En EspaŅol

Q. Who is Mr. Smarty Plants?

A: There are those who suspect Wildflower Center volunteers are the culpable and capable culprits. Yet, others think staff members play some, albeit small, role. You can torture us with your plant questions, but we will never reveal the Green Guru's secret identity.

Help us grow by giving to the Plant Database Fund or by becoming a member

Did you know you can access the Native Plant Information Network with your web-enabled smartphone?

Share

Ask Mr. Smarty Plants

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
1 rating

Wednesday - September 21, 2011

From: Abilene, TX
Region: Southwest
Topic: Diseases and Disorders, Trees
Title: Live oak trees with rusty spots and holes on tree trunks
Answered by: Nan Hampton

QUESTION:

I have live oak trees that have developed rusty spots, small holes on the tree trunks and sawdust on the trees base. They were planted in Oct 2010. We have had a hot dry summer in Texas this year and I am not sure if this is due to the extreme hot weather. Please advise.

ANSWER:

The principal disease associated with Quercus fusiformis (Escarpment live oak) is oak wilt.   As you can read on the species page on our Native Plant Database:

"...it is susceptible to live oak wilt and live oak decline when stressed by drought, so care must be taken to protect it from injury both aboveground and below ground to prevent infection."

Certainly, your trees have experienced the stress of extreme drought and high temperatures. I don't know if your trees are infected by oak wilt, but it is certainly possible.  You can see on this map from the Texas Oak Wilt webpage that Taylor County has been confirmed as having oak wilt.  You can see the characteristic leaf browning pattern associated with Texas oak wilt on the Texas Oak Wilt Information Partnership page. Contact the Taylor County Office of the Texas AgriLife Extension Service to see if you can arrange to have someone look at your trees to determine if you do have oak wilt.  You could also consult a professional arborist.  You can search for a Certified Arborist in Abilene on the International Society of Arboriculture page. The Texas Oak Wilt Information Partnership page has a wealth of information about diagnosing, treating and preventing oak wilt.

Another disease that can affect oak leaves is Tubakia (formerly known as Actinopelte) but it is usually a disease associated with wet years which certainly doesn't apply to this year.  For insect pests, you can read Insect Pests of Central Texas Forests to learn that nitidulid beetles are responsible for spreading the fungus, Ceratocystis fagacearum, that causes oak wilt and that stressed trees are often attacked by wood borer insects and oak bark beetles. 

Whatever you trees are suffering from, there is no doubt that they have been seriously stressed by the heat and drought conditions.  You might also read "Continuing Severe Drought Conditions Will Seriously Harm Trees" from the Texas Forest Service.

 

More Diseases and Disorders Questions

Central branches on Texas Ash have died
June 09, 2015 - I have a Texas Ash tree that was planted about 4 years ago. It seemed fine last summer and was well watered. This spring, when it started leafing out, the central branches at the upper part of the tre...
view the full question and answer

Insects attacking Gregg's Blue Mistflower from Comfort TX
June 20, 2013 - I have a beautiful stand of Gregg's Blue Mist flower that have been attacked by an unknown insect. The new growth is curled and stunted and it is not flowering. I'm not alone..I've seen the Gregg'...
view the full question and answer

Red spider mites in native bluebonnets in Austin
April 02, 2008 - What would you do if the WFC bluebonnets developed a bad case of red spider mites? That is what has happened to many of mine here in Austin. I noticed them the other day and I must have been asleep be...
view the full question and answer

Why is my Ash drooping?
June 22, 2009 - Last spring, I bought a house in Austin, TX with a large Ash tree in the front yard. It looked fine last year, but has been looking funny since it leafed out this spring. It's as if the leaves are we...
view the full question and answer

Mildew and rot in navel orange tree in California
September 02, 2008 - I have a great navel orange tree that seems to have two problems. One of them looks like powdery mildew and the other is some kind of black rot. I have sprayed it several times to no avail. I live ...
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.
E-NEWSLETTER | BECOME A MEMBER | DONATE NOW | MEDIA | SITEMAP | STAFF
© 2016 Lady Bird Johnson Wildflower Center