Greetings,
 
I had what sounds to be the exact same problem a number of years ago
with Northern Spy on M-26. The most vigorous trees were the most
seriously affected. We had a heavy crop the year before and a long wet
fall. The tops had long sunken, purplish lesions, and they died from the
tops down. The bottom foot above the union was still good in most cases.
Some tree I pulled out and the rest I cut off below the lowest lesion.
Within three years I had the trees back almost as large as they were. I
shouldn't have pulled the others in hindsight.  It affected about
fifteen to twenty percent of the trees in the block.
 
We had some isolates taken, and as I recall it was identified as an
aerial version of Phytophora. No one locally had heard tell of this
organism causing symptoms above the crown. This block was on well
drained, gravelly loam soil, so there was no water ponding or imperfect
drainage.
 
The only good news is that the trees recovered and it hasn't been back
since in that block, although I do see it occasionally in other blocks
of different varieties and rootstocks. I saw some on Idared on MM-111
that were at least 25 years old recently.
 
Mark, I am sure I still have some pictures that I could send you for
comparison if you like.
 
Regards,
 
Larry Lutz
Nova Scotia
 

  _____  

From: evan...@benzie.com [mailto:evan...@benzie.com] 
Sent: April 8, 2010 9:42 PM
To: apple-crop@virtualorchard.net
Subject: Apple-Crop: sickness in the Pioneer Mac block



Hello all,

 

In 08 a neighbor with a 5 yr old Pioneer Mac block on G30 saw extensive
amounts of die-back in his trees, starting with trees hanging onto their
leaves going into late fall.  Spring of 09 showed that the most vigorous
trees were affected to the greatest degree with whole limbs, leaders and
some entire trees dying.

 

Everything looked good in the spring of 09 in our orchard, which is 7 yr
old P-Mac on M26.  We wondered if our neighbor had a problem because of
G30.  Many "experts" looked at his trees and the consensus was "winter
injury".  In early October we harvested our block and noticed nothing of
concern (except scab).  In mid-November we saw trees throughout the
block with dark leaves that refused to fall.  The most vigorous trees
seem to be the most affected.  Whole limbs seem to die from the tip to
or near the truck.  Leaders often turned dark brown down to just above
the lower scaffold limbs.  Trunks below this point are mostly
unaffected.  Most trees seem to be O.K. at this point in time but nearly
20% of the block has some degree of this malady.

 

None of our other varieties have this problem.

 

Does anyone have experience with this sort of situation?  Any ideas
would be appreciated.

 

Mark Evans,

Northwest Michigan



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