Knowledgebase
Organic apples and codling moths #865815
Asked April 24, 2024, 10:01 PM EDT
We have a mature apple tree that we attempt to harvest organic apples. The codling moths have been a big problem for us every year. We tried spinozide last year and it was the worst ever. Have had some success with neem oil sprayed every 2 weeks or so (kind of expensive and time consuming). What is the best way to solve this codling moth issue? Is there a better way to prepare the ground underneath the tree? We are thinking of putting down clean pea gravel after preparing the soil with a dose of neem oil. Does milky spore do anything for codling moth grubs? Any other ground preparations you suggest? We also plan to try the kaolinite clay spray this year. And other suggestions are much appreciated.
Jefferson County Colorado
Expert Response
Coddling moths can be a major pest of apple production, as you've experienced. The attached CSU Fact Sheet below discusses several cultural controls, including fruit thinning, prompt removal of infested fruit, and clearing the area around the trunk where the larvae drop to pupate in the soil. This fact sheet mention trunk banding and fruit bagging as additional control strategies. We found no extension resources indicating that milky spore or neem oil could control the larvae or pupae on the ground. But the Michigan State U publication does discuss 1) neem oil applied to eggs and 2) Entomopathogenic nematodes being studied as a ground drench. We do not know the source of such nematodes or whether they have proven to be effective. Your idea to put gravel around the tree might end up providing cover, so clear ground would be more effective.
Spinosad is considered effective but must be applied about every 7 days and only for a limited number of times as the label indicates. If it were sprayed after petal fall it might reduce the egg laying of the first generation or spraying on developing fruit later in the summer might reduce infestation by the second CM generation.
That clay spray can work to minimize access for the second generation of egg laying and larvae if you cover each fruit fully. (The first generation of eggs are laid in or near the blossoms and larvae develop within the fruit as it grows so clay does not reduce that infestation.) Having used that years ago on my own apple trees, I found it very messy and not worth the trouble (and it can clog hand sprayer nozzles). But you might try it this season.
You can communicate directly with the jeffco extension plant diagnostic help desk via e mail: <personal data hidden>; include a notation that the query relates to AskExtension question #0135736.
https://extension.colostate.edu/topic-areas/insects/codling-moth-control-in-home-plantings-5-613/
https://www.canr.msu.edu/news/organic_management_of_codling_moth
Pat B
Sent from my iPad
On May 1, 2024, at 3:39 PM, Ask Extension <<personal data hidden>> wrote:
