Bianca MullerThere is little more frustrating than waiting for the apples and pears in your garden to ripen, only to discover that something has been eating them from the inside. Coddling moths are a common fruit tree pest, and while the adult moths are relatively easy to overlook, their larvae can cause considerable damage to developing fruit.
The good news is that a few preventative measures, regular inspections and early intervention can help keep these pests under control. Knowing what to look for is the first step towards protecting your fruit harvest.
What are coddling moths?
Coddling moths (Cydia pomonella) are small, greyish-brown moths best known for the damage their larvae cause to fruit trees, particularly apple and pear trees. They can also affect walnut trees.
While the adult moths do not directly damage the fruit, they lay eggs on leaves and developing fruit. Once these eggs hatch, the young caterpillars make their way into the fruit, where they feed on the flesh and seeds, often tunnelling towards the core.
The larvae are usually white or cream-coloured when young, developing a pinkish appearance as they mature. They have a distinctive dark brown head and can grow to approximately 12–20mm long.
How to spot coddling moth damage
One of the challenges with coddling moths is that the damage often starts before gardeners realise there is a problem. The larvae spend most of their time inside the fruit, making regular inspections particularly important.
Look out for these tell-tale signs:
- Small holes in the fruit: Tiny entry or exit holes on apples and pears are often the first visible indication of an infestation.
- Reddish-brown droppings: Look for crumbly, sawdust-like material around holes in the fruit. Known as frass, this is a mixture of insect waste and fragments of fruit.
- Premature fruit drop: Infested fruit may fall from the tree before it is ready to harvest.
- Internal tunnels: When you cut open an affected apple or pear, you may find tunnels leading towards the core, along with damaged flesh and seeds.
- Visible larvae: If you find a small, pale caterpillar with a darker head inside your fruit, coddling moth larvae could be responsible.
It is worth checking fruit that touches other fruit particularly carefully, as these areas can provide hiding places for newly hatched larvae.
How to treat coddling moths
Once you have identified coddling moth activity, it is important to act quickly. The larvae become much harder to control once they have burrowed into the fruit, so the focus should be on preventing newly hatched caterpillars from entering.
Here are a few ways to manage an infestation in your garden.
1. Remove affected fruit
Start by removing any visibly damaged fruit from the tree. Pick up fallen apples and pears regularly, too, as these can harbour mature larvae that may eventually return to the tree or find somewhere to pupate.
Dispose of infested fruit rather than leaving it in the garden or adding it to a home compost heap where the larvae could survive.
2. Use pheromone traps
Pheromone traps are a useful way to monitor adult coddling moth activity. They contain a scent that mimics the female moth’s natural mating signal, attracting male moths into a sticky trap.
Hang the traps in the tree canopy and inspect them regularly. While they can help indicate when moths are active, they should not be relied on as the only control method, particularly if you have a larger infestation.
3. Consider biological treatments
There are biological pest control options available for managing coddling moth larvae, including products containing coddling moth granulosis virus. These target the larvae and can help reduce populations when applied at the correct stage of their life cycle.
Timing is particularly important, as treatments are generally most effective when eggs are hatching and before the larvae enter the fruit.
If the infestation is persistent, speak to a reputable garden centre or agricultural specialist about suitable treatments available in South Africa. Always check that a product is registered for the intended use, follow its label instructions and take care to protect pollinators and other beneficial insects.
4. Inspect your trees regularly
Make a habit of checking your fruit trees every week or two during fruit development. Look for small entry holes, unusual marks and damaged fruit, removing anything suspicious as soon as possible.
Early detection can make a significant difference, particularly if you have dealt with coddling moths in previous seasons.
How to prevent coddling moths in your garden
Preventing coddling moths from establishing themselves in your fruit trees is considerably easier than trying to manage a severe infestation later in the season.
A few simple gardening habits can help reduce the risk:
Keep the area beneath your trees clean
Remove fallen fruit as soon as possible, rather than allowing it to rot beneath the tree. Clear away garden debris and keep the area around the trunk tidy, as mature larvae can use sheltered spots to pupate.
Protect developing fruit with bags
One of the most effective non-chemical prevention methods is to cover individual fruit while it is still young. Special fruit protection bags or suitable paper bags can create a physical barrier that prevents moths from laying eggs on the fruit.
For best results, apply the bags once the fruit has reached approximately 1–2.5cm in diameter, usually four to six weeks after flowering. Thin fruit clusters before covering individual apples or pears, and make sure the bags are secured around the stems.
Remember to remove or open them as the fruit approaches harvest, following the requirements of the particular bag you are using.
Check the bark and branches
Coddling moth larvae can survive winter in silken cocoons beneath loose bark and in sheltered areas around trees. Inspect trunks and larger branches for loose bark and crevices that could provide hiding places.
Monitor moth activity
Consider installing pheromone traps early in the fruit-growing season. Monitoring adult moth activity can help you identify when populations are increasing and when closer inspections may be needed.
Work with neighbouring gardeners
If you have fruit trees close to neighbouring gardens, remember that moths can move between properties. Keeping your own trees clean and well maintained helps, but coordinating pest management with neighbours can make control more effective.
When should you be most concerned?
Coddling moth activity is influenced by temperature and local growing conditions, with warmer weather allowing the insects to develop more quickly. Depending on the climate, several generations can occur in a year.
Rather than relying on a fixed calendar, monitor your trees in relation to flowering and fruit development. Begin checking for damage while the fruit is still small and continue throughout the growing season.
If your trees have experienced repeated infestations, it is worth starting preventative measures early rather than waiting for damaged fruit to appear.
A little extra attention during the growing season can help protect your harvest and keep your apple and pear trees healthier for seasons to come.
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