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

Identification of insects on crepe myrtle in Florida
May 22, 2013 - I have large colonies of striped bugs on large crepe myrtle in my backyard. They stay in large groups and have long antennae. There are larger black bugs among the groups that appear to corral and g...
view the full question and answer

Fungus Spots on Native Bush Honeysuckle
December 03, 2010 - My native bush honeysuckle plants that I have along my back fence have leaves that are turning yellow with spots. It appears to be a type of fungus, but not powdery mildew. Any suggestions as to what ...
view the full question and answer

Black Sap from Live Oak in Austin, Texas
April 20, 2015 - We live in South Austin and our neighbor has several beautiful, enormous Live Oak trees whose canopies hang over into our yard. This past week, they've begun dripping some sort of black sap all over ...
view the full question and answer

Problems with Shumard Oaks and Crepe Myrtle in Cooke Co. TX
September 07, 2013 - I have a Shumard Oak Tree that has been in the ground approx. ten years. It has done great, even passing up some of my older Shumards. In August it began to lose its leaves at an alarming rate. They a...
view the full question and answer

Mosquito repelling plants from Euless TX
July 24, 2013 - Are there any shade loving plants that repel mosquitoes for North Central Texas? I checked your site and saw nothing on this topic.
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