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 Diseases and Disorders Questions

Leaf problems on oaks in North Liberty IA
June 12, 2010 - My oak trees (young and old) are showing leaf problems. Is there a disease or insect causing oak tree disease?
view the full question and answer

Insect damage on possumhaw
August 12, 2012 - We planted a small possumhaw in February of this year (2012). It had leaves and some berries and was doing real well until some bug starting eating the leaves and berries. I know it is not deer becau...
view the full question and answer

Recently planted Chinquapin Oak with browning leaves in Marlin, TX.
July 31, 2012 - We planted a Chinquapin Oak this in March 2012. As of July 21, 2012, the tips of the leaves on the lower branches are turning brown. We cannot see any insects. There does not appear to be any fungu...
view the full question and answer

Pruning live oak shoots from San Antonio
September 10, 2011 - I am new to TX and am curious about removing suckers/water sprouts from my Live Oaks. Everything I've read about pruning Live Oaks states that you must paint ALL cuts, so I assume that all means al...
view the full question and answer

Identification of gooseberry plant
July 12, 2007 - Grew up in Colorado, our yard and several near us had medium to large size deciduous shrubs that produced small (.25"-.375") red berries that were very tomato-like. Delicate with a thin skin, sligh...
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 | STAFF
© 2015 Lady Bird Johnson Wildflower Center