Native Plants

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.
Did you know you can access the Native Plant Information Network with your web-enabled smartphone?
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.

rate this answer

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 Pennsylvania. Here 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
Tiny holes oozing sap from Austin
August 22, 2012 - My ash tree becomes loaded with butterflies on the trunk. At closer inspection, I see they are drinking sap which is coming from small holes in the trunk. Are the butterflies creating the holes? I ...
view the full question and answer
Swarming insects on non-native willow in Washington PA
September 25, 2011 - I have had a very large, beautiful pillow willow bush/tree growing next to our garage for about 8 years. Last year at the end of August, it began to attract white-faced hornets and yellow jackets by t...
view the full question and answer
Sticky film on oak tree leaves from Whitney TX
September 04, 2012 - What is the sticky film that is coating leaves on our oak trees?
view the full question and answer
Problems with non-native yellow lantana from Elgin TX
June 17, 2012 - Why do my yellow lantana buds turn brown and do not open fully? The sprinkler system does not spray onto the lantana.
view the full question and answer
Flying insects eating leaves of non-native Brugmansia in Aline CA
October 17, 2013 - I have an Angel Trumpet tree. We live in Aline, California
30 miles east of San Diego. Little yellow and black flying
bugs eat the leaves. Do you have a remedy for this problem.
view the full question and answer
Support the Wildflower Center by Donating Online or Becoming a Member today. |