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nafex - Re: [NAFEX] lime sulfur(apricot tree rescue)

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  • From: "Dennis Norton" <dmnorton@royaloakfarmorchard.com>
  • To: "North American Fruit Explorers" <nafex@lists.ibiblio.org>
  • Subject: Re: [NAFEX] lime sulfur(apricot tree rescue)
  • Date: Thu, 6 Apr 2006 17:24:25 -0500

Chris,
Canker, gumosis or bacterial canker are common infections in stone fruits, especially peach and apricot. Bacterial canker is, in my opinion, the worst. But any stone fruit tree that has gum oozing (gumosis) may not necessarily have a disease, although it usually does. The oozing gum is also the tree's way of protecting itself from any bark damage and can be quite common on peaches and apricots. Unfortunately the gum is usually a sign of progressively worse problems and it is hard to know without lab tests. The University of Wisconsin has a great pathology lab and the costs are minimal. You can find them at http://pddc.wisc.edu/index.html or google "plant disease diagnostic clinic" for your state's clinic.

If it is gumosis, there is no chemical control for the disease. Destroying or removing dead trees and prunings can be helpful in reducing inoculum. It can spread through pruning shears, rain, weeds or wind. A tree can survive for several years with the disease, but will eventually lose its scaffolds one by one as they become infected. If you have trees with gumosis, prune them in late spring as the wounds can heal faster and not be as likely to pick up more infection from a blowing rain storm, etc. Disinfect the shears after each cut with bleach or vinegar so as not to spread the disease through the shears. If there is dead wood on the trunk and the tree is a young tree, you can cut out the dead wood and seal with Tanglefoot (http://www.tanglefoot.com/products/treeprune.htm).

If it is bacterial canker, use the same techniques as gumosis, but also spray with copper-containing compounds for control. Spray just before bud swell as copper can injure stone fruit crops and do not use more than one application.

If there is leucostoma canker present with the gum, then get on your knees and pray!

How do I know all of this? Been there, done that! With over 1,000 peach trees and 100 apricot trees as well as plum and aprium, we have experienced it all.
Hope this may help someone.

Dennis Norton
Royal Oak Farm Orchard
http://www.royaloakfarmorchard.com
----- Original Message ----- From: "tanis cuff" <tanistanis@hotmail.com>
To: <nafex@lists.ibiblio.org>
Sent: Thursday, April 06, 2006 2:13 PM
Subject: Re: [NAFEX] lime sulfur(apricot tree rescue)


Arboriculture answer, rather than an apricot-grower's: this probably won't save your tree. It is too difficult to remove all the infection, maybe impossible. And you will do lots of physical damage to the tree.

But if you are sure to lose the tree w/o intervention, then why not? To call it a comprehensive research project, take pieces of the infected bark & wood to a disease-testing lab. First get info from them on the best way to do this. Then you can say "Tree had these infections, and I did these procedures, and tree recovered/ died." Let us know.


----Original Message Follows----
From: mauch1
Reply-To: North American Fruit Explorers <>
To: nafex@
Subject: [NAFEX] lime sulfur
Date: Thu, 06 Apr 2006 15:02:45 -0400

I have a similar problem with an apricot tree. The tree is about 4-5 inches in diamter, and the visible fungi has spread to about half the trunk diameter and extends from the ground into where the tree begins branching.

Observation. I too have the white fungi, though mine looks more like shelf fungi. I believe they only came after the bark/tissue was already dead. I believe the problem started when the tree received winter damage from cracking bark (warm sun followed by freezing temperatures). The bark began to ooze. I call this 'gummosis', but I believe this was only a symptom not the cause. Possibly a bacterial infection?

What I'm planning to do. I kept expecting the tree to die, but its been going on for 3 years like this, with the dead area gradually widening. I think the healthy remaining tissue cannot recover as the moist/dead tissue is continuing to infect the healthy tissue, and the dead tissue blocks the regrowth. So unless someone has a convincing anti-argument, I'm going to remove the diseased dead tissue/bark with a chisel.

This should allow the wood underneath to dry out and not remain a source of fungi. The healthy tissue (theoretically), should be able to grow back over. Thoughts are welcome.

Chris Mauchline
SE PA, zone 6
40° 5' N 75° 51'W
~650 ft elevation









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