Reno, NV
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Managing Codling Moth
in Home Landcapes
Sign of a codling moth larva
that has chewed into an apple.
©Aspect Tree Care
Codling moth is a significant pest of fruit trees in Northern Nevada. The "worm" you might find in your apples is actually its larva, or caterpillar. It can also affect peaches, pears, plums, quinces, walnuts, crabapples, and hawthorns.
It is not an easy pest to control. It requires several different methods at key times of the year. Eradication is very difficult, but there are some easy steps to take to suppress it to a tolerable level. We are happy to provide these services for you as well.
Below, I'll list the steps of the most effective ways to control codling moth when you only have a few backyard trees, which is different from how you'd manage a home orchard or commercial orchard. It's best if you start early in the fall of the previous year, but if the growing season has already begun, you can also start at any step.
For more information, I included links to some excellent resources down below.
Step 1: In the fall, allow leaf litter litter and other garden debris to accumulate around the base of your fruit trees.
One of the easiest and most effective ways to control codling moth is to reduce that amount of the insects that can survive the winter. Since codling moth larvae drop from the tree at the end of the season and take shelter in leaf litter, you can intentionally leave this debris to attract the overwintering larvae, with the plan to remove it long before spring begins.
Step 2: In mid-winter, thoroughly clean up the leaf litter around your fruit trees.
During the middle of winter (January is best), remove all of the leaf litter. You should also remove other loose organic material that may contain overwintering larvae, such as loose bark on lower tree trunks, and debris that is caught in tree crotches and cavities. Coarse wood chip mulch spread evenly on the ground is ok to stay. If you really want to be thorough, you can use compressed air or a stiff wire to inspect for, and remove, overwintering larvae from bark crevices.
Step 3: In late winter/early spring, prune your fruit trees to maintain size, shape, and structure, and put out codling moth traps for monitoring.
It's best to prune fruit trees in the late winter or early spring regardless of whether you're trying to control a pest problem. If you anticipate needing to spray for codling moth, regular pruning makes it easier to get better spray coverage which makes the spray more effective. Around this time, you'll want to put out traps so you'll know when you need to start spraying. You can get codling moth specific traps at Moana Nursery
Step 4: When adult codling moths are present or when fruit is beginning to form, begin spraying with an OMRI Listed® organic pesticide, and prune again to thin fruit.
When your traps begin to catch moths, or when fruit starts to form, it's time to start spraying. I recommend Captain Jack's Deadbug Brew, which is an OMRI Listed® organic spray. It can be sprayed up to 6 times per year, every 10-14 days. Just make sure to wait 7 days after spraying before harvesting the fruit.
A note about Pesticide sprays:
The most effective pesticides, contact or systemic, are usually synthetic and/or unsafe to use on edible crops. Insecticides approved for fruit trees include botanicals, biorationals, and OMRI Listed® organic insecticides, and these are inherently less effective. Timing, thorough coverage, and repeat applications are crucial.
Dormant oil is ineffective. While dormant oil is effective on aphids, scale, and other insects because it disrupts the crawler stage, it doesn't work on codling moth. eggs are laid on the surface of fruit almost as soon as the fruit begins to form.