My favourite time of year… FEIJOA season!! YUM!! But low and behold, we have a pest that’s out to get us!! The dreaded Codling Moth (Cydia pomonella)!!!
Codling moth caterpillars are little creatures that eat your fruit (namely pear, apricot, peaches, plums, cherries, chestnuts, walnuts and feijoas) and leave brown exit holes causing considerable damage.
Life cycle of the Codling Moth
In Winter, caterpillars cocoon in holes and under the bark.|
Remove all fruit, leaves and growth around trees – anywhere pupae may be hidden. Scrub trunks with a stiff brush and clean. Encourage wax eyes into your garden – they’re known to be one of the best pest-eating birds around.
When Spring rolls around and your gorgeous fruit trees are in full bloom, adults emerge, mate and lay eggs (once the temperature is over 15°C). The use of traps can help to determine when this happens. Leave them out as there may be another generation later on, particularly north of Auckland).
Solar lights over water or oil and milk bottle traps (see the instructions below) have been reported to be very effective by some growers.
During late Spring when the petals start to fall, larvae hatch and eat their way into your new fruit.
You can use a spray to hit the caterpillars before they disappear into the fruit.
Some recommended sprays effective against the larvae before it enters the fruit I found during my research are:
- Madex 3 is highly specific to the codling moth and organic, but also fairly pricey at around $125 for 100ml. One bottle is enough for a whole hectare, so it may be something you could team up with others to share.
- Although not sold specifically for codling moth, Kiwicare Organic Caterpillar Biocontrol is a cheaper option – the Bacillus thuringiensis it contains is effective against the codling caterpillar.
At this stage, oil sprays may also be effective in smothering the eggs, and garlic or pyrethrum sprays can be used against the adult moths, though these will also be detrimental to beneficial insects, including pollinating bees.
Repeat spray at 5-8 days intervals until four weeks after you no longer find adults in the traps.
Caterpillars feed in fruit then look for spaces to cocoon in. Some growers use tightly wound corrugated cardboard around branches and trunks, and circle below this with grease. This forces caterpillars to cocoon in the cardboard. Regularly check to monitor numbers.
Keep your traps out (replenish liquid/sticky solution every 2 weeks or so) and monitor until numbers cease in March.
There are a number of articles on Dr Google written about these pests, how to monitor them, trap them and deter them so you can research to your hearts desire. If you can’t be bothered doing that, feel free to try this version of a trap – shared with us by a wonderful client who had success with reducing these pests and the impact that they had on their feijoa crop.
How to make a codling/guava trap
Hang this mixture in your trees when they are almost done blooming, or if you’re using traps to monitor an orchard.
Replace the mixture every 2 weeks.
- Using an old milk plastic bottle, make a flap just below the shoulder facing away from the handle (the rain can’t get in to dilute the mixture, but the moths can crawl up inside).
- Make up the mixture:
- 1 cup Apple Cider vinegar
- ⅓ cup dark molasses or treacle
- ⅛ teaspoon ammonia
- 1.5ltrs water
- Fill the bottle, put the cap on and hang it by the handle using cloth strips to protect the tree limb. Hang it so the flap is facing down – to prevent rain from collecting and diluting the mix.
We’d love for you to share your experience with this solution if you try it. Good luck and long may it work to protect those feijoa babies!
If you need any assistance with pruning your fruit trees or have any questions about them, contact us and book in a visit.
Step 3: “Fill the bottle….” In the picture, the bottle is far from full. I suspect no more than 1/4 cup is needed in the trap. Some site suggest cutting 2 holes, on opposite sides of the trap for better attraction, and some say add a few drops of dish soap (unscented) to the mixture.
There are quite a few different ways of doing this. No one proven way as far as I know so feel free to experiment. Hopefully, the brainiacs of NZ Science will work out a way of eradicating this moth sooner rather than later and we can continue to enjoy bug-free feijoas. If you have a better way of dealing with these moths, feel free to share Jeff.
Comments are closed.