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

Watering oaks in Houston, TX.
June 07, 2011 - Our yard (Real County, TX.) has many oak trees. We never water these trees, but I wonder if you recommend watering during this extreme drought. The trees look very stressed and are covered in ball m...
view the full question and answer

Oak diseases as a result of wet, cool weather
July 25, 2007 - The mature live oak trees in our back yard have been dropping leaves just like they do in March, but this is July! Small to medium spots on the leaves turn brown before they drop. The veins of the l...
view the full question and answer

Problem with American Beautyberry in Houston.
July 02, 2014 - My American Beautyberry is dying one branch at a time. The entire plant looks great, now flowering and starting to put out berries. Then one or two branches will completely die. Trim those off, wi...
view the full question and answer

Leaves turning yellow on Banana Shrub in Eutaw. AL
July 28, 2013 - We have a very large (about 12' tall), very old (probably planted in the early 1900s) Banana Shrub in our front yard. It was very healthy until last year when its leaves began turning yellow and fal...
view the full question and answer

Non-blooming Tecoma stans in Fredericksburg, TX
June 30, 2008 - We have an esperanza plant purchased last year from Walmart and planted outside before winter. It flowered excellently last year. Just before winter we cut it back to about a foot. So far this summer ...
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