More than you may want to know about frost and fruit buds

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Well, more than I want to read at this point. Reminds me too much of my work at A&M.


Hey, it’s raining here!. Here’s some more for you FN.

I scanned and read parts of it. One takeaway I got (from a management perspective) is that trees w/ high carbohydrate reserves are more tolerant of frosts/freezing.

I thought it was interesting they mentioned girdling increases carbs and decreases water making the tree more freeze tolerant above the girdle (but less freeze tolerant below).

In general I expect trees with more carbohydrate reserves are probably more disease and bug resistant as well.

While I am a scientist by trade I didn’t have the patience to get into that article. Usually I read the abstract or conclusion and find some points worth digging out of the paper, but this paper had no real points there.

The original posted document has 300 documents referenced. 30 days and 30 nights of rain won’t be enough time.

I’m no scientist or student striving for a grade, I mostly read conclusions after scanning methods. Sometimes they also include a discussion that is useful. The second document is different in that it is a review of research- the last couple of paragraphs covers the likely lack of efficacy of spray products there’s been some discussion of here lately.

To get what I need doesn’t take that much effort. I’m happy I can pull this stuff up for free- a lot of work goes into these papers.

That’s more my speed at this point and a worthwhile read if one needs the info. But it’s not raining here.


Hey the 2nd paper has an interesting conclusion relative to the topic of sprays to kill ice nucleating bacteria:

Rarely have there been success stories from growers using chemical sprays against frost damage. Most positive results are reported in well-controlled university experiments. For example, the use of chemical sprays (e.g. zinc; copper; antitranspirants) was reported to offer no measurable benefit in limited scientific investigations on deciduous tree crops in Washington State (USA) (Evans, 2000). Likewise, sprays to eliminate “ice nucleating” bacteria have not been found beneficial because of the great abundance of “natural” ice-nucleation materials in the bark, stems, etc. which more than compensate for any lack of bacteria (Evans, 2000). The results from chemical sprays for frost protection are clearly mixed. Part of the problem is the large variation in INA bacteria on different crops. For example, citrus and grapevines tend to have smaller concentrations of INA bacteria, whereas deciduous trees and grasses tend to have high populations. Some of the variation in results is due to these differences. In addition, the timing and concentration of chemical sprays are still under investigation. In summary, it is well known that INA bacteria are involved in ice nucleation on plants, and therefore reducing concentrations of INA bacteria can provide some measure of frost protection. However, more research is clearly needed to determine if and when control of INA bacteria is beneficial, and which management will give acceptable results.

This makes me feel better as I did not spray any copper etc during my recent freezes. I do regret not flaming my apricots, in future years they are going to get 500,000 BTU of warmth on cold nights.

I’m not reading any of this stuff, nor getting involved in this discussion,
and BTW it’s raining here.

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Its raining here too. Just got the drip up and running, so I should have known it was going to rain.

I only got as far as the first paragraph before I learned a key point.

“During advection frosts, the lowest temperatures are usually observed on the middle and higher portions of hillsides”

“In radiation frosts, higher night-time temperatures are observed on hilltops and on upper middle sections of hillsides that are free from obstacles to block cold air drainage”

Fortunately for me, most of my frost are radiation. By luck, I sighted the orchard on the best site I had available for these type of frost. Unfortunately its the worst site possible for advection frost.

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Blueberry, did you get an an advection frost or a radiant frost post bloom? We had a radiant frost last night here.

No rain here. Typing from my truck at the orchard. Apologize for mistakes. I hate auto correct.

Scott, I read the second paper as inconclusive on ina sprays. I posted this chapter a few days ago on another thrrad.

Weekly sprays with copper did make a difference. The more I consider everything, the more I think copper could help.

Copper is the only spray labeled for frost, which suggests the manufacturer had to do some research to validate the claim for registration.

Also, Blueberry’s post that a research station showed a significant difference in blocks sprayed with or without copper has my attention.

Do elaborate.

I posted the email I got last week from the NCSU research farm. Its not a valid trial just an observation based on results from one year on peaches. They also tested Promalin on apples but not in a valid trial.

Here is the original email: from 4/5 after our first big frost:

The following Promalin information was sent from J.D. Obermiller with the NCSU Res. Ser.

Promalin for frost/freeze rescue.
The rate is 1pint per 100 gallons. 100 - 150 gpa sprayed within 24-48 hours post freeze.
Label has 24 hrs, but our results in 2012 and 2014 had equal results up to 48, and
even good numbers out to 96 hours. That was good news since it’s so hard for most
growers to spray everything in a day.
Another frost injury protection material you may want to try is Kocide 3000. In 2015
some local peach blocks showed good results using Kocide 3000. Orchard temperatures dropped to 20 deg. Adjacent blocks without Kocide had very little fruit. It was used 24 hrs. prior to frost at 2lbs./ac. The following information comes from the Kocide MSDS.
Application of KOCIDE® 3000 made to all crops listed on this label at rates and stages of growth indicated on this label, at least

24 hours prior to anticipated frost conditions, will afford control of ice nucleating bacteria (Pseudomonas syringae

herbicola and

Pseudomonas fluorescens) and may therefore provide some protection against light frost. Not recommended

for those geographical areas where weather conditions favor severe frost.

Sincerely, Marvin



Great, thanks.

We normally get a radiant frost. No winds and temperature inversion with the cold air trapped at ground level. The larger growers use wind machines to break the inversion and pull the warm into the orchard.

I recorded slightly over a 1 degree temp change in just a few feet of height in the apples last week