2022 Champlain Valley Rescue Thinning Recommendations

Dr. Terence Robinson, Cornell AgriTech, Geneva, New York and Mike Basedow, CCE-ENYCHP, Champlain Valley, New York

The following is a summary of yesterday’s meeting. The recording is available on our team YouTube page here: https://www.youtube.com/watch?v=_jo3mUlMk9o&feature=youtu.be

  • From visiting orchards early this week, and from the results of our fruit growth model measurements, we expect that good thinning was achieved in much of the Champlain Valley at this point, so hopefully not much rescue thinning will be needed. There may however still be a few heavy blocks here and there.
  • If you aren’t sure if you still need some additional thinning on a particular variety, you can assess your crop load by counting fruit on five representative trees.
  • If on five trees your crop load is currently more than 2 times your target number or higher, a rescue spray is warranted.
  • If on five trees your crop load is currently 1.5 to 2 times your target number, then use your best judgement as to whether you need to spray again or not.
  • If on five trees your crop load is less than 1.5 times your target number, do not spray a rescue thinner.
  • If you determine you still need additional thinning, use the degree day column in the carbohydrate thinning model to determine when to apply. The ideal timing is 300-350DD after full bloom. This correlates to yesterday through this Thursday in the Peru area. Check the model to determine the best timing for your site.
  • Where kings are 18mm already, do not wait, as fruit size will increase rapidly, and will soon be unresponsive to most thinners.
  • High temperatures will likely be in the low to mid-70s throughout the remainder of this window, and there will likely be a carbohydrate surplus. This should give mild thinning. Again, we recommend running the model for your site the day you plan to apply, just in case the weather changes.
  • We recommend nozzling the sprayer so that 100% of the spray is directed to the top half of the trees. Remember to adjust your TRV calculations for your lower spray volume when you shut off those bottom nozzles. Do NOT concentrate up your oil and Sevin. Do not use oil if you have applied Captan within the last 5-10 days, or are planning to apply Captan within 5-10 days following the oil application. 
  • Rate Recommendations:
    • Honeycrisp – Use Maxcel at 48oz TRVD basis + 1 pt Carbaryl + 1 pt oil
    • Cortland – Maxcel at 48 oz TRVD basis + 1 pt oil
    • Gala and Fuji – Use Maxcel at 64 oz TRVD basis + 1 pt Carbaryl + 1 pt oil
  • If you would like to try Accede on a small area, call Mike ASAP. We might be able to find a small amount for you to try on a trial basis.