Old Native Pecan Yard Tree

Asked July 1, 2015, 6:10 PM EDT

I have had the lot with this pecan for 23 years. We experienced an unusual high rainfall this Spring, but it has good drainage with 4" yard drain. It never had any build up of additional soil and the soil was not compacted by equipment from the day we started house construction. It is watered 3 time a week with our irrigation system. It has been been cleared of sucker growth and deep root fertilized for 22 years every 2-3 years. The last being 2 years ago. It had a good nut production last season. There are no large cavities. It has never looked stressed in the highest branches as it is now. I have one large limb that cannot be seen in the photos that looks normal. What should I do?

Fort Bend County Texas trees and shrubs pecan horticulture horticulture

3 Responses

Howdy!

Trees in our region are still dealing with prolonged stress stemming back to 2011. Several things may be going on here.

1. weakened branches from lack of moisture. Even in irrigated areas, when the water table decreases as it did in '11, the trees suffer from lack of deep root moisture. This will show up as twig and branch dieback.
2. Squirrel damage. They can remove bark on upper branches and cause the branches to die off. Not much to do on this one.
3. Twig girdlers. These are insects that remove bark and make branches fall to the ground, where they have eggs laid in. Again, not much you can do on this one, but to pick up fallen branches and discard asap.
4. Walnut caterpillars. These have been eating all the leaves off trees in our area for 3 years now. From the image, the leaves look small and they may have done some damage to the canopy. Check out this article I have attached. It may shed some light on the topic.

http://fortbend.agrilife.org/the-walnut-caterpillar-round-3/

Beyond all this, you may want to hire a certified arborist to review the tree and offer root stimulation and pruning advice and services.
http://www.isa-arbor.com/findanarborist/findanarborist.aspx

Best of luck. Good day,

Boone

Boone,

Thank you for your reply. The tree shows signs of continued dieback. Can someone from your office verify that my problem is the Walnut Caterpillar? If it is, is this fatal to the tree if it is not sprayed with insecticide. One certified arborist stated, after looking at the tree, that it may have wet feet after the unusually wet Spring. The tree never stands in standing water as I have a efficient 4" drain within 10 to 15 feet from the trunk. Could there be a root issue? It has not had a deep root feeding in about 2-3 years. Would that help?

Howdy, again. Ok, here we go.

1. You would see the walnut caterpillars. They are about 2 inches long and black with white hairs at maturity. If you don't see any of them or see that leaves are being eaten, this isn't part of the problem. No, they will not directly kill the tree, but do cause added stress to already weak trees.
2. The water issue. So, we are seeing many established trees showing signs of shock, where leaves are falling or are browning on the tree. This may be part of the wet/dry complex. The water table was real high in May and surface drainage can't help that. High water table causes root dieback. Then, we got hit with a real hot dry summer. Trees get shocked by this. So now, watering appropriately is a careful maintenance to limiting stress.
3. Pecan trees are big time users of soil nutrients, especially Nitrogen, which is integral to plant growth. A certified arborist can offer you a fertilization plan to help get the tree wanting to grow. This may be a combination of commercial fertilizers, compost products, and root and bio stimulants.

Good luck. Please, if you have additional questions, please contact me through my direct email listed below.

Thanks, Boone