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 Trees Questions

Why is my Ash drooping?
June 22, 2009 - Last spring, I bought a house in Austin, TX with a large Ash tree in the front yard. It looked fine last year, but has been looking funny since it leafed out this spring. It's as if the leaves are we...
view the full question and answer

Mexican Plum not doing well in Liberty Hill, TX.
September 03, 2010 - Two summers have passed since I planted my Mexican Plum. It's in full sun. It seems to have added height but not much width. It's virtually a 7 foot stick with 1 foot branches from top to bottom. It...
view the full question and answer

Need a native tree for full sun in Hockley, TX
October 27, 2009 - What native trees should I plant for full sun. I am building on a 1/2 acre previously used as grazing land on the original Katy prairie. I need one large shade tree, a few smaller ornamentals, and a...
view the full question and answer

Oak Sucker Reprise
May 02, 2015 - ----Original Question---- SUNDAY - JULY 06, 2014 Title: Live Oak Suckers Reprise, Austin TX QUESTION: Referring to an entry dated March 11, 2011 about Live Oak suckers - what happened to the su...
view the full question and answer

Problem with baldcypress tree
May 27, 2011 - Two of my three 20 year old Bald Cypress trees appear to have leafed out but are now brown in parts of the tree. The brown area is at the tops of the trees which are probably 40 ft. high. They were...
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