Codling moth is a species with caterpillars that bore into the fruits of apple and pear trees during mid to late summer.

Codling moth is a moth in the family Tortricidae, there are around 400 species of moths in this family in Britain. Most cause no noticeable damage to garden plants.

• The caterpillar’s exit hole is often visible in the side of the ripe fruit or at the 'eye' end (opposite the stalk)
• When the fruit is cut open, the tunnel and feeding damage inside the core can be seen, together with the caterpillar’s excrement pellets (frass)
• Damaged fruits tend to ripen and drop early
• The small white, brown-headed, caterpillar can sometimes be found near the core

It is not worthwhile controlling codling moth on quince or walnut as the level of damage in these fruits is rarely significant. 

• Where possible tolerate the loss of some fruit to codling moth, often only a small proportion of fruits are affected
• Encourage predators and other natural enemies in the garden such as birds, wasps and ground beetles
• Use pheromone traps placed in May (details below), so if necessary action can be taken to avoid a damaging population

• Pheromone traps can be used to trap male moths. They use a synthetic version of volatile chemical (sex-pheromone) produced by female moths to lure in males
• Pheromone traps for codling moth are available from garden shops or from some mail order suppliers. These consist of an open-sided box that is hung in the tree in early May. The bottom of the box has a sticky sheet on which the pheromone pellet is placed. Male codling moths are lured into the trap and get stuck
• These traps alone rarely control codling moth but monitor moth activity. They can help to time other inteventions so they are as targeted as possible
• On isolated trees these traps may catch enough males to reduce the females' mating success, resulting in fewer fertile eggs being laid
• By counting the trapped males every week and following the instructions that come with the trap, the best time for other treatments can be determined
• Pheromone traps are designed to prevent birds entering the trap and getting caught on the sticky sheet, adding some bird netting will further reduce the risk of birds entering the traps

• A mixture of pathogenic nematodes (Fruit and Vegetable Protection) is available by mail order from some biological control suppliers, which may provide some control of codling moth. These are microscopic worm-like creatures that enter the bodies of caterpillars and infects them with a fatal bacterial disease
• The nematode should be sprayed on the trunk and branches, and also the soil under the branches, in September-October, after the caterpillars have left the fruit
• This treatment gives no protection in the following year against female codling moths flying in from nearby gardens, and so may not be worthwhile in areas where apples and/or pears are widely grown
• Whilst the nematode biological controls are usually either insect or mollusc specific, they  therefore have the potential to infect non-target animals within those groups. They should therefore be used with care and only when there is a specific problem to treat

Downloads

Biological control suppliers (pdf document)

Adult codling moths emerge in late May-June and lay eggs on or near developing fruits from June to mid-July. The adults are small, up to 22 mm wingspan, with blackish-brown and grey speckled wings with a bronzy patch  near the outer edge.

After hatching, the small white, brown-headed. caterpillar bores into a fruit and feeds in the core region for about four weeks until fully grown.

The insect leaves the fruit to overwinter as non-feeding caterpillars in leaf litter or under loose flakes of bark, pupating the following spring.