Organic Apple Codling moth treatment assessment - 2024

General Fruit Growing
1

This is the third season I’ve done a detailed assessment of my apple’s organic codling moth treatment. I thought I’d start a new dated thread (here are the previous results and discussion)…

In 2021 I had 85% clean apples on my test tree and in 2022 it was 79%. Clean means no or only a superficial surface sting that didn’t result in a worm burrowing into the apple. Either would be fine to eat out of hand or store long-term.

This year I had 96% clean apples with spraying and 93% with bagging.

I made some changes in the treatments but was also lax about spray timing - I generally sprayed every 10-14 days versus the recommendation of every 7 days. Details below.

Honeycrisp Tree 1 - bagging only with white mesh organza bags

  • Off biennial production year but still produced some apples
  • No spraying of this tree
  • 42 bagged apples harvested - 39 had no damage or had a superficial sting - 93% effectiveness
  • BUT…37 of 39 sustained a kind of skin callusing from rubbing on the bag that made them less desirable - I would want to cut it off before eating (see photo at end)
  • I bagged perhaps 50 other apples of around 10 grafted varieties on other trees that had no bag damage - something about honeycrisp skin in particular is susceptible.

Honeycrisp Tree 2 - spray only

  • Full production year - 362 apples after multiple thinnings
  • Spray schedule - less than recommended at 10-14 day intervals
    • 6/5 spinosad + dormant oil
    • 6/16 spinosad + canola oil + fungicide + insecticidal soap
    • 6/27 spinosad + canola oil
    • 7/12 spinosad
    • 7/22 spinosad + pyrethrin + canola oil
    • 8/1 spinosad + fungicide + canola oil
    • 8/15 spinosad + canola oil
    • 8/28 spinosad → I’m supposed to keep protected through 9/15
  • Results
    • 298 perfect, 51 sting, 13 damaged - 96% effective
    • Slightly skewed because I didn’t count drops before I harvested

My assessment:

  • Overall, bagging is a lot of work and not worth the effort…it’s curious that honeycrisp alone is susceptible to the skin callusing. The only reason I might do it again is to provide greater protection on grafted apples I’ve not yet tasted as insurance.
  • Even lax spraying at 10-14 day (or more) intervals worked very well - 96% effective.
  • Canola oil may or may not do anything but it’s cheap, doesn’t hurt, and maybe helps with both smothering and acting as a sticker
  • I realize I sprayed spinosad more than the label recommends in a season, but I added pyrethrin in one batch to try to offset the development of moth resistance

Resources:
The Utah State University extension office has an integrated pest management newsletter that tells you when and what to spray by county based on different models for egg hatch. Example here.

If you made it this far, I do have a question. I exchanged a couple of Facebook messages with Hocking Hills orchard in central Ohio (a popular u-pick orchard) about their spray methods. They said “neem oil and wettable sulfur” but our extension agent had never heard of that for codling moth. Anyone else have input about it?

Appendix
Organza bag skin callusing

honeycrisp
honeycrisp1920×1440 290 KB

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96% is really impressive, especially since you have actual pest pressure. It’s good to know you can get good result with organic sprays even if you don’t follow the schedule very strictly.

These are probably the most harmless-sounding sprays the orchard could think of. There’s a chance they didn’t want to mention an actual insecticide because so many people feel that insecticides are evil.

People are really happy eating an orange with 83 different pesticides in it (actual number from food control testing). Some of the same people would be really mad to hear glyphosate was sprayed around the tree nine months before the oranges were picked and would completely lose their mind to hear the actual results of the food test.

It only takes one person screaming their lungs out on social media about how evil the orchard is to reduce a U-pick’s profit by hundreds or thousands of dollars.

I don’t sell any fruit and don’t even have enough for family and friends. I still tell people I spray with foliar fertilizer (actually true). It only took one person seeing me spray and going crazy to stop me from talking about pesticides to strangers. Imagine how bad it is for an actual u-pick orchard whose business could be destroyed by uninformed people.

Everybody I give fruit to knows what I spray with, and that my fruit are sprayed much less than what people buy in the store. However, random people asking what I spray with may be looking for a fight and I’m too old for this.

If the location wasn’t certified organic then they simply lied to protect their business. If you want an honest answer, ask an orchard whose profitability isn’t directly dependent on how they are perceived by random people.

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