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

Friday - October 19, 2012

From: Houston, TX
Region: Southwest
Topic: Pests, Trees
Title: Are fuzzy oak leaf galls harmful to post oak trees?
Answered by: Nan Hampton

QUESTION:

Are the fuzzy balls on the undersides of our post oak trees harmful?

ANSWER:

The fuzzy balls are galls formed by the tree leaf in response to the feeding of the larvae hatched from an egg deposited by a tiny gall wasp in the Family Cynipidae, Genus Andricus.  Here are photos of Andricus quercusflocci galls that form on leaves of Quercus alba (white oak) and Quercus prinus (chestnut oak).  Andricus pattoni is reported to be the species that lays eggs on postoaks, but I could find no photos for that species of gall wasp.  Here is a link to an article about other Oak Cynipid Galls from the Department of Entomology, University of Minnesota.  You can see other types of galls in this article from the University of Wisconsin-Milwaukee and here is more information and photos from the University of PennsylvaniaHere is a link to an article on Randy Lemmon's Gardenline on KTRH radio about galls on oak trees in Houston in 2010.

In general, the galls are not harmful to the trees and there is really no insecticide that is effective since the wasps are tiny and not easily seen, plus the larvae are well-protected from pesticides within the galls.  Additionally, insecticides applied are very likely to be harmful to beneficial insects.

 

More Pests Questions

Bugs eating new growth on Mountain Laurel shrubs from Dripping Springs TX
April 02, 2013 - What is eating the new growth on my mountain laurel shrubs? One plant has red bugs and the other has black (could they be love bugs?). Is there something I can do to preserve the new growth?
view the full question and answer

Worms in non-native snake plant from Hillsborough NC
September 17, 2011 - I purchased a snake plant this summer for my screened in porch. I did not repot it and left it in the plastic pot in came it. I was about to repot the plant to bring it in and noticed there are worm...
view the full question and answer

White fungus-like growths on plants from Stephenville TX
May 25, 2013 - What is a white fungus-like growth on plants in a garden? It can be seen on the ground in ball-like shapes similar to puff balls or on plants
view the full question and answer

Groundcover for vineyard from Round Rock, TX
February 04, 2013 - I will be planting a vineyard in the Hill Country next spring. I am looking to maintain low-growing understory plants across the entire vineyard to maintain soil health, choosing plants that the leaf...
view the full question and answer

Eliminating muskrats from a cottage garden in Ontario
August 22, 2010 - We have perennial gardens at our cottage and for the first time this year the muskrats have come and leveled everything..shasta daisies, coneflowers, day lilies, phlox, etc. Any suggestions as to how...
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 | STAFF
© 2015 Lady Bird Johnson Wildflower Center