Host an Event Volunteer Join Tickets

Support the plant database you love!

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

Please forgive us, but Mr. Smarty Plants has been overwhelmed by a flood of mail and must take a break for awhile to catch up. We hope to be accepting new questions again soon. Thank you!

Need help with plant identification, visit the plant identification page.

 
rate this answer
Not Yet Rated

Tuesday - November 03, 2009

From: Austin, TX
Region: Southwest
Topic: Trees
Title: Are the moths in my Austin, TX live oaks harmful?
Answered by: Joe Marcus

QUESTION:

It is November and my live oak trees are full of moths. What are they and are they harmful to my trees?

ANSWER:

The insects you're seeing is almost certainly not moths, but butterflies.  Texas is currently experiencing an explosion in the population of American Snout butterflies, Libytheana carinenta.  These population explosions regularly occur when certain climatic conditions are met.  During these times, billions of adult American Snout butterflies - which do resemble moths - may take to the air in Texas.  Other states may see similar flights of this species, but in much smaller numbers.

The good news is that American Snouts do not feed on Live Oak, only hackberry.  In fact, while the caterpillars of this species can, when the leaves are just emerging, feed on the foliage of any hackberry species, they actually feed almost exclusively on Celtis ehrenbergiana (spiny hackberry), listed as Celtis pallida by some sources.  For more on the interesting life history of this butterfly species, see this excellent article on American Snout "migrations."

The adult American Snouts visiting your live oaks are probably attracted to the nectar-like secretions of plant-sucking insects, like aphids, living on your oaks.  Though aphids and other insects like them do take some food and energy from Live Oak trees, they rarely cause enough damage to be of any real concern.  For more information on oak pests, please visit this webpage from the Forest Pests website.

 

More Trees Questions

Need help with my 25 yr old Mountain Ash in Clinton Township, MI.
July 11, 2011 - For the first time our 25yr old mountain ash tree has dying branches, we removed one branch and it seems to have spread to other branches? What should we do?
view the full question and answer

Native plants for shade in Ennis TX
August 26, 2011 - My house faces south. The southwest side of the front yard has a Pride of Houston, Japanese Barberry, 2 crape myrtles and some dwarf yaupon hollies. The other section, divided by a stairway to the p...
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

Bur oak defoliation
September 05, 2008 - I have a bur oak that was planted in 1993. In 2000, I had mortared stone edging (approx 5 inches deep) installed around the trunk from 4 to 6 feet away. In the last 3 years, the tree seems to be decli...
view the full question and answer

Fruit-bearing crabapple for Austin, TX
January 07, 2007 - Is there a fruitbearing crabapple that will live in Austin. If so, what soil type is required?
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.