Steve,
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
----- Original Message -----
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?
Steve
dmnorton@royaloakfarmorchard.com
wrote:
Steve,
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
http://www.royaloakfarmorchard.com
http://www.theorchardkeeper.blogspot.com
http://www.revivalhymn.com
----- Original Message -----
From: "Steve" <sdw12986@aol.com>
To: "North American Fruit Explorers" <nafex@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:
http://im1.shutterfly.com/procserv/47b8da06b3127cceb7bd25dee78f00000025103AaNmrJi4Ze
(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:
http://im1.shutterfly.com/procserv/47b8da06b3127cceb7bd25db66ba00000026103AaNmrJi4Ze
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:
http://im1.shutterfly.com/procserv/47b8df24b3127cceb36cc2fe5ae800000036103AaNmrJi4Ze
As you can see, 80 or 90% of the leaves have fallen on this branch.
This branch was grafted over to Connel Red:
http://im1.shutterfly.com/procserv/47b8df24b3127cceb36cc2e3dbc500000036103AaNmrJi4Ze
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:
http://im1.shutterfly.com/procserv/47b8df24b3127cceb36cc2efdbc900000036103AaNmrJi4Ze
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:
http://im1.shutterfly.com/procserv/47b8df24b3127cceb36cc2d7dbf100000035103AaNmrJi4Ze
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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