Everyone knows the old joke 'What is worse than finding a worm in your apple?' Answer 'Half a worm' which refers
to the larva of the Codling moth, which originated in Europe but is now found in most countries that grow
apples. It also attacks pears, quinces, and occasionally walnuts and stone fruits.
Suggested Organic Strategies:
- Inspect the fruit every 10 days and remove and destroy infested fruit. Do not bury or place the fruit in
compost heaps. It must be burnt or fed to animals, try cooking it in a sealed black plastic bag in the sun.
If possible have poultry or other animals free-ranging under the trees to eat any fallen fruit.
- Remove any pieces of flaking bark, broken branches and litter from the crotch of the tree, to reduce
hiding places for cocoons.
- Remove ladders, old boxes and tree props from the orchard, first checking them for cocoons.
- The most important natural enemy of the codling moth is the Trichogramma wasp, which parasitises the
moth eggs. As an adult this micro-wasp feeds on insect eggs, nectar, pollen and honeydew. It lives several
times longer and destroys many more pests when supplied with nectar. Properly managed cover crops are the
key to maintaining high levels of predatory insects.
- A horticultural glue around the trunk of
the tree will prevent the movement of some of the female moths from the ground into the tree, as they tend to
crawl and flutter up the branches. It should be in place from the first moth sighting until mid-winter. Using
the glue below the corrugated cardboard bands will also help to force the larvae looking for a pupation site
into the cardboard bands, as it will make it more difficult for them to reach the ground.
Organic Strategies for Codling Moth Control
© Frances Michaels
Codling Moth, Cydia pomonella
, is found in all states of Australia except WA. The greyish-brown moth has
a 20 mm wingspan with metallic copper-coloured patch near each wingtip.
Codling moth photos courtesy of Denis Crawford of
In early spring the moths emerge about the time the fruit trees are in full bloom. The adult moths are about 10
mm long with a 20 mm wingspan, the wings are grey with fine brown bands. There is a metallic copper-coloured
patch near each wingtip and the hind wings are fringed. Tiny, pinhead-sized eggs are laid by each female moth
after dusk, usually on leaves, once the temperature is 15°C or higher. The eggs hatch in about 10 days. The tiny
caterpillars may feed for a while on leaves before moving into the fruit. The caterpillar chews its way into the
fruit core, where it feeds for 3-5 weeks. Damaged fruit often drops prematurely. When it leaves the fruit and
moves down the trunk and branches it searches for a suitable place to spin a cocoon. This might be under loose
bark, in a crevice or in the ground. As the weather begins to cool down the last larvae do not pupate immediately
but remain in their cocoons for some months. There are usually 2-3 generations a year in Australia.
Physical and Cultural Controls
- The most important natural enemy of the codling moth is the Trichogramma micro wasp, which
parasitises the moth eggs, by laying its egg inside the moth egg. The wasp larva then feeds on the contents of
the moth egg. One female wasp is able to parasitise over 50 moth eggs. Trichogramma wasps are commercially
produced in Australia. The adult micro-wasp feeds on insect eggs, nectar, and pollen, a good food supply means
it lives longer. Growing suitable plants under the fruit trees as a pollen and nectar source helps to maintain
a population of these beneficial insects. Suitable plants include
Queen Anne's lace,
- Other natural enemies of codling moth include tachinid flies, ichneumon wasps, braconid wasps, chalcid
wasps, carabid beetles, earwigs and ants. Spiders eat codling moth eggs, moths and larvae.
- Night flying birds, tree frogs and small insectivorous bats will also reduce moth numbers.
- Design your orchard area to be a poultry forage system, the chooks will turn damaged fruit into eggs and
help to control a wide range of pests including codling moth. Do not introduce poultry into a young orchard,
as the poultry will scratch at the mulch, exposing the roots. Where it is undesirable to allow chooks free
range, small demountable fences can be used under specific trees.
Least Toxic Chemical Controls
- The apple season is a peak time to work on your organic strategies for codling moth. Inspect the trees
every 10 days, collect any fruit you find with small holes and destroy it by immersing it in water for
several days. Alternatively place it in a sealed, black plastic bag in the sun, and then try feeding it to
- Remove loose bark and leaf debris from the crotch of the tree, to reduce hiding places for cocoons.
Corrugated cardboard bands can be placed around trunks and limbs to trap caterpillars looking for a place
to pupate. Inspect every 3 weeks and destroy any cocooned caterpillars. The most important trapping time
is winter and spring but for effective control inspect the bands all year round.
- Open-mouthed jars can be filled with a variety of baits to attract codling moth. Try port diluted with
water (1 part port to 9 parts water), fermenting apple juice, molasses or oil of cloves. Add a film of
vegetable oil to the top to stop moths from escaping and prevent mosquitoes breeding. Hang them in trees in
the warmest part of the orchard. Studies have shown codling moth prefer a bait 4-5 days old. Replace the
baits every 2 weeks.
- Light traps, to attract the moths, can be made by suspending a light globe above a pan of water topped
with a thin film of kerosene. Research has shown that using overhead irrigation from 7 to 11pm every night
for 2 months during the period of intense moth activity reduced fruit injury by 90%. This was related to a
climatic study that found rainfall increased larval mortality and decreased egg laying
- A good choice for the home gardener with only a few apple trees is to bag the fruit. Commercial
exclusion bags are available in either
waxed paper with a built-in twist tie or cloth with a drawstring. Bags should be placed over the fruit while
it is very small, first thin the fruit to one piece. It is a good idea to spray before bagging to kill any
small caterpillars already present. Bags should be removed 4 days before harvesting to allow the fruit to
develop a stronger red colour. A big advantage to exclusion is it usually helps deal with bird and possum
problems as well.
- A horticultural glue such as
Trappit Barrier Glue or
Tanglefoot Glue around the trunk
of the tree will prevent the movement of some of the female moths from the ground into the tree, as they tend
to crawl and flutter up the branches. It should be in place from the first moth sighting until mid-winter.
Using the glue below the corrugated cardboard bands will also help to force the larvae looking for a pupation
site into the cardboard bands, as it will make it more difficult for them to reach the ground.
Codling Moth Trap
- Least-toxic sprays such as
Beat-A-Bug Insect Spray can be
used to control the adult moths, once traps have shown that they are active and to kill tiny caterpillars
before they enter the fruit. Spray in bark crevices and under the leaves where the moths will be hiding. There
may be some damage to populations of beneficial insects with the use of pyrethrum sprays. A
Eco-Oil spray can be used to smother
the moth eggs, it should be applied 4 to 5 times beginning at petal fall and then at 10 day intervals.
Dipel contains Bacillus thuringiensis,
or Bt for short; it is an organic bacterial control for caterpillars. To have any effect on codling moth
caterpillars it must be timed carefully; once the caterpillars are safe inside the fruit, it will have no impact.
Eco-Oil with Bt may improve the
- A pheromone is a non-toxic species-specific scent produced by the female insect to attract the male.
Pheromones are a particularly useful control for codling moth as they do not travel very far, usually under 60
metres, and find each other entirely by scent. Synthetic pheromones are used in two different ways:
1. Codling Moth Traps
are new generation codling moth traps that attract both male
moths. They are used
to monitor the mating activity of codling moth and also will significantly help in control. They allow you
to be aware of when codling moths become active and correctly time your control program. Each trap is
usually sufficient for 6 - 8 trees and lasts for 4 - 6 weeks.
Pheromones are also used for mating disruption. By using Isomate twist ties the orchard area is
saturated with pheromones making it extremely difficult for codling moths to find each other in order
to mate. This technique is only suitable for larger blocks of at least 1 hectare; it is unlikely to work
well in a small area.