural predators and parasitoids by choosing selective insecticides whenever chemical intervention is required. Rotate active ingredients across different mode-of-action groups between generations to manage resistance risk. Always refer to the approved product label for crop-specific registrations, withholding periods, and application requirements.
Crops with registered control options
Common questions
- How does mating disruption fit into a codling moth management program?
- Mating disruption releases synthetic female pheromones throughout the canopy to prevent male moths from finding females. It is most effective in relatively uniform, well-managed blocks with low to moderate background pest pressure. Because it does not kill adult moths or existing larvae, supplementary selective sprays based on trap counts may still be required along orchard borders or during high-pressure periods.
- What is the difference between a 'sting' and an active entry?
- A sting is a superficial skin wound caused when a newly hatched larva bites into the fruit skin but dies or abandons the site before penetrating deep into the flesh. An active entry features a deeper hole with moist, reddish-brown frass extruded around the opening, indicating a live larva actively feeding inside the fruit.
- Why are fruit bins and packing sheds considered codling moth risk areas?
- Overwintering larvae frequently seek shelter in dry, protected crevices inside wooden fruit bins, bin stacks, and packing shed walls. Adult moths emerging from these structures in spring can re-infest adjacent blocks even if mating disruption is active. Storing bins well away from orchard blocks or managing bin stacks helps reduce this risk.
- How do registered control options differ between apples, pears, and cherries?
- Product registrations vary substantially across host crops. While dozens of products cover apples and pears, very few are registered for cherries. Always check the approved product label to confirm that your specific crop is listed before applying any chemical, and follow all label directions.
- How can I prevent codling moth from developing resistance to insecticides?
- To prevent resistance development, rotate insecticides from different mode-of-action groups between distinct moth generations rather than applying the same chemical class repeatedly across a season. Combining chemical controls with non-chemical tactics like mating disruption, good orchard hygiene, and conservation of natural enemies further reduces resistance pressure.
- When should pheromone traps be placed in the orchard block?
- Position pheromone monitoring traps high in the tree canopy in early spring prior to bud burst or pink bud stage. Setting traps early establishes a accurate baseline for the first spring moth flight, which is critical for degree-day calculation and timing subsequent management actions.