January 12, 2023 Chat Transcript
Recording(s) here https://www.youtube.com/playlist?list=PLajA3BBVyv1zc9xkiCSPqj3rEjW2vJ4Yb
Today’s guests: Terence Robinson, Jon Clements. Brent Arnoldussen, and Todd Einhorn
00:40:41 Anna Wallis: Welcome! If you have questions please put them in the chat. We’ll try to answer a few after each speaker, and then have more discussion at the end.
01:13:20 JM: For a severely biennial bearing HC block, is 150-200 percent still best?
01:13:29 JM: for pruning*
01:13:55 SB: What’s the plan to provide the model to WA growers?
01:14:03 JP: how do you measure carbohydrates?
01:15:17 Jon Clements: Honeycrisp is a bit of a bugaboo with that biennial bearing, really should cut dormant buds to see how many are floral to adjust pruning level…
01:16:45 Jon Clements: Carbohydrate model to WA? I presume through your AgWeatherNet?
01:17:55 Jon Clements: Carbohydrate production/depletion is a function of sunlight and temperature; and tree growth stage. Make sense?
01:20:55 SB: Are there thoughts about how climate factors such as relative humidity, wind, use of frost protection, etc, may impact the robustness of the pollen tube growth model?
01:24:58 Terence Robinson: To JM, Yes for severely biennial bearing blocks it is critical to reduce flower bud number in the “on” year to no more than 200% of the target fruit number. This is because excessive fruitlets in the first 4 weeks after bloom produce GA hormone which is the anti-flowering hormone and will ensure no flowers the next year. If however, the floral bud load is reduced to no more than 200% and you couple that with bloom thinning then the number of fruitlets can be lowered rapidly to a reasonable number which will not result in high internal GA levels and biennial bearing.
01:26:21 Terence Robinson: To SB. We plan to work with the manager of the WA weather network and Lee Kalcsits to get the model installed in WA in 2023.
01:26:45 Jon Clements: Terence and JM, so yes, and the real goal is to reduce biennial bearing tendency?
01:28:11 Terence Robinson: To JP, We do not measure carbohydrates in the trees but the model is based on experimental data where we measured photosynthesis and respiration to estimate carbohydrate production and use. The model uses temp and sunlight to grow a virtual tree and estimate internal carbohydrate status.
01:46:06 Anna Wallis: https://ag.umass.edu/fruit/fact-sheets/hrt-recipe-predicting-fruit-set-using-fruitlet-growth-rate-model
01:47:36 RC: So if I have 200 acre orchard, 100 honey, 100 gala. You are saying look only at one 10acre block and it will work for the other 90 acres?
01:49:25 Anna Wallis: https://pacman.extension.org/
01:51:40 Terence Robinson: To RC, I am not sure I understand the question. We suggest you evaluate each block an variety in your orchard not just one 10 acre block. However, as we develop digital ways to count and map orchards, I hope we can evaluate every tree in the 100 acre orchard and develop a management plan for each tree that could be communicated to workers or smart sprayers.
01:52:14 JM: RC I wouldn’t do that. Unless all your blocks are just like each other!
01:52:31 Jon Clements: RC, no, in the ideal world it would be one set of measured trees per variety per block; too onerous, right? So you are probably looking at one of the more robust options that will be discussed in following weeks…
01:54:03 RC: That’s what I thought. Just confirming. Different terminology use of “Block vs. Orchard”.
01:54:49 RC: I appreciate the comments!
02:05:10 SB: Would the carbohydrate model or Fruit set model help us understand the degree of natural “june drop” that occurs or when it would happen? Has anyone looked at “June drop” in more detail to know how growers can anticipate it better? Maybe more of WA issue than NY with higher density orchards and dwarfing rootstocks?
02:06:03 JM: Todd Einhorn that’s really exciting work!
02:07:13 Jon Clements: 👍
02:08:44 Anna Wallis: https://wsu.co1.qualtrics.com/jfe/form/SV_5aqy5G45R2jCYnQ
02:09:29 SB: Thank you Terence, that help a lot!
02:10:43 ADR: Is June drop a delayed effect of chemical thinners already applied to the block or is it a lack of fruit set?
02:12:38 Anna Wallis: Here’s the PACMAN website again for updates on this project: https://pacman.extension.org/
02:12:40 CS: does June drop also have to do with any frost damage that might have occurred? i.e. burned leaves