En Español

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
2 ratings

Thursday - May 08, 2008

From: Austin, TX
Region: Southwest
Topic: Non-Natives
Title: Leaf-cutter ants on non-native crape myrtle
Answered by: Barbara Medford

QUESTION:

We have a problem with cutter ants. I lose my entire Crepe Myrtle tree every year. All of the pest control personnel I ask do not have a solution. Can you please suggest something to eradicate these pests?

ANSWER:

When we first started researching this matter, we found that most sites on crape myrtle mention only mildew and aphids as major problems. So then we went looking for leaf cutter ants, and found that it is an enormous problem. Like fire ants, these creatures are imported from Central and South America and have no natural enemies in our area. This very comprehensive site from Texas A&M AgriLIFE Extension, Leaf Cutting Ants, has a lot of information that you should read. The pest control people you have been talking to probably either don't know how to approach the problem or realize it is bigger than they can easily control.

To quote from the above site:

"Defoliation by leaf cutting ants can resemble damage produced by several other leaf chewing insects, particularly sawflies and leaf cutting bees. Trees defoliated by the leaf cutting ant usually are within sight of an ant nest and the ants themselves may be seen carrying leaves. Foraging trails will be littered with pieces of leaf tissue that can be traced to a feeder hole. Considerable damage to a plant can occur in a few hours. Small- to medium-sized trees can be stripped in one night. One researcher in South America estimated that a large leaf cutting ant colony harvested approximately 13,000 pounds of leaves over a 6-year period. This same colony excavated 802 cubic feet of soil weighing over 44 tons."

First of all, let's make sure we're talking the right bug. Take a look at this page of Images of leaf cutting ants and see if that is what is going on in your yard.

We checked some websites on leaf-cutting bees, and don't believe this is your problem. This Wikipedia article on Megachilidae-Leaf Cutting Bees says that the bees are mostly solitary bees, and only cut the leaves for material with which to line their nests. They are considered excellent honey bees and not pests to be gotten rid of. And they're certainly not the bugs that are stripping your crape myrtle.

Next, we checked out sawflies, and found another Texas A&M site, Sawflies, which told us they are not flies, but related to wasps and bees, very plant specific in the type of plant they attack, and seem more inclined toward conifers.

So, we'll assume that it is indeed leaf cutters that are after your crape myrtle. The most recent information I found on those ants was that they were threatening pine forests as near as East Texas and on east into Georgia and Florida. They apparently choose one particular plant to chow down on, but the reason they take so many leaves is not for food and not for nest lining but for their own version of farming. They go back to the colony, chew the leaves and spit them out and on this base a fungus grows which is the only food of the ants, including the young. When a queen ant flies, she takes a "starter" from this fungus, establishes a new little hole, and plants her garden. Then, the workers come in and begin the fresh tunneling. Because they eat nothing but the fungi, putting out bait is not successful. Because they have such a large and intricate colony of underground tunnels, spraying down the holes in the conical mounds doesn't go far enough to do any real good.

So, you and probably neighbors have a major problem. We're assuming you live in a part of Austin that is in Travis County. Go to this website for the Travis County Extension Office, find a contact number and ask them if this problem is known elsewhere in the area, and what they recommend you do. We would recommend you find a licensed professional who will make whatever applications are necessary. We're afraid that cutting down the crape myrtles will not be any help, because the ants might just choose another host plant. In the meantime, you could always use the old home remedy of scattering diatomaceous earth (DE) on the mounds and the routes the ants are taking. It won't eliminate them, but it will give you some feeling of revenge, because the DE scratches their external protective covering, drying it out and killing them.

 

 

More Non-Natives Questions

Problems with non-native mimosa
August 29, 2008 - We have 2 large mimosa trees in front of our house that are close to 50 years old. They have not been cared for over the past 8 years (we did not live here). This year, I trimmed them, removed dead ...
view the full question and answer

Removal of invasive non-native Chinese wisteria
September 10, 2007 - I am going to be removing my ubiquitous chinese wisteria very soon (the method I'm going to use is undetermined). If I decide to use Round-up on the cut-stem (which may take more than one application...
view the full question and answer

Rose care for Austin
August 18, 2013 - I am a transplant from the Pacific NW and need to relearn rose care for Austin. When is the best time to cut back the roses, or do I even bother? I also need to find out how far back I can trimming a...
view the full question and answer

Cultivation of non=native Brugmansia sanquinea
January 04, 2006 - I have had an Angel Trumpet since spring 2004, I keep it indoors in about 5 hours of sun a day. It is about 5 feet tall and was loaded with leaves. At Christmas time I had to move it from the front wi...
view the full question and answer

Non-native lilacs for Salt Lake City, UT
April 15, 2012 - Is the weather in Salt Lake City UT good enough to plant a lilac bush root? If not, how long should I wait?
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.
E-NEWSLETTER | BECOME A MEMBER | DONATE NOW | MEDIA | JOBS | SITEMAP | STAFF INTRANET
© 2016 Lady Bird Johnson Wildflower Center