Thousand Canker Disease

Old Monkey

Treehouser
Joined
Mar 9, 2005
Messages
8,764
We just finished our annual Horticultural Expo here in Boise. There were some interesting lectures and some that made me envy my old boss who was snoring two seats away from me. One that was quite interesting and a bit depressing was by Professor Whitney Cranshaw from Colorado State University. He talked about boring insects in our region. He has been working on something called Thousand Canker Disease which is killing all of our black walnuts out West. Its really a two organism attack. Small walnut twig borers are carrying a fungus called Geosmithia morbida that infects and kills the tissue around the borer. The fungus doesn't spread too far but their are so many of the borers that the end result is a girdling of the tree.

These borers and the fungus started out in the Southwest, New Mexico, Arizona and Mexico. There they have a minimal effect of the native walnuts. Somehow they spread north and the effect on black walnuts has been devastating.

Now they have been found in Tennessee. That means they have a toe hold in the native, Eastern black walnut stands. Professor Cranshaw feels that that it may take decades but that all the black walnuts are goners. He highly recommends that we do not move black walnut around as two firewood pieces could contain thousands of these very small beetles. The symptoms are flagging, the die back of top branches. If you see this, he feels that it is already too late and the tree will be dead in under three years. Chemical treatments are not proving effective at this point.

http://www.thousandcankerdisease.com/
 
  • Thread Starter Thread Starter
  • #3
His ability to shamelessly sleep through a boring lecture.
 
i know it's not the same
but i've seen more european canker in apples this year
so many that the branches are mostly girdled
it's not practical to cut out all the cankers as there wouldnt be much tree left

and cleaning out each spot, and filling with gray pruning paint mixed with powdered copper would take hours per tree

anyone else noticed an increase in these?
Darin thanks for the info, nice to know about new diseases
 
'Tis nasty. Thousand cankers has started showing up in Canon city. The technical term for it is "job security".
 
  • Thread Starter Thread Starter
  • #7
Professor Cranshaw is a great speaker. Have you ever met him Justin? At 8 in the morning he made aphids seem really interesting, a super human feat if there was one.
 
  • Thread Starter Thread Starter
  • #9
Its a big hall. Wade also sneaks into class in the last five minutes and signs in on the CEU sheets too. The lecture he slept through was on professionalism.
 
i fell asleep when susan sims was doing a presentation on insects,
jeez several hours of glass cased bugs, after a work day just killed me
i felt like ben stein was giving the lecture
 
EAB from the East, Thousand Canker from the West, I'm in the middle. Think I will stay here for a while and see what happens when they both hit Iowa!
 
  • Thread Starter Thread Starter
  • #16
The fellow who talked to us thought that thousand canker disease is fast moving in terms of infecting trees but slow in killing them. A tree may be infected and live for even as much as ten years. Its just that when it show itself in dead tops, there is nothing that can be done.
 
Back
Top