Rent Shop Volunteer Join

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
4 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

Esperanza freezing back in Highlands, TX
April 16, 2011 - I have an 3 yr. old Esperanza that froze the last two yrs. but grew back each spring. This spring after getting about 2 ft. the leaves at the bottom began turning brown at the edges and now seems to...
view the full question and answer

Potted Plumbago, struggling with the heat, in Spring Texas
June 29, 2011 - Why do some of the leaves of my plumbagos that are grown in large, well-draining planters turn brown? The brown starts on the tips, then extends to the whole leaf. They get several hours of west aft...
view the full question and answer

Something killing evergreens on Long Island from Baldwin NY
June 06, 2011 - What seems to be killing so many of the evergreens on Long Island - see more and more dying each day - doesn't seem to be a rhyme or reason - can it be helped? Many thanks.
view the full question and answer

White mold on Bermuda grass
August 07, 2012 - I tried searching and could not find info for this on your website. What causes mold in Bermuda grass and how can I get rid of it? Tried fungicide as recommended by garden center in austin which did...
view the full question and answer

Possible causes for plant problems in East Texas
September 06, 2007 - I have been an avid gardener for over 35 years in Texas.I love the wildflowers and use them extensively in my 2 acre plot here in East Texas. There is something really bad going on with my garden: pl...
view the full question and answer

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