En EspaŅol
Share

Ask Mr. Smarty Plants

Mr. Smarty Plants - Hypoxylon Canker removal in Austin TX

Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.

Search Smarty Plants
    
 
See a list of all Smarty Plants questions
Can't find the answer in our existing FAQs, submit a question to Mr. Smarty Plants.

Need help with plant identification, visit the plant identification page.
 
rate this answer
Not Yet Rated

Monday - March 26, 2012

From: Austin, TX
Region: Southwest
Topic: Diseases and Disorders, Trees
Title: Hypoxylon Canker removal in Austin TX
Answered by: Brigid & Larry Larson

QUESTION:

I have several oaks that appear to have been killed by Hypoxylon atropunctatum from last summer's drought. Is it safe to cut them down in March or does that risk spreading Oak Wilt too. Should I let them sit there dead until summer?

ANSWER:

Mr Smarty Plants offers his condolences on the loss of your Oaks.  That always hurts. 

Your question evoked considerable discussion amongst the experts at the Ladybird Johnson Willdflower Center.  It's clear the trees need to be removed, but there were good arguments for either "right now" or "wait until next winter". A general concensus clearly recommended that you employ the services of a Texas Oak Wilt Certified Arborist and get a expert diagnosis of the trees condition and recommendation for how to go on.

The argument for waiting is the one you implied. When considering Oak Wilt, it’s just a bit late to be cutting trees down.  The standing advice is to prune from December into early February. The risk you induce by waiting is that the Hypoxylon Canker that is there may infect other trees.  You can have hope that this year this risk is minimal as the references linked below imply that healthy, well watered trees are not all that susceptable to the canker. There is also a risk, in truly advanced cases, that the tree wood will be weaked by the fungus and drop limbs or fall.  

The argument for "cutting now" is that you do have Hypoxylon Canker there.  Leaving the trees stand until summer or later is leaving a viable source of the fungal infection in place. The Florida Forest Service describes the fungal growth process.  In the spring or early summer, masses of spores called conidia are produced on the surface.  Later in the summer or fall, after the powdery conidia are gone, the fungal stromata thicken and produce another type of spores. These are the infective ascospores which are present later in the summer or fall.    The Florida Forest Service recommends removal of the tree. 

 The Oklahoma State Extension recommended “In a home setting, individual trees that have more than 15% of the crown area infected should be cut to ground level and burned. No stump should be left because stroma development has been observed even on very small stumps.” The Texas Forest Service also has a publication describing the course of the infection, and there are  several publications from TAMU including a 3-part fact-sheet. This one addresses managing Hypoxylon canker.

It makes sense to remove trees that can serve as viable sources of continuing infection, but at the same time one should be concerned about Oak Wilt as that is a continuing concern for the other trees.  One should take extreme care that the neighboring Oak trees are not damaged by the removal and follow the expected precautions following the work. This includes tool cleaning, not storing infected wood on the property, and all pruning cuts or other wounds, including freshly-cut stumps and damaged surface roots, should be treated immediately with a wound or latex paint to prevent exposure to contaminated insect vectors. I will repeat the recommendation of consulting a certified Oak Wilt Arborist!

Mr Smarty Plants has produced several answers concerning Hypoxylon Canker, most of them involve determining that this is the source of illness.  There are several other good links in these answers though. 

 

More Diseases and Disorders Questions

Live oak leaves yellowing from Denton TX
January 26, 2012 - In autumn of 2010 I planted 10 live oaks about 6 to 7 ft. tall. I have see that during the month of Dec. 2011 to Jan. 2012 they are showing some yellow leaves. What can I do to help them?
view the full question and answer

Death of Texas Betony and Blackfoot Daisy from Austin
April 18, 2013 - I have one small area that there are two plants - Texas Betony and Blackfoot Daisy withered and died eventually. Same kinds of plants are doing fine close by. It is my front yard close to walk way.I w...
view the full question and answer

Problems with Juniperus scopulorum in Dallas
May 19, 2011 - Dallas, Texas - Juniperus Scopolorum "Skyrocket" Last June I planted six, five foot tall along my chain length fence by the alley. Full sun. One died within 6 months. The soil seems to stay damp...
view the full question and answer

Problems with non-native weeping willow
April 17, 2009 - The trunk of my Weeping Willow tree has raised donut growths.The left base has decay. There is a large space between the base and the soil (no roots) and the wood is brittle. Large ants with a black ...
view the full question and answer

Is December a good time to prune oaks in Central Texas?
December 29, 2010 - Given that we haven't had much cold weather here in central Texas (Wimberley) this season, is it a good time to trim live and Spanish oak trees (damaged limbs and low hanging branches and suckers)? ...
view the full question and answer

Smarty Plants's Facebook profile Support the Wildflower Center by Donating Online or Becoming a Member today.

Mr. Smarty Plants wants you to be his Facebook friend. Click the Facebook icon to add yourself to Mr. Smarty Plants list of friends.
E-NEWSLETTER | BECOME A MEMBER | DONATE NOW | MEDIA | SITEMAP
© 2014 Lady Bird Johnson Wildflower Center