En Español

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?


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

Please forgive us, but Mr. Smarty Plants has been overwhelmed by a flood of mail and must take a break for awhile to catch up. We hope to be accepting new questions again soon. Thank you!

Need help with plant identification, visit the plant identification page.

rate this answer
1 rating

Friday - June 11, 2010

From: Huntsville, TX
Region: Southwest
Topic: Trees
Title: Pecan with brown spots on the leaves
Answered by: Nan Hampton


Southern pecan, I am a 8 foot tall and 3 year old (young)tree. My leafs have brown spots on top and hard shell mound on the bottom, this is on about 3/4 of the of the leafs, could you tell me what this is and how to fix it? Thank You.


Mr. Smarty Plants is very sorry you are ailing.  I would like to compliment you on your communication skills, however!

I consulted several sites that had information on diseases and pests of pecans.  University of Missouri Extension's Pecan Pest Management: Insects and Diseases, University of Arkansas Cooperative Extension's Home Pecan Diseases and Control, Louisiana State University's Agricultural Center's Pecan Disease Synopsis, Clemson University Cooperative Extension's Pecan Diseases, and Texas A&M University Cooperative Extension's Pecan Kernel Diseases.

Your symptoms didn't sound exactly like any of the ones listed, but here are the diseases or pests with  symptoms that most closely resembled yours: 

1) Downy spot fungus caused by Mycosphaerella caryigena

2) Pecan Phylloxera caused by the insect, Phylloxera devastratrix

3) Zonate leaf spot caused by the fungus, Cristulariella moricola

4) Brown leaf spot caused by the fungus, Cercospora fusca

Most of the descriptions of the above conditions offer recommended control measures.

You can also read a rundown of pests and diseases affecting Carya illinoinensis (pecan) from the U. S. Forest Service.

Since pecans are considered agricultural crops you might like to visit Texas AgriLife Extension "Ask an Expert" to ask them the same question.  They are likely to have a plant disease expert on hand who knows pecan tree diseases better than we do.


More Trees Questions

Preventing Oak Galls
February 22, 2016 - How do you prevent live oak galls? Do you have a solution? Many of our live oaks are infested with them.
view the full question and answer

Aging Arizona Ash in Austin
May 04, 2014 - Mr. Smarty Plants! I live in South Austin and just bought a house with a large, 30-40 year old Arizona Ash in the backyard. When I moved in, most of the lower branches were bare and dead and so I had ...
view the full question and answer

Willow Tree Early Leaf Fall
May 14, 2015 - I have a weeping willow tree and it put out great leaves this Spring and looked great, but now here in the middle of May all the leaves are turning yellow and falling off like it does in the fall. So ...
view the full question and answer

Need suggestions for trees with non-invasive root system in Paramus, NJ.
August 23, 2011 - What trees can I plant in New Jersey with non invasive root systems? We lost our tree to a storm and are looking for a viable replacement.
view the full question and answer

Possible identification of Post Oak in New Braunfels, TX
January 27, 2006 - I live 6 miles north of New Braunfels in the Hill Country and own 5 acres of land. The property consists of many escarpment live oaks, texas persimon, and ashe juniper. I believe I also have some Te...
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.
© 2016 Lady Bird Johnson Wildflower Center