[apple-crop] Fw: Penn State Extension Fact Sheet on Critical Temperatures for Various Fruit Crops

2016-04-04 Thread Evan B. Milburn 


 On Monday, April 4, 2016 9:16 AM, Tara A Baugher  wrote:
 
 

  Growers – a number of you have been asking about 
potential impacts from the freezing temperatures already experienced and in the 
forecast, so I’ve pasted in Rob’s fact sheet from thePenn State Extension Tree 
Fruit Production website. Note that prolonged cool weather tends to increase 
bud hardiness during the early stages of bud development.  ~Tara Critical 
Temperatures for Various Fruits  The temperature at which fruit buds are 
injured depends primarily on their stage of development. As flowers begin to 
swell and expand into blossoms, they become less resistant to freeze injury.   
Examples of stages of fruit bud development: top left - apple tight cluster; 
top right - apple pre-bloom; lower left - sweet cherry first white; lower right 
- peach pink. Not all blossoms on a tree are equally tender. Resistance to 
freeze injury varies within trees as it does between orchards, cultivars, and 
crops. Buds that develop slowly tend to be more resistant. As a result, some 
buds are usually killed at higher temperatures, while others are resistant at 
much lower temperatures. The table below shows the average temperatures 
required to kill 10 percent and 90 percent of buds if they are exposed for 30 
minutes. Consideration should also be given to weather conditions preceding 
cold nights. Prolonged cool weather tends to increase bud hardiness during the 
early stages of bud development. 
| Stage of Development  | 10% kill  (°F)  | 90% kill  (°F)  |
|  |
| Applesa  |
| Silver tip  | 15  | 2  |
| Green tip  | 18  | 10  |
| ½-inch green  | 23  | 15  |
| Tight cluster  | 27  | 21  |
| First pink  | 28  | 24  |
| Full pink  | 28  | 25  |
| First bloom  | 28  | 25  |
| Full bloom  | 28  | 25  |
| Post bloom  | 28  | 25  |
| Peaches  |
| First swelling  | 18  | 1  |
| Calyx green  | 21  | 5  |
| Calyx red  | 23  | 9  |
| First pink  | 25  | 15  |
| First bloom  | 26  | 21  |
| Full bloom  | 27  | 24  |
| Post bloom  | 28  | 25  |
| Pearsb  |
| Scales separating  | 15  | 0  |
| Blossom buds exposed  | 20  | 6  |
| Tight cluster  | 24  | 15  |
| First white  | 25  | 19  |
| Full white  | 26  | 22  |
| First bloom  | 27  | 23  |
| Full bloom  | 28  | 24  |
| Post bloom  | 28  | 24  |
| Sweet cherries  |
| First swelling  | 17  | 5  |
| Side green  | 22  | 9  |
| Green tip  | 25  | 14  |
| Tight cluster  | 26  | 17  |
| Open cluster  | 27  | 21  |
| First white  | 27  | 24  |
| First bloom  | 28  | 25  |
| Full bloom  | 28  | 25  |
| Post bloom  | 28  | 25  |
| Apricots  |
| First swelling  | 15  | -  |
| Tip separates  | 20  | 0  |
| Red calyx  | 22  | 9  |
| First white  | 24  | 14  |
| First bloom  | 25  | 19  |
| Full bloom  | 27  | 22  |
| In the shuck  | 27  | 24  |
| Green fruit  | 28  | 25  |

   Adapted from 1989 Spray Guide for Tree Fruits in Eastern Washington. 
Bulletin EBO419. E. H. Beers, coordinator.
   - For Red Delicious. Golden Delicious and Winesap are approximately 1 degree 
hardier. Rome Beauty is 2 degrees hardier, except after petal fall when all 
cultivars are equally tender.
 a.  For Bartlett. D’Anjou is similar but may bloom earlier and therefore 
may be more tender than Bartlett at the same date.    Source: Penn StateTree 
Fruit Production Guide. (Updated January 2016). Contact Information  Robert 
Crassweller
   - Professor of Tree Fruit
 Email:r...@psu.edu Phone: 814-863-6163    You received this email because you 
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College of Agricultural Sciences
The Pennsylvania State University
Ag Administration Building
University Park, PA 16802

 
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Re: [apple-crop] Freeze/Frost Damage

2016-04-04 Thread Peter Werts 
You may find this of interest.  I read through it a few years back and found
some helpful information.  

 

"Frost Protection Fundamentals, Practices and Economics", 

* Table of contents and background information:
http://www.fao.org/docrep/008/y7223e/y7223e00.HTM 

* Direct link to the PDF: http://www.fao.org/3/a-y7223e.pdf

 

 

 

 

Thanks,

 

Peter

 

 

=

Peter Werts

Specialty Crops Project Manager

IPM Institute of North America, Inc.

1020 Regent St. 

Madison WI 53715

Office: 608 232-1410

Cell: 612 518-0319

Fax: 608 232-1440

  pwe...@ipminstitute.org

  www.ipminstitute.org

 

 

 

From: apple-crop-boun...@virtualorchard.net
[mailto:apple-crop-boun...@virtualorchard.net] On Behalf Of Christina M.
Herrick
Sent: Monday, April 4, 2016 9:14 AM
To: apple-crop@virtualorchard.net
Subject: [apple-crop] Freeze/Frost Damage

 

Does anyone have any losses from the latest cold snap? Dave and Christina
from American Fruit Grower would like to talk to you about it. Send Dave
Eddy (de...@meistermedia.com  ) or Christina
Herrick (cmherr...@meistermedia.com  ) a
note.

 

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