Subject: Fire blight and malus x purpurea

From: Leslie Troutman <[email-masked]>
Date: Tue, 28 Mar 1995 13:05:08 -0600

Anyone have any experiece with crab apples and fire blight?  I'm
pretty sure that's the problem.  The tree is about 25'- 30' tall (tops for
this model, I think).  Last summer there was a poor blossom showing (but I
know that that's ok), it leafed out late and sparse, and the leaves
dropped early.  Several of the branches had the tell-tale brown, wilted
look at the ends; even worse, on side of trunk looks scorched and the bark
is peeling.  Can this tree be saved (organically)?  If it's got to come
down, should I stay away from other apple cultivars for a few years?  
Should I get someone who knows what's going on to looks at it?

Leslie 
[email-masked]

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From: [email-masked]
Date: 28 Mar 95 17:23:26 -0600

> Should I get someone who knows what's going on to looks at it?

Fireblight is a bacterial disease (most plant diseases are fungal or
viral).  It's very hard to control once it is established.

There is an amber ooze from the flowers when they bloom, and
later, the fruit spur will wilt and curve-- it will look like a
black cane.

Pruning all wood showing signs of blight will sometimes work;
remove at least 6 " of healthy wood below each cut.  Disinfect
all tools between cuts in 1 part chlorox to 9 parts water.  Dispose
of cuttings in bleach water and send them to the landfill in sealed
containers.

Streptomycin (yep, the antibiotic) sprayed during bloom time may be
effective.  In my experience, a tree with fireblight can be coddled
along, but it's basically a goner, and I'd sooner cut it when I
find it.

Before you do anything drastic, though, submit a sample of your tree
to a plant pathologist for diagnosis.

When you submit a sample, cut 6-12" long twigs from various
parts of the tree.  Get some healthy twigs, some that are apparently
beginning to show signs of a problem, some tha definitely show
the problem.

Bundle them up with a  single layer of paper towel around them, 
put them in a plastic bag, and mail it or take it to your cooperative
extension service or to your plant disease clinic at your state
ag school.  Include with it the following information:

Approximate age of the tree (if known)
Size (height and trunk diameter about 4 ft from the ground (=dbh))
When you first noticed the problem
How much of the tree is affected?  Is it on one side, or randomly
  all over?
Is the tree in sun or shade?  Is the affected part in sun or shade?
What kind of soil is the tree growing in? (sandy, clay, good garden
  soil; over a utility line.....)
What fertilizers or chemicals have you applied to the tree?
Any chance your neighbors have sprayed something that drifted onto
  your tree?
Are other trees in the area showing similar symptoms?

Oh yes... if you're going to mail your sample, do it early in the
week.  Samples mailed on Friday that sat around in a nice warm
postoffice all weekend, and didn't get opened until Tuesday because
of the Monday Mail Flood sometimes are so decomposed that you pour
them out of the bag..... makes diagnosis more difficult!

Kay Klier  [email-masked]

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From: [email-masked]
Date: 28 Mar 95 17:23:26 -0600