Explore Plants

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
    
 

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

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

Location of Alamo fungicide kit from Georgetown TX
July 03, 2012 - Where can I buy the Alamo fungicide injection kit shown in the oak wilt video?
view the full question and answer

Dying trees in San Marcos, Texas
September 24, 2011 - I live on 11 acres in San Marcos and cannot water at all during this drought. All of my oaks and mountain laurels are turning brown. Does this mean they are all dying? Will they come back in the sp...
view the full question and answer

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

Mountain Laurels are dying in Georgetown, TX.
April 02, 2012 - Ten year old Mountain Laurels both last year and this spring have had entire branches turn brown just after blooming this Feb. Round Rock Arborist suggested I contact you. Last year one of my laurels...
view the full question and answer

Need help diagnosing a problem with Bur Oak in Plano, TX
April 28, 2010 - I planted a bur oak 8 or 9 years ago. It has grown beautifully until this year. When opening, the leaves are very small (a couple inches) and there are lots of seeds (catkins?). I would hate to los...
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.