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
2 ratings

Wednesday - May 12, 2010

From: Austin, TX
Region: Southwest
Topic: Diseases and Disorders
Title: Red-backed bugs on mountain laurel (Sophoro secundiflora)
Answered by: Nan Hampton

QUESTION:

I found red-backed bugs (in fact two end-to-end like the east Texas love bugs) on my mountain laurel which has been losing leaves. Are these bugs the culprit?

ANSWER:

Sophora secundiflora (Texas mountain-laurel), according to the US Forest Service "...are primarily pest-free, except for infestations by caterpillars of a moth in the family Pyralidae."  The moth is Uresiphita reversalis (Pyralid moth or Genista broom moth).  You would see the caterpillar and its damage from chewing on the leaves if they were infesting the plant.  Obviously the bugs aren't the caterpillars and since there don't seem to be any other serious insect pests I don't think the bugs are the culprit.  The Forest Service site does mention that the mountain laurels are especially susceptible to phenoxy herbicides.  One of the commonest of these phenoxy herbicides is 2,4-D.  These particular herbicides are used against broadleaf weeds on grass lawns, pastures or in grain fields.  The problem is that they are very volatile and can drift for miles with the wind and effect plants far from their application. They have been especially detrimental to grapevines.  If you or your neighbors have been using any of these on your lawns, it is possible that some has landed on your mountain laurel and is causing the problem. 

Another possibility is that you have had some environmental change where the plant is growing.  Mountain laurels like well-drained soil to grow in.  They don't like having 'wet feet'.  Has the drainage in its vicinity changed?  Is there the possibility that the soil has become compacted by a lot of traffic—foot or vehicle?  If you think that this has happened, you need to remedy this by stopping the traffic and adding a hardwood mulch over the soil surrounding the tree.  It will help protect the roots and eventually work its way into the soil and relieve the compaction. Better yet, you could carefully work some of the mulch into the soil so that when the tree does get water (from rain or supplemental watering) the water gets to the roots and doesn't stand on top of them.  Whatever you do, don't fertilize the tree. In the first place, native plants don't need fertilizing and a plant under stress (as yours seems to be) should never be fertilized.

 

More Diseases and Disorders 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

Growth in oak tree in San Antonio
April 05, 2011 - We have a very large gorgeous oak tree in our backyard here in San Antonio, Texas. I noticed a thickness high up in the tree. Thinking it was a nest of some sort, I used binoculars and saw a parasiti...
view the full question and answer

Strappy leaves on rudbeckias from Houston
October 31, 2013 - My Rudbeckias keep sending up odd shoots with strappy leaves on them. Should these be cut off? What is their purpose?
view the full question and answer

Yellow in pin oak leaves from Allen TX
May 25, 2012 - I have two pin oaks and one is completely yellow - a sign of iron deficiency and the other is starting to turn completely yellow as well. I've a proposal for iron deficiency but it is quite expensiv...
view the full question and answer

Sooty Mold on Beauty Berry
May 19, 2009 - We recently planted a beauty berry plant (among others) to attract birds in our backyard. We have had a lot of rain (probably 5-7 inches) since planting a few weeks ago if that might have something to...
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