Host an Event Volunteer Join Tickets

Support the plant database you love!

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

Please forgive us, but Mr. Smarty Plants has been overwhelmed by a flood of mail and must take a break for awhile to catch up. We hope to be accepting new questions again soon. Thank you!

Need help with plant identification, visit the plant identification page.

 
rate this answer
Not Yet Rated

Wednesday - June 17, 2015

From: Austin, TX
Region: Southwest
Topic: Diseases and Disorders, Trees
Title: Red oak leaves have a swelling along the veins
Answered by: Guy Thompson

QUESTION:

I have red oaks in my back yard, approx 30 or more have a disease that are wilting the leaves. Looking at the back of the leaf there is swelling along the spines. I've gone to one nursery in town that confirmed it was not oak wilt, but had not seen this symptom before. I can send a picture on request. The trees all seem to be fully affected on all branches.

ANSWER:

The disorder of your Quercus texana (Nuttall oak) is caused by the action of a small midge with a name, Macrodiplosis quercusoruca, much longer than itself. It llays its eggs near the leaf vein.  Chemicals secreted by the midge's larva as it feeds by the leaf vein cause the tissues by the veins to swell.  It seems common in the Austin area this year.  I have noticed infested oaks in my yard for the first time.  Perhaps the midge prospered because of the unusually wet weather.  There is apparently no remedy for this infestation, but I believe that the trees will survive.

 

More Diseases and Disorders Questions

Tilling for grass under old live oak in San Antonio
April 15, 2012 - Hi, I have a 250+ year old Texas Live Oak. As usual, the lawn under the tree, after 18 years needs to be redone. MY QUESTION: to put down new sod the lawn company needs to till the soil about 4 t...
view the full question and answer

Problems with non-native Cleyera and Red-tip photinia
June 01, 2008 - I planted a row of Cleyera in a bed that receives sunlight for about 3 hours during the middle of the day. My problem is that a number of the plants are dying. It begins with the leaves on one small...
view the full question and answer

Diagnosis of problem with Parsley hawthorn
August 06, 2007 - I have a Crataegus marshallii (Parsley hawthorn) that is about 3 years old. It leafed out this spring and flowered lightly. As the summer has progressed, though, the leaves have been dropping premat...
view the full question and answer

Willow woes in Philadelphia, NY
August 22, 2010 - I have a 2 yr old willow; it is August and it looks like the tree has gone dormant, is this normal?
view the full question and answer

How to treat bark damage on oak tree
November 15, 2011 - I have an oak tree approx. 50 ft., live in austin, texas. the tree has dropped bark about 3-4 ft above ground, in a section of 4 inches by 8 inches, and the tree appears dark where the bark was. is ...
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.