Native Plants

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.
Did you know you can access the Native Plant Information Network with your web-enabled smartphone?
Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.

rate this answer

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
A year and a half old live oak tree is doing poorly in Nevada, TX.
May 08, 2012 - We planted a live oak tree about a year and a half ago. the tree is still rather small. The leaves are of a vibrant green, however the leave have only grown through the center of the tree and not out...
view the full question and answer
Problems with volunteer tree in Joshua TX
February 15, 2012 - I have a 'volunteer' tree which has been in our back yard for about 15 years. It has had the usual traumas, ie. lots of snow, ice, etc. but after last years drought, its bark is coming off and sev...
view the full question and answer
Overwatering and fertilization of whiteleaf manzanita
July 27, 2007 - Hi, I have an Arctostaphylos Dr. Hurd, southern California coast, several years old, 10 feet, that has a few large branches with yellowing and spotted leaves... also dropping many.
causes? remedy? sh...
view the full question and answer
Ring of small holes around pecan tree branches
May 05, 2009 - I live outside Cooper, TX and I have a pecan tree about 15 years old, which I just noticed has little round holes (about the size of a pencil) going around the branches. It branches out about 3 feet ...
view the full question and answer
Iris Changing Color?
April 03, 2015 - I have some iris planted under a very tall tree and they bloom nicely every February. The original bulbs were given to me when I moved here to Arizona 30 years ago. They have always bloomed white. I h...
view the full question and answer
Support the Wildflower Center by Donating Online or Becoming a Member today. |