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
Monday - April 20, 2015
From: Austin, TX
Region: Southwest
Topic: Pests, Trees
Title: Black Sap from Live Oak in Austin, Texas
Answered by: Anne Van Nest
QUESTION:
We live in South Austin and our neighbor has several beautiful, enormous Live Oak trees whose canopies hang over into our yard. This past week, they've begun dripping some sort of black sap all over our backyard. Is this normal, or some indication of something wrong with the trees? Thank you!ANSWER:
Most likely your tree has an insect called an aphid feeding on the foliage. Aphids are soft bodied insects and when they are numerous you can see the released sticky "sap-like" substance called honeydew. When the honeydew is numerous and stays on objects or leaves for a lengthy period a black sooty mold begins to grow on the sugary substance. Also bees and wasps are attracted to the honeydew that is being released by the aphids. Have an arborist take a look at your tree to determine if any action is needed. Aphids are a fairly regular visitor to Austin gardens - some years worse than others.
From the University of California Integrated Pest Management Program, here is an article on managing aphid infestations.
Also here's a link to a previous Mr. Smarty Plants question about aphids.
From the Image Gallery
More Pests Questions
Caterpillars eating passion vines from Austin
May 17, 2012 - My question concerns Yellow passion flower, purple passion vine & butterflies. I have had my passion vines for 3-4 years, each spring they start growing beautifully, then in 1-2 days are almost compl...
view the full question and answer
Possible maple scale on non-native mophead hydrangeas from Newport RI
August 07, 2013 - I have a mophead hydrangea that has small white cottony tufts under the leaves and on the stems. I believe this is maple scale. Is there a home remedy I can use to rid this disease?
view the full question and answer
Tiny holes oozing sap from Austin
August 22, 2012 - My ash tree becomes loaded with butterflies on the trunk. At closer inspection, I see they are drinking sap which is coming from small holes in the trunk. Are the butterflies creating the holes? I ...
view the full question and answer
Changing colors on Mexican Plum trees from Bellaire TX
June 20, 2013 - The leaves on my Mexican Plum tree have recently started turning yellow/brown and the veins in leaves are red. Is this a watering issue or disease issue? Mites are on the leaves. This has been a ra...
view the full question and answer
Cupressaceae dying in Suffolk Co.NY
October 20, 2012 - I have noticed that all of my Cupressaceae (& others I see in my area) are dying. They turn yellow, then rust & brown til they are everbrowns. what is going on?
view the full question and answer
| Support the Wildflower Center by Donating Online or Becoming a Member today. |