In 2013 I declared war against the codling moth. Why? I have two beautiful apple trees and by July 80% to 90% of the apples are riddled with nasty, little worms.
Know Your Enemy: The codling moth life cycle is pretty basic. Moths emerge mid spring, fly into apple, pear, walnut trees. They mate, lay eggs, eggs hatch, worms slink to the fruit, burrow in and make a mess. Fruit falls to the ground, worms burrow underground, pupate and wait for mid-summer to do it all again. Sometimes three times!
Disrupt The Life Cycle: I went to UC Pest Notes for advice. They advise cultural modification first. Best to have nothing growing under the tree, pick up any apples that have fallen from the tree. This helps prevent the worms from going underground and pupating. Next, thin the apples in the tree. When the apples are in clusters leave one apple (painful but it helps). Also, space the apples 4” to 6” apart. Prune some of the suckers or branches in the canopy of the tree. This eliminates any infested apples that are hard to harvest.
I cleaned under my trees, thinned and pruned. What if that's not enough? Again, UC IPM's Pest Notes! Along with some graphic photos, these guide supply you with other ways to disrupt the codling moth life cycle.
Be Relentless: So in 2013 I did it all. I cleaned, thinned, pruned, trapped, calculated and sprayed. Then repeated it again for the next codling moth generations. It was a lot of work!
Harvest time arrived and guess what? IT WORKED! I DID IT! I CRACKED THE CODE! Couldn't wait to spread the word! But, before I went on the road,
I decided to use the 2014 apple season to tighten up my presentation.
The 2014 season was a disaster! Worms in almost every apple.
Persevere: I continued through the seasons using the Pest Note's advice and added a few new steps. One year, with a minimal apple crop, I removed every apple I could reach, thinking no apples for the worms = no food, no pupa, no moths. Didn't work. Another year, I spent the summer in my trees trying to remove every infested apple. HA!
2023. I was nosing around YouTube for some apple inspiration, and I found an apple grower in Australia with a few, new to me, codling moth ideas.
This farmer layers cardboard mulch under the tree. Thinking, if the pupa can't emerge as moths, it might reduce the worm population. And when the moths are flying in the tree (a few hours in the evening for 2 or 3 days) this same smart farmer lightly sprays the tree in hopes of wetting the moth's wings to inhibit their flying and egg laying.
Well, I can do that. So, this year I covered all the steps from previous years and added the cardboard mulch and water spray steps.
The first generation for this year has passed. I see little damage. After the second and possibly third generation come and go, victory? We will see.
Stay tuned.
UC ANR's pest notes for codling moth can be found here: https://ipm.ucanr.edu/PMG/PESTNOTES/pn7412.html