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
Not Yet Rated

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 Trees Questions

When is the appropriate time to prune pecan trees in Hewitt?
September 07, 2008 - Labor Day Weekend my husband decided to trim all the low branches on a big pecan tree in our back yard which I thought should had been done at the first of the year, our temprature is in the mid 90's...
view the full question and answer

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

Replacement for maple tree lost in Hurricane Sandy from Hauppauge NY
March 17, 2013 - Lost a Maple street tree in Hurricane Sandy, was forty-eight years old. Town will not replace the tree. Must do it on my own. What would you suggest? Nothing that grows too tall.
view the full question and answer

Privacy Screening Plant for New York Narrow Site
April 20, 2013 - I need privacy screening on the side of my house in Mount Kisco, New York located 40 miles north of New York City. The area gets plenty of sun but is somewhat narrow. What evergreen bushes or trees ...
view the full question and answer

Bracket fungus on live oaks
October 04, 2007 - I live in Cedar Park and the house we just bought has 4 native live oaks growing in the front yard. On two of the live oaks there are bracket fungi growing at their base. Each tree just produced two n...
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