North American Fruit Explorers mailing list at ibiblio

[<dmnorton@royaloakfarmorchard.com>]

Betsy,

Sometimes lesions on trees may not actually be fire blight but just a lesion 
where it overwinters.  The bacterium spends the winter in these sunken 
lesions (cankers) on the host tree. In the spring the bacteria ooze out of 
the lesion or canker and that is how it gets spread.  In the past, I have 
cut out these cankers on trunks by slicing the bark about 1 inch around the 
cankers and removing it to clean wood.  I spray the area of "surgery" with 
apple cider vinegar or a dilute mix of strep (Agri-Mycin) and seal it with 
grafting tape or a tree wrap to protect the open wound.  The next growing 
season I have had no blight reappear on the tree. I've done this on maybe 6 
or 8 trees.  If more than one tree is affected, be sure to disinfect the 
cutting tools between trees so as to not spread the overwintering bacterium. 
Hope this helps!


Dennis Norton
Royal Oak Farm Orchard
http://www.royaloakfarmorchard.com
http://www.theorchardkeeper.blogspot.com
http://www.revivalhymn.com
----- Original Message ----- 
From: <Hilborn.E@epamail.epa.gov>
To: "North American Fruit Explorers" <nafex@lists.ibiblio.org>
Sent: Friday, December 21, 2007 9:57 AM
Subject: [NAFEX] Fireblight lesions on trunk


> My 3- 4 inch diameter oblique cordon apples have now shed most of their
> leaves and I am viewing the sad results of last spring's fireblight
> attack.
>
> Despite my ongoing efforts to prune out affected wood all spring/summer,
> I am seeing obvious lesions on the trunk of a few trees (3 of 11).
> Luckily they are above the graft. Unfortunately, they are low on the
> cordon - about 6-10 inches above the grafts.
>
> All of the trees have a lateral branch below the lesions. Most are weak,
> only pencil thick or so.
>
> Am I better off pruning that thick trunk to just above these weak
> laterals and trying to re-establish a leader, or am I just delaying the
> inevitable and putting my other trees at risk?
>
> Thanks for any advice you can provide.
>
> Happy Holidays everyone!
>
> Betsy Hilborn
> 7 (still) but surrounded by zone 8, NC