Trees in Central Washington sustained a lot of trunk damage in November 2010, an event now called the "Thanksgiving freeze." Daily high temperatures that had been 55 to 60 Fahrenheit (15C) dropped to as low as -5 to -18F (-23C). The trunks of many trees were not ready for this, so we saw a lot of discoloration under the bark the next spring.
The most seriously injured trees showed symptoms the first spring, 2012, with bark splitting and peeling. Trees flowered, began to grow foliage and collapsed by the middle of summer. Many trees that were damaged did not die in 2012, but they were obviously suffering from the effects of the cold snap. I saw another wave of trees die in 2013 as the cold damaged trunks were attacked by secondary organisms, especially those that cause cankers. Perennial canker seems to be one of the most dangerous, as it continues to spread on the trunk when aggravated by woolly apple aphid. Last week I saw my most recent case of trees dying from the 2010 event, due to what I believe is perennial canker. This problem is widespread, it is a serious problem in some of the low spots and orchards that experienced temperatures even lower than those recorded by remote weather stations. Most of you have probably already experienced this sort of thing in the past. However, if you haven't, please be aware that you could lose trees for two or three more years if you have a winter severe enough to cause bark splitting on tree trunks. Tim Smith Regional Extension Specialist WSU -- Wenatchee Washington From: [email protected] [mailto:[email protected]] On Behalf Of Peck, Greg Sent: Monday, March 17, 2014 6:47 PM To: Apple-Crop Subject: Re: [apple-crop] Southwest Injury Thanks to all those who responded to my email. Yes, for SWI (and most things in orchard systems), "an ounce of prevention is worth a pound of cure". For those who missed it, there was a long discussion on trunk painting last year: http://www.mail-archive.com/[email protected]/msg02242.html >From reading all the responses, and considering the lack of tree availability >for replanting this spring, it seems to me that it might be worth trying the >salvage some of less damaged trunks by closing up the split bark. Debbie's >rule-of-thumb sounds reasonable and would give growers some idea as to when to >just move on. As Debbie also pointed out, the wounds could be an entry site for borers. The wound sites might also be a location for WAA colonies, which seem to have gotten worse under our BMSB-focused insecticide programs. I guess the exposed tissue could also be an entry point for herbicides. While bridge grafting is probably technically feasible, I'm getting the sense that it may not be worth the time. It's up to each grower to make that decision, but I'd be hesitant to say it's an economically feasible choice for large blocks of high-density trees unless you have a talented grafter on-staff. Greg :::::::::::::::::::::::::::::::::::::::::::::::::::: Gregory Michael Peck, Ph.D. Assistant Professor of Horticulture Virginia Tech Alson H. Smith, Jr. Agricultural Research and Extension Center 595 Laurel Grove Road Winchester, VA 22602 USA 540/869-2560 ext 19 [email protected]<mailto:[email protected]> arec.vaes.vt.edu/alson-h-smith www.anr.ext.vt.edu/tree-fruit/<http://www.anr.ext.vt.edu/tree-fruit/> blogs.ext.vt.edu/tree-fruit-horticulture<http://blogs.ext.vt.edu/tree-fruit-horticulture> www.facebook.com/VtechPomology<http://www.facebook.com/VtechPomology> On Mar 17, 2014, at 10:05 AM, Deborah I. Breth <[email protected]<mailto:[email protected]>> wrote: Greg, You could use the rule of thumb for canker surgery and if more than a 1/3 of the circumference is interrupted, likely nothing you can do. But if less than 1/3, try to cut the dead bark away using a straight linoleum cut so there is no shelter (under the split bark) that will attract and support the borers. The callus will be more uniform and heal that part of the trunk. There will always be the unknown with wood rotting fungi invading the exposed heart wood. Good luck. Deborah I. Breth Cornell Cooperative Extension - Lake Ontario Fruit Program Team Leader and IPM Specialist in Tree Fruit and Berries 12690 Rt. 31 Albion, NY 14411 mobile: 585.747.6039 phone: 585.798.4265 x 36 fax: 585.798.5191 email: [email protected]<mailto:[email protected]> LOF website -----Original Message----- From: [email protected]<mailto:[email protected]> [mailto:[email protected]] On Behalf Of [email protected]<mailto:[email protected]> Sent: Sunday, March 16, 2014 12:30 PM To: Apple-crop discussion list Subject: Re: [apple-crop] Southwest Injury Greg; We get the same damage here in Southern California, but from sunburn, not Southwest Injury. But the damage is the same, dead cambium layer and sunken bark. Besides robbing vigor from the tree, here it also attracts borers who take advantage of the tree's inability to sap out the maggot, and exploit the edges of the injury. The wounds will not heal; they may eventually be covered by cambium growing from either side, like a pruning stump is covered over. Bridge grafting is easier on shorter injuries like vole and rabbit damage; the problem with SWI is that the wounds are long and narrow. Cutting the tree off and letting a latent bud sprout may be a viable option depending on the damage, but you will have to weigh the loss of productivity against how long it would take if you just pruned the tree hard and let it try to heal the SWI. Painting trunks white, especially with an airless sprayer, seems way less trouble than any of this. Kevin Hauser Kuffel Creek Apple Nursery Riverside, California Nakifuma, Uganda, East Africa On Sun, 16 Mar 2014 10:42:00 -0400, "Peck, Greg" <[email protected]<mailto:[email protected]>> wrote: Apple-Crop participants, Like everyone else in the Eastern half of the US, we've had a particularly cold and snowy winter in Virginia. Not surprisingly, I am starting to hear reports about Southwest injury to young trees. While there is a lot of information available on how to prevent southwest injury, I have not been able to find much information on how to deal with the trunks after the damage has been done. Typically, growers in Virginia have do not paint trunks with latex paint, but many will probably reconsider that decision in future years. Many trees are probably not going to make it, but I'm wondering if anyone has experience trying to save some of the less severely injured trees with bridge-grafts. How about wrapping the bark with grafting tape to try to get the wounds to heal? (I'm guessing that this will have a low success rate because the tissue has already dried out.) Depending upon how far into the rootstock the split extends and the age of the tree, we might also try cutting off the scion and hoping an advantageous bud breaks dormancy. Any other suggestions from those who have to deal with Southwest Injury on a more annual basis? Thanks, Greg :::::::::::::::::::::::::::::::::::::::::::::::::::: Gregory Michael Peck, Ph.D. Assistant Professor of Horticulture Virginia Tech Alson H. Smith, Jr. Agricultural Research and Extension Center 595 Laurel Grove Road Winchester, VA 22602 USA 540/869-2560 ext 19 [email protected]<mailto:[email protected]><mailto:[email protected]> arec.vaes.vt.edu/alson-h-smith<http://arec.vaes.vt.edu/alson-h-smith> www.anr.ext.vt.edu/tree-fruit/<http://www.anr.ext.vt.edu/tree-fruit/> blogs.ext.vt.edu/tree-fruit-horticulture<http://blogs.ext.vt.edu/tree-fruit-horticulture><http://blogs.ext.vt.edu/tree-fruit-horticulture> www.facebook.com/VtechPomology<http://www.facebook.com/VtechPomology><http://www.facebook.com/VtechPomology> _______________________________________________ apple-crop mailing list [email protected]<mailto:[email protected]> http://virtualorchard.net/mailman/listinfo/apple-crop _______________________________________________ apple-crop mailing list [email protected] http://virtualorchard.net/mailman/listinfo/apple-crop
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