[NAFEX] Trouble in paradise? (apple tree)

dmnorton at royaloakfarmorchard.com dmnorton at royaloakfarmorchard.com
Tue Apr 29 14:57:27 EDT 2008


Borers will typically only feed on the bark layers, but can bore into the hard wood.  I've seen them completely girdle a 6" trunk and eat down to 1" left on the trunk.  The only spray that really knocks them out is Lorsban.  Lorsban is a restricted use pesticide, so I'm not sure if you can purchase it without certification.  The borer eggs are usually laid in May and hatch in June.  An option for you to consider would be one of the Ortho products with Malathion or Sevin at a higher rate.  Check your Sevin label for the proper rate.  Mix enough to do a trunk spray each week for 6 to 8 weeks.  You want to make sure you get the larvae.  If you do spot eggs, cover them in hort oil and it will smother them.  I am attaching a fact sheet for you.  Hope this helps!
Dennis Norton

Royal Oak Farm Orchard
  ----- Original Message ----- 
  From: Steve 
  To: dmnorton at royaloakfarmorchard.com ; North American Fruit Explorers 
  Sent: Monday, April 28, 2008 9:52 PM
  Subject: Re: [NAFEX] Trouble in paradise? (apple tree)

  Yeah, that does help.
  I went back to my original large image and I see what you mean. It doesn't take any imagination at all to see old tunnels along that left side. I don't know if that's what we're really seeing, or not. This only leads to more questions:

  Do apple borers drill into the wood or only travel along between the hard wood and the bark? I found no tunnels into the wood. I poked around with the point of the knife and found nothing breaking the solid wood surface.
  If I do a trunk spray, what do I spray on the trunk? I've never suspected borers before so I've never looked into preventing the problem. I usually do 2 Imidan sprays after petal fall, sometimes 3 depending on the weather. Then, later I do 2 sprays of Sevin when I catch some apple maggot flies. If I spray the trunk too, will that help with borers?  Do I need some other product? How early or late in the season do they attack?


  dmnorton at royaloakfarmorchard.com wrote: 

I blew up your image and enhanced it and it sure looks like borer canals 
running up and down the left side of the damaged area to me.  I might be 
wrong, but I would still suspect borers caused the problem.  Once they bore 
through the bark and begin entering the live tissue of the tree, that part 
of the tree no longer takes up nutrients to the remainder of the tree.  The 
leaves on that side of the tree will yellow and some die off due to lack of 
nutrients.  In the spring, there isn't enough tissue to be fed yet, so 
everything seems to be coming out.  Once the amount of tissue has been 
produced that is greater than the nutrients being taken up, the leaves will 
yellow and die off as you describe in your last paragraph.  I hope you are 
right and it is not borers, but a trunk spray to protect the area won't hurt 
and you could  also wrap the area with tree wrap to prevent borers from 
attacking the area.  If they are not the culprit, you don't want to give 
them any ideas!  Hope this helps!

Dennis Norton
Royal Oak Farm Orchard
----- Original Message ----- 
From: "Steve" <sdw12986 at aol.com>
To: "North American Fruit Explorers" <nafex at lists.ibiblio.org>
Sent: Sunday, April 27, 2008 12:13 PM
Subject: Re: [NAFEX] Trouble in paradise? (apple tree)

  Replying to my own post (below) from 5 or 6 weeks ago. Back then, the 
ground was still deep in snow. Now it has all melted and the ground dried 
out enough for me to flop onto the ground and investigate the dead area on 
my apple trunk. The general consensus was that I probably had borers. Last 
weekend I flicked off the loose bark and used a sharp knife to find the 
live edges. I trimmed back the edges until I found live tissue. As you can 
see from this picture, there is no borer damage, just smooth wood with 
(now) no bark:
(See the pre-surgery picture below. It's the last link.)
I'm not surprised by this. I never believed I had borers.
I was a little afraid that it started as collar rot, and that made the 
dead area. I kind of doubt it now. The dead area does not quite go to the 
ground. I encountered live bark right at the soil line. Besides, there is 
good water drainage since the tree sits on the brink of a drop off so that 
right next to it, the ground goes 2 feet lower: 

If you remember (or read below), my original concern was the branches 
above the bark defect had all the leaves turn yellow and fall off several 
weeks before the healthy side of the tree lost leaves. I expected those 
branches to be dead this spring.
The BIG surprise is that those branches are waking up right along with all 
the other apple branches. It's still early here and the green tips are 
only a quarter inch long with the tips of the flower bud just visible 
inside. EVERYTHING looks normal right now. I'm not celebrating too much, 
because I have the memory of one of my first apple trees (before I knew to 
take care selecting hardy cultivars). That tree leafed out as normal one 
spring, then in June when the new shoots were 3 or 4 inches long, most of 
the branches just wilted and dried up. Apparently a victim of winter 
injury to the trunk.

Thanks for reading.

Steve in the Adirondacks

Steve wrote:
    When I first joined this group last year, I told that I had 4 apple 
trees, 3 of which I have grafted to multiple varieties. (I have other 
fruits; sticking to apples here.)

I'm afraid one of my multi graft trees is doomed. It has taken me a while 
to get around to asking the questions. I took these pictures last 
September on Labor Day Monday! The problem is that the branches on the 
north side of the tree had the leaves turn yellow and fall off early. 
About 3 branches were completely bare by the end of September, long 
before the first frost and long before any leaves were lost on other 
branches and other trees. Twice, over the last 20 years, I have had a 
whole tree (one cherry and one plum, I think) loose the leaves early and, 
of course, it was completely dead in the spring.

Here is a branch that was grafted over to Red Baron:
As you can see, 80 or 90% of the leaves have fallen on this branch.

This branch was grafted over to Connel Red:
This still has some green leaves but every day, more and more turned 
yellow and fell off.

Both of these branches and at least one other tried to produce apples but 
they were not edible. Around on the other side of the same tree, this 
Sweet Sixteen branch was all business as usual:

Last of all, here is a picture of the lower trunk. This is the north 
side, directly below the bad branches. I certainly assume this is the 
source of the problem:
After the picture, I did a little poking around and I believe the bark is 
alive right at the soil line and below. There seems to be a dead zone 
where it looks bad in the picture. Don't suggest that it is lawnmower 
damage. I'm the only one who mows the area and I DO NOT touch the trees 
with the mower. I'm thinking it is simply some disease which is very bad 
news for this tree. I'm expecting the affected branches to be dead this 
spring. I will not know for sure until at least 2 more months. So what 
happened here? Is there anything I can try, to salvage the remaining part 
of the tree?

Steve in the Adirondacks (zone 4 on the map, zone 3 in real life).

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