En EspaŅol
Share

Ask Mr. Smarty Plants

Mr. Smarty Plants - Red-backed bugs on mountain laurel (Sophoro secundiflora)

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

Tilling for grass under old live oak in San Antonio
April 15, 2012 - Hi, I have a 250+ year old Texas Live Oak. As usual, the lawn under the tree, after 18 years needs to be redone. MY QUESTION: to put down new sod the lawn company needs to till the soil about 4 t...
view the full question and answer

Fasciation on Texas Mountain Laurel
November 21, 2012 - Do Texas Mountain Laurel normally have a staghorn looking growth hanging on them after blooming in addition to the seed pod clusters or could this be a mutation?
view the full question and answer

Need help diagnosing a problem with Bur Oak in Plano, TX
April 28, 2010 - I planted a bur oak 8 or 9 years ago. It has grown beautifully until this year. When opening, the leaves are very small (a couple inches) and there are lots of seeds (catkins?). I would hate to los...
view the full question and answer

Bacterial spot in peach tree in McDade TX
February 05, 2009 - I have a Red Globe peach tree which was planted in February 2008. The local agricultural extension agent identified the tree as having Bacterial Spot in November 2008. They recommended copper hydrox...
view the full question and answer

Sooty mold on Sophora secundiflora in San Marcos, TX.
September 23, 2010 - Dear Mr. SP, We have a Sophora secundiflora that is suffering with very black mold or fungus on most of its leaves. Last year, I washed it leaf-by-leaf with soapy water but it's getting too big t...
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