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
Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.
rate this answer
Sunday - February 25, 2007
From: Austin, TX
Region: Southwest
Topic: Diseases and Disorders
Title: Control of sooty mold from aphids in Crape Myrtle
Answered by: Joe Marcus
QUESTION:
I have a crape myrtle in my front flower bed that has a sooty black substance on the leaves and trunk. I've done research and understand this is caused by aphids. My question is how do I get the black sooty substance off the tree and what do you recommend for getting rid of the aphids?ANSWER:
Sooty mold is a fungus, or more commonly a complex of two or more fungal species, that grows on honeydew or on plant exudates. Honeydew is a waste-product of aphids and other plant-sucking insects. As honeydew is excreted by sucking insects, it falls and coats any surface upon which it lands. Sooty mold fungi invade and live upon this sugary coating. These fungi do not infest the leaf ifself. Thus, sooty mold may often be found growing on any exposed surface beneath aphid-infested trees and shrubs. Sooty mold can cause great harm to plants, however, by blocking sunlight to the leaf surface below and diminishing photosynthesis.Sooty mold can often be successfully removed by rinsing with water from a garden hose. However, this will be most effective after the aphids or other honeydew-producing insects are destroyed. Sometimes sooty mold development is so severe and persistent that only time and exchange of leaves through the growing seasons will remove it all.
Aphids are not especially difficult to control and non-chemical methods are usually very effective. Insecticidal soaps are often the remedy of choice for many gardeners. Various brands of insecticidal soaps may be found at just about any retail nursery or garden center. Be sure to read and carefully follow all label directions when using any pesticide, organic or chemical.
More Diseases and Disorders Questions
Watering Houseplants with Soapy Water
August 22, 2011 - I accidentally watered my house plants with a container that had a some dishsoap in it. Will they be okay? One of the plants is a 20yr old cactus, with small roots.
view the full question and answer
Problems with a two year old persimmon tree in Fredricksburg, TX.
May 22, 2013 - Hi Mr/Ms Smarty Plants, We planted a 4-ft Texas Persimmon, Diospyros texana, 2-years ago, with wonderful leaf and fruit production since. We recently had a hail storm (5/9/13) and although mos...
view the full question and answer
More on oak problems in Carrollton TX
April 04, 2011 - Thank you for answering me, I will contact a specialist to see if we can determine the cause. but since writing you we have pulled down a small twig to see the leaf more closely, it is more of a reddi...
view the full question and answer
Problems with maple tree in Redding CA
July 17, 2012 - I have a 2 yr. old October Glory tree that is looking bad. It leafed out this spring, but not as much as the others. In total I have 9 red maples along a fence row about 15 feet apart. The trees on ei...
view the full question and answer
Cutting Back Perennials in the Fall?
November 13, 2013 - We have large beds of flowering native perennials that we planted around our house as part of a landscape conservation plan (various Joe-Pyes, goldenrods, turtlehead, blazing star, brown-eyed Susans)....
view the full question and answer
| Support the Wildflower Center by Donating Online or Becoming a Member today. |