- Codling Moths come out of cocoons on or near fruit trees in Spring when fruit blossom buds begin to open and nights are dry and not cold.
|photo Dept. of Agriculture and Food Western Australia|
- They flutter around in the evening, eat nectar (adult moths don’t eat fruit), and mate. Wind may take them quite a distance away from where they emerged, possibly to a fruit tree in your garden.
- When temperatures reach 15 degrees Codling Moths lay 50 – 60 eggs usually on leaves or fruit of apple, pear, nashi pear, crab apple and quince trees (sporadically also on walnut and stone fruit).
- The eggs are tiny and nearly transparent, and hatch in ten days.
- The small young caterpillars that emerge make their way to the nearest fruit they can find. They burrow into the fruit (often at the top or bottom). They head for the core, and stay there for 3 – 5 weeks, while eating and growing to full size.
- After having lived inside a fruit for 3-5 weeks, fully-grown caterpillars burrow themselves to the surface of the fruit (telltale signs include lots of ‘frass’ - reddish-brown droppings on the surface of the fruit) and move to a suitable spot to form a cocoon (a crack, crevice, loose bark or other tight space in the trunk of the tree, or debris or mulch or soil under the tree, or a nearby tree support).
|A cocoon removed from under bark - photo by R. Knox (Agriculture Western Australia)|
- The cocoon hatches after a few weeks, and a new Codling Moth emerges. Back to the second dot point and the cycle continues, until temperatures drop to under 15 degrees. In warm locations protected from sea breeze this resulted in three generations of Codling Moths in our recent long summers. All three generations visited the same fruit. No wonder there was hardly a fruit left with a Codling Moth hole.
- The last generation of caterpillars pass through winter dormant in their cocoon, and the cycle resumes at the first dot point.
- When you buy fruit trees get fruit trees on dwarf or semi-dwarf root stock
- Keep trees pruned to a size that allows you to inspect all fruits, or espalier trees
- Consider early-maturing varieties to avoid the third generation of Codling Moth, which is often the most devastating.
- Remove pieces of flaking bark, broken branches, leaf debris and other litter from the tree. Squash any over-wintering cocoons you find.
- Remove ladders, old boxes, stakes and other tree props after checking them for cocoons.
- You may not want to remove sturdy tree supports because the tree will continue to benefit from them. Inspect these supports thoroughly.
- Check nearby wooden fences.
- Remove any bands and traps (see below) that were around the tree trunk last season.
- Remove leaf litter and mulch around the base of the tree. Don’t re-use this elsewhere in the garden or on the compost heap, but dispose of it in your rubbish bin or burn it.
|A pheromone trap|
- Look for and remove flaking bark, broken branches, leaf debris and other litter from the tree.
- Collect any fruit you find with small holes, and destroy it. In a long season three generations of Codling Moths will hatch. Leaving a fruit on the tree because you can’t bring yourself to waste it, will enable the moth to generate more off-spring that will affect more fruit. Do not leave affected fruit lying around. Don’t put it in your compost heap.
- Collect and remove all fallen fruit.
- Check mulch to make sure it is well away from the base of trees.
- Change pheromone sachets if their five week period has expired
- Check other types of traps (see below) that you added.
|A cocoon trap|
|A grease band|
- Your fruit will remain undamaged, which is what all this is about.
- Access to fruit is a crucial part of the Codling Moth’s life cycle. Stopping this means stopping the moth’s reproductive cycle in your local environment, provided you bag all fruit.
- It is also totally effective against birds and possums.
- Effective exclusion makes all other moth pest control measures completely unnecessary.
- waxed paper bags with a built-in twist tie
- special nylon stocking bags with a draw string
- Dipel, also known as Bt (for Bacillus thuringiensis), is used against white butterfly caterpillars on brassica, but it is equally successful against caterpillars of the Codling Moth. Spray the whole tree once a week from when fruit is 10mm. in size, or after rain, whichever comes first.
- Eco Oil can be used to smother Codling Moth eggs. Also, adult moths will not want to land on a surface that is coated with oil. Consistent re-spraying may be necessary to control new eggs and to compensate for rain washing the oil off the surface of the leaves. Begin spraying at petal fall.
- Spinetoram sprays, such as Success Ultra, are derived from naturally occurring soil bacteria. Spinetoram has low toxicity for humans, but a higher risk for pets eg. dogs. Spray the whole tree every fortnight from when fruit is 10mm. in size. For sale at any hardware store.
- White oil can be sprayed to smother eggs and prevent them from hatching. Mix one part of white oil with fifty parts of water. Apply this at weekly intervals throughout the season.
- Pyrethrum can be used to control adult moths and to kill tiny caterpillars before they enter fruit. Pyrethrum is harmful to beneficial insects.