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
Do Deer Eat Orchid Trees?
March 08, 2013 - I have planted three anacacho orchid trees, however we have a lot of deer around us. Is this a tree they will want to eat? Do you have any ideas to keep deer away?
view the full question and answer
Bugs on Arizona Cypress in Bellwood IL
August 27, 2011 - I live in Illinois and have an Arizona Cypress that looks like it is dying but I notice today it has bugs inside its cone. Can you tell me why and what can I do?
view the full question and answer
Disappearance of leaves on desert willow in Tucson AZ
August 08, 2009 - We have a Lois Adams Desert Willow (Tucson, Az). The leaves will pump out and then a day or so later, all of the leaves are gone. The only bugs we've seen on it are very, very small ants. Could this ...
view the full question and answer
Possible webbing bark lice on oak tree
August 08, 2008 - We live near the Center and have a large live oak tree in our yard. Recently the lower trunk has been covered with thin, white weblike material (not sure if spider web). What could this be and is it d...
view the full question and answer
Problems with non-native yellow lantana from Elgin TX
June 17, 2012 - Why do my yellow lantana buds turn brown and do not open fully? The sprinkler system does not spray onto the lantana.
view the full question and answer
| Support the Wildflower Center by Donating Online or Becoming a Member today. |