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Codling moth – additional information

Life cycle

Codling moth has one complete and one partial generation per year in southern Britain, though two generations occur in hot summers.

Pest status

Key pest of apple, less frequently pear though attacks on pear can be very damaging. Attacks fruit directly, so economically important at low population densities.

Other hosts

Walnuts,  Malus sp, quince.

Varietal susceptibility

Host plant resistance is not known to occur in apple cultivars though some Malus sp. with high malic acid content may be resistant.


Widespread and common. World-wide distribution wherever apples are grown except possibly Japan and parts of S.America.


Newly hatched larva (one per fruit) burrow through skin into the flesh and through to the core.

Other pests with which codling moth may be confused

Fruitlet mining tortrix
Larval attacks by the fruitlet mining tortrix occur shortly after blossom.

Blastobasis decolorella
Caterpillars sometimes burrow into fruits from July-September, but damage is usually associated with extensive surface damage.


Adult (resting)
Length 8-11 mm, ash grey with characteristic coppery blotch at wing tip.

1.3 x 1.0 mm, flat, oval and translucent. Found on foliage or fruits, mainly the latter when fruits are more mature.

Typical tortrix form with 5 pairs of prolegs, none on the first two abdominal segments. Up to 20 mm long, pale pinkish white (younger instars whitish). Head and pro-thoracic plate brown. Usually found inside fruit.

Inside thin cocoon. 8-10 mm long, brown. Often found in bark and other crevices.

Other pests with which codling moth may be confused

Apple sawfly
Sawfly larvae are also found in fruit but only up to mid-June. Sawfly larvae taper to tip of abdomen and have 7 or more pairs of pro-legs, though the first abdominal segment is without prolegs.

Fruitlet mining tortrix
Larval attacks by the fruitlet mining tortrix occur shortly after blossom.

Blastobasis decolorella
Caterpillars sometimes burrow into fruits from July-September, but damage is usually associated with extensive surface damage. Blastobasis caterpillars are dark purple-brown in colour.


Pheromone traps
The flight activity of male moths should be monitored using sex pheromone traps. The delta trap design is used widely.

Egg counts
AHDB Horticulture funded research (Project TF 189) showed that pheromone trap catches don’t give a good indication of when the pest is actually laying eggs in apple orchards. Instead, regular egg counting on fruitlets is probably the only fully reliable and accurate way of determining whether and when an orchard needs spraying, but it’s time consuming and unlikely to be done by growers or their consultants.

An alternative way of predicting when egg laying has occurred is to use the RIMpro-Cydia forecasting model in conjunction with sex pheromone monitoring traps (see below).

Fruit damage
Inspecting fruits for damage either whilst developing on the tree or at harvest or grading, may indicate if populations are high and damage is likely from the next generation.

Trunk banding
Applying trunk bands may be used for monitoring.

Forecasting egg laying using the RIMpro-Cydia model

AHDB Horticulture  funded Project TF 204 assessed the effectiveness of the computer based life-stage simulation model RIMpro-Cydia at forecasting egg laying.

Biological control

Codling moth granulovirus
Now that the codling moth granulovirus  is available and approved for use in the UK, it should be used wherever possible, bearing in mind the following limitations:

Key aspects of the virus are:

Sprays of Bacillus thuringiensis (Bt) at the egg-hatch period may give a limited degree of control of codling moth.  However, the newly hatched larvae only feed for a short time before boring into the fruit and do not usually ingest an adequate dose.

A spray of the entomopathogenic nematode Steinernema carpocapse applied to the trunk and main branches in September or early October can give over 80% control of cocooning larvae.

Parasitic wasps
Egg parasites (Trichogramma sp.) are available from biological suppliers and can be introduced but efficacy is poor even if huge numbers are introduced making the method uneconomic.

Chemical control

Although codling moth resistance to insecticides  is widespread in other countries, it has probably not yet developed in the UK.  Chemical control therefore remains the principal means of control in the UK because it is both cheap and effective.

Control with larvicides including pyrethroids, chlorantraniliprole (Coragen), indoxacarb (Steward or Explicit) or spinosad(Tracer)
Several insecticides including deltamethrin, chlorantraniliprole (Coragen), indoxacarb (Steward or Explicit) and spinosad (Tracer) are approved for control of codling moth or other caterpillars on apple in the UK and act by killing larvae.

Control with the insect growth regulator pyriproxyfen (Harpun)
Pyriproxyfen (Harpun) is an insect growth regulator (IGR) that mimics juvenile hormone. Juvenile hormone is a necessary chemical produced during an insect’s development, but becomes toxic when present during metamorphosis.

Insecticide resistance

Codling moth populations are widely resistant to conventional and insect growth regulator insecticides in southern and central Europe. The resistance has forced growers in those regions to adopt alternative control strategies, mainly using pheromone mating disruption and/or codling moth granulovirus. Resistance has not been shown to occur in the UK.

Avoiding the development of insecticide resistance

Although codling moth has probably not yet developed resistance to insecticides in the UK, resistance is widespread in other countries, especially where the moth has multiple generations.

Sex pheromone control

There are three basic methods by which a pest’s sex pheromone can be exploited for control:

The RAK 3+4 mating disruption system

RAK 3+4 is a combined pheromone control system which reduces fruit damage from codling moth (RAK 3) and summer fruit tortrix (RAK 4). Both pheromones disrupt mating behaviour and therefore prevent populations from developing. The pheromones are released from sealed chambers by volatilisation, preventing male and female moths from locating each other and reproducing.

Timing of application and dose rate

Positioning the dispensers

Pheromone attract and kill:
The sex pheromone is incorporated into a material together with an insecticide (usually a synthetic pyrethroid).

Other non-chemical control methods

Sterile insect release
In Canada, codling moths are mass-reared, sterilised and released in an area-wide codling moth control programme.

Cultural control

Many cultural control approaches require high labour inputs and are only likely to be appropriate where other effective control measures are not available.

Old trees

Spatial isolation


Trunk banding

Natural enemies

Codling moth has many natural enemies but these are not sufficiently effective to regulate populations below damaging levels.

Insectivorous birds
Tits, especially, pick larvae and pupae in cocoons from bark crevices, but do not forage specifically for the pest unless population densities are very high and for this reason are of only limited value.

Egg parasites
The egg parasite Trichogramma can be introduced (4 releases of 2.5 m per ha have been shown to reduce damage by 50-80%) but such introductions are not cost effective. Ascogaster quadridentatus is a common, naturally-occurring parasite which lays a single egg in the codling moth egg but develops within the host larva.

Larval/pupal parasites
Many species of parasitic wasp attack codling moth larvae and/or pupae.

Predatory insects
Earwigs and predatory mirid and anthocorid bugs are known to feed on Codling moth eggs and young larvae.

Entomopathogenic fungi
Many species of entomopathogenic fungi, notably Beauveria bassiana, cause significant mortality in overwintered larvae and pupae.

Entomopathogenic nematodes
Neoaplectana carpocapsae are significant natural enemies of overwintering larvae/pupae on tree trunks, especially close to the soil surface.

Virus diseases
Codling moth granulovirus is usually associated with biocontrol applications though the virus can overwinter from one year to the next at a low level.


Further reading

Van der Geest, L. P. S. & Evenhuis, H. H. (Eds). 1991. Tortricid Pests, Their Biology, Natural Enemies and Control. World Crop Pests, Vol. 5. Elsevier, Amsterdam.

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