On Monday, April 4, 2016 9:16 AM, Tara A Baugher <ta...@psu.edu> wrote:
<!--#yiv1548931252 filtered {font-family:Wingdings;panose-1:5 0 0 0 0 0 0 0 0 0;}#yiv1548931252 filtered {font-family:Wingdings;panose-1:5 0 0 0 0 0 0 0 0 0;}#yiv1548931252 filtered {font-family:Calibri;panose-1:2 15 5 2 2 2 4 3 2 4;}#yiv1548931252 filtered {font-family:Tahoma;panose-1:2 11 6 4 3 5 4 4 2 4;}#yiv1548931252 p.yiv1548931252MsoNormal, #yiv1548931252 li.yiv1548931252MsoNormal, #yiv1548931252 div.yiv1548931252MsoNormal {margin:0in;margin-bottom:.0001pt;font-size:11.0pt;font-family:"Calibri", "sans-serif";}#yiv1548931252 a:link, #yiv1548931252 span.yiv1548931252MsoHyperlink {color:blue;text-decoration:underline;}#yiv1548931252 a:visited, #yiv1548931252 span.yiv1548931252MsoHyperlinkFollowed {color:purple;text-decoration:underline;}#yiv1548931252 p.yiv1548931252MsoAcetate, #yiv1548931252 li.yiv1548931252MsoAcetate, #yiv1548931252 div.yiv1548931252MsoAcetate {margin:0in;margin-bottom:.0001pt;font-size:8.0pt;font-family:"Tahoma", "sans-serif";}#yiv1548931252 p.yiv1548931252MsoListParagraph, #yiv1548931252 li.yiv1548931252MsoListParagraph, #yiv1548931252 div.yiv1548931252MsoListParagraph {margin-top:0in;margin-right:0in;margin-bottom:0in;margin-left:.5in;margin-bottom:.0001pt;font-size:11.0pt;font-family:"Calibri", "sans-serif";}#yiv1548931252 span.yiv1548931252EmailStyle17 {font-family:"Calibri", "sans-serif";color:windowtext;}#yiv1548931252 span.yiv1548931252BalloonTextChar {font-family:"Tahoma", "sans-serif";}#yiv1548931252 .yiv1548931252MsoChpDefault {font-family:"Calibri", "sans-serif";}#yiv1548931252 filtered {margin:1.0in 1.0in 1.0in 1.0in;}#yiv1548931252 div.yiv1548931252WordSection1 {}#yiv1548931252 filtered {}#yiv1548931252 filtered {}#yiv1548931252 filtered {}#yiv1548931252 filtered {}#yiv1548931252 filtered {}#yiv1548931252 filtered {}#yiv1548931252 filtered {}#yiv1548931252 filtered {}#yiv1548931252 filtered {}#yiv1548931252 filtered {}#yiv1548931252 filtered {}#yiv1548931252 filtered {}#yiv1548931252 filtered {}#yiv1548931252 filtered {}#yiv1548931252 filtered {}#yiv1548931252 filtered {}#yiv1548931252 filtered {}#yiv1548931252 filtered {}#yiv1548931252 filtered {}#yiv1548931252 filtered {}#yiv1548931252 filtered {}#yiv1548931252 filtered {font-family:Symbol;}#yiv1548931252 filtered {font-family:"Courier New";}#yiv1548931252 filtered {font-family:Wingdings;}#yiv1548931252 filtered {font-family:Wingdings;}#yiv1548931252 filtered {font-family:Wingdings;}#yiv1548931252 filtered {font-family:Wingdings;}#yiv1548931252 filtered {font-family:Wingdings;}#yiv1548931252 filtered {font-family:Wingdings;}#yiv1548931252 filtered {font-family:Wingdings;}#yiv1548931252 ol {margin-bottom:0in;}#yiv1548931252 ul {margin-bottom:0in;}-->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 are subscribed to the Fruit Times for PA fruit growers (FRUIT-TIMES-L) mailing list. If you would like to unsubscribe from this list, simply send an email to mailto:fruit-times-l-unsubscribe-requ...@lists.psu.edu?Subject=Unsubscribe. No subject or message is necessary in the email. 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