En EspaŅol
Share

Ask Mr. Smarty Plants

Mr. Smarty Plants - Pecan leaves falling of the trees in Austin, TX.

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

Transplanting Desert willows in El Paso, TX
August 27, 2009 - We have some volunteer Desert Willows growing on an empty lot nearby. Can we dig them up and transplant them in the yard? If so, how? They are about 3-4 feet tall
view the full question and answer

Should hole in escarpment live oak be filled in Austin?
May 24, 2009 - Regarding one of my mature escarpment live oaks: should an old hole (about 8" across) in the trunk (caused by the improper cutting of a branch) be filled? A tree service technician advised me that he...
view the full question and answer

Installing limestone walkway around trees from Pflugerville TX
June 28, 2012 - Dear Mr. Smarty Plants:I wish to install a limestone walkway in my front yard, however, there are some roots(~ 1.25 inch) in the designated area. Will this hurt or kill the tree if I cut these away? T...
view the full question and answer

Tilling for grass under old live oak in San Antonio
April 15, 2012 - Hi, I have a 250+ year old Texas Live Oak. As usual, the lawn under the tree, after 18 years needs to be redone. MY QUESTION: to put down new sod the lawn company needs to till the soil about 4 t...
view the full question and answer

Fast-growing medium-sized tree for New Jersey
July 06, 2013 - I'm looking for trees to put on a slight slope that will do well in rocky clay soil. I 'm in N.J. zone 6. The spot is full sun and would like a fast grower 50 ft high maximum. I'm replacing white p...
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