En EspaŅol

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
Can't find the answer in our existing FAQs, submit a question to Mr. Smarty Plants.
Need help with plant identification, visit the plant identification page.
 
rate this answer
4 ratings

Wednesday - August 08, 2012

From: Austin, TX
Region: Southwest
Topic: Diseases and Disorders, Trees
Title: Pecan leaves falling of the trees in Austin, TX.
Answered by: Jimmy Mills

QUESTION:

Why are the pecan tree leaves turning black, sappy and falling off the trees, in great quantities? This has happened since the recent rains, all through the Allandale area.

ANSWER:

Austin is presently experiencing an onslaught of honeydew. Honeydew is a waste-product of aphids and other sap-sucking insects such as scale. As honeydew is excreted by the sucking insects, it becomes airborne and falls and coats any surface upon which it lands in the area. Pecan trees are only one of several kinds of trees and shrubs that are being attacked by the aphids.

This article from University of Minnesota Extension, another from the University of Kentucky College of Agriculture,  and a third from the University of California Davis give a rather thorough explanation of honey dew and aphids, and their effects on plants. The blackening of the pecan leaves is because of an infestation of sooty mold that grows on the honeydew. This article from the USDA tells how to recognize and control sooty mold.
Another problem is that the sticky sap gets all over cars. This link has information about sap removal.

 

More Trees Questions

Native conifer bearing evergreen for noise reduction
April 01, 2008 - I asked the prior question about noise reduction and you gave me several choices. Thank you for that. Of the plants you suggested, the wax myrtle is the tallest and therefore probably best for my 2-st...
view the full question and answer

Need to know how to plant trees to create a windbreak in Ashburn, VA.
May 06, 2010 - I want to know how to plant trees to create windbreaks. I live on a slope of a hill, the front of the house is steep and the back of the house has neighbors in a cul de sac. I swear I live in a wind...
view the full question and answer

Cherry laurels next to retaining wall in Austin
September 18, 2010 - My neigbors have 2 cherry laurel trees in their back yard planted within 4 feet of my retaining wall and fence. I am worried the root system will damage my retaining wall. The branches are already pus...
view the full question and answer

Failure to thrive of Tex-ash in Tucson AZ
December 02, 2011 - I planted a mature (15') Tex-Ash about a year ago. Lately more and more leaves seem to be browning and it has never filled out. I am concerned I am going to lose it if I don't get it something befor...
view the full question and answer

Clicking heard under an Oak in near Bandera, TX
May 06, 2014 - Hi, I live on a ranch in TX outside of Bandera. We're covered with live oaks, spanish oak and cedar. Last week,as I stood under an oak, I heard a constant fairly loud clicking sound under and around ...
view the full question and answer

Smarty Plants's Facebook profile Support the Wildflower Center by Donating Online or Becoming a Member today.

Mr. Smarty Plants wants you to be his Facebook friend. Click the Facebook icon to add yourself to Mr. Smarty Plants list of friends.
E-NEWSLETTER | BECOME A MEMBER | DONATE NOW | MEDIA | SITEMAP
© 2014 Lady Bird Johnson Wildflower Center