Disease in Pecan Trees

Pecan scab disease on leaves of pecan tree image by USDA, Rob Flynn: Bugwood.org


Pecan trees produce nuts loved by people around the world; squirrels love them, too. Some huge pecan trees produce hundreds of pounds of the tasty treats. Like every other plant and tree, though, insects and disease cause problems for the orchard owner and backyard gardener. You can do certain things to prevent diseases. However, if it's too late and the disease is already present, it's important to start control immediately because waiting too long may cause the death of your beloved tree.

Pecan Tree Diseases

Step 1

Ask a nursery employee which fungicides to use to prevent specific diseases; there are many different types. Mix the fungicide with water in a one-gallon container according to the manufacturer's directions. Pour the mixture into a tank sprayer set aside strictly for the fungicide, then spray the trees.

Step 2

Spray your pecan trees four to nine times per year to control pecan scab disease; it is the most common disease affecting pecan trees. It appears as green spots that turn black on the leaves or nuts, and spreads very fast. Unsprayed trees lose their leaves prematurely, which adversely affects the number of nuts available in the following year.

Step 3

Use large pruning shears for small branches or a chain saw for large branches to cut them off the tree if only a few have bunch disease. Take the cut branches far away from the tree to prevent further infection. If seriously infected, you'll have to destroy the trees, as there's no way to control this disease. This disease's characteristics are bushy growths of thin shoots.

Step 4

Prevent cotton root rot on new pecan trees by making sure the soil is well-drained. Once infected with this disease a tree will die quickly; there is no way to cure it.

Tips and Warnings

  • Fungicides are toxic to fish, animals and humans. Wear protective goggles and clothing when spraying your trees. Don't let your pets or children into the yard where the tree is until the spray is dry.

Things You'll Need

  • Fungicide
  • Water
  • One-gallon container
  • Tank sprayer
  • Large pruning shears
  • Chain saw


  • University of Missouri, "Pecan Pest Management: Insects and Diseases"
  • Oklahoma State University, "Bunch Disease"
  • Texas A & M University, "Evaluating Pecan Problems"

Who Can Help

  • University of Florida Extension, "The Pecan Tree"
Keywords: pecan tree disease, pecan scab disease, bunch disease, cotton root rot

About this Author

Ellie Kuykendall has been writing and editing professionally since 1997. Her travel and insurance articles have appeared in national magazines. She's contributed to four books and is currently writing her own book. She received a bachelor's degree from University of San Francisco.

Photo by: USDA, Rob Flynn: Bugwood.org