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If you think losing one home-grown apple tree to disease is disappointing, imaging having your healthy young orchard turn into a mess of dying apple trees. This is happening to orchards across North America and researchers can't figure out why. So far, the phenomenon called Sudden Apple Decline (SAD) or Rapid Apple Decline, has devastated orchards in Ontario, New York State, Washington and Pennsylvania.
In this episode of The Urban Forestry Radio Show, Kari Peter, Ph.D of Penn State Fruit Research and Extension Centre, explains how she has witnessed this problem first hand. One day the trees in her research orchard looked perfectly healthy. A few days later their leaves went yellow. Then, within two weeks, entire blocks of her test orchards were filled with dying apple trees. The trees were dead within a matter of weeks - many of them had a sad-looking harvest dangling off their lifeless branches.
Apple trees die for many reasons and diseases like fireblight can also spread quite rapidly. But this problem, which is called Sudden Apple Decline (SAD) or Rapid Apple Decline can be identified when the dying apple tree seems to be infected around its graft union. You might see the bark at the graft union peeling off. Then the problem moves up the tree, killing the tree, but the root stock will still be alive and well and unaffected by the disease.
Most of the dying apple trees are younger trees between 2 and 8 years old. It seems bigger, older apple trees are more resilient. They can survive the problem. Or maybe they don’t get infected at all.
Researchers are now scrambling to discover why Sudden Apple Decline is spreading. Is it a virus? Is it the result of herbicide damage? Is there a fungal element? What role does stress or winter damage play? Why is it that most of the dying apple trees are grafted onto M9 dwarfing root stock?
Researchers also don’t know if it’s only affecting tightly-planted high density orchards. Or are young apple trees dying in the urban setting as well?
Experts including Kari Peter, Ph.D. are now collaborating to get to the bottom of the problem to prevent more tree casualties and the devastating financial losses that growers are experiencing as a result. Many of these research teams have applied for grants and are waiting for funding so that they can dig deeper, identify the problem and find the solution.
The host of the Urban Forestry Radio Show and Podcast is Susan Poizner of the fruit tree care education website www.orchardpeople.com and the author of the award-winning fruit tree care book Growing Urban Orchards. You can listen to previous episodes of The Urban Forestry Radio Show and Podcast at www.orchardpeople.com/podcast and you can subscribe to the iTunes podcast.
Tune into The Urban Forestry Radio Show LIVE by going to RealityRadio101.com on the last Tuesday of every month at 1.00 pm Eastern Time and email your questions in during the show to [email protected] This show covers fruit trees, food forests, permaculture and arboriculture. After the live broadcast, archived podcasts are available at www.orchardpeople.com/podcast.
The Urban Forestry Radio Show and Podcast is brought to you by our Gold Sponsor, Stark Bro's Nurseries and Orchards . Our bronze sponsors include Whiffletree Nursery, Earth Alive, Acti-Sol and Mark's Choice.
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