Pecan growers learn to 'hedge' their crops

By MANDY JOHN | Central Texas Edition

Dr. Tommy Thompson, center, shows pecan growers what happens when plants don't receive enough zinc. -Staff photo by John

August 29, 2002 -- Pecan growers had an opportunity to learn about growing healthy and plentiful pecan trees and how to protect their trees from such insects as pecan weevils at the Pecan Field Day held Aug. 21, 2002 in Comanche.

Bill Sorrell has been the owner and manager of Four-Okie orchard for the past seven years. He grows Tejas pecan trees, one of many types of pecan trees.

Other types include the Hopi, Navaho, and Pawnee pecan tree.

He said that the trees in his orchard "were planted 24 years ago and today the pecans are larger than they have ever been, although I am not sure how the pecans have filled out." He attributes that to hedging, which is cutting down barren wood from trees to make room for the healthy limbs that contain pecans.

Sorrell said, "In the past, the trees were not producing a lot of pecans and of the pecans that did grow, they were not so good. Then I decided to hedge the orchard." He said that due to hedging, six feet of new growth emerged from the trees, although no new pecans have formed yet. Sorrell recommends cutting, at the most, 30 feet on the top hedge and going down from there. He also recommends hedging in a north-east and south-west direction instead of the typical north-south and east-west direction. He does this so that the "north side gets as much sunlight as the rest of the tree".

Ten years ago Sorrell tried another tactic to promote pecan growth by taking out every other row of trees in his orchard. He said that doing this has helped his trees to grow and has also allowed enough sunlight and water to reach all the trees, because they are not competing with so many other trees.

Sorrell said that he built his business on good quality pecans and wants to continue that tradition.

Dr. Tommy Thompson, research horticulturist from Texas A&M University, continued the discussion about hedging by explaining the benefits as well as what happens to the trees when they are hedged. Thompson said that the main problem with Tejas trees is that they create a thick orchard. He explained that this was a problem because of the limitations with water. "If you get water from a water district, then you are limited to the amount of water you get. This causes trouble in getting water to all the trees," he said. Thompson feels that hedging would help in this water situation by getting rid of the barren wood on the trees. He also stressed that sunlight is extremely important to good pecan production.

Thompson reminded growers that pecans always need to be cross-pollinated and that quality is a big factor when it comes to growing pecans. "By hedging, not only will quality remain good, but production will go up as well," he said. According to Thompson there is no exact way to hedge a tree in order to get more pecans, but hedging will always be a key factor in production.

"With hedging comes healthy regrowth," Thompson said. "Growers need to make sure that the leaves have enough zinc in them because zinc helps the leaves grow and expand. If the leaves do not have enough zinc, they will become deficient and black spots will start to appear. This means that the leaves are dead and pecans will not grow."

The one area that research is needed, he said, was the relationship of hedging to regrowth.

Bill Ree, Extension pecan entomologist, pointed out that protecting pecan trees from insects, especially the pecan weevil, was of great importance. According to Ree, "the pecan weevil is a key pest of pecans in the United States and portions of Texas with pproximately 80 percent of adult weevils emerging between August 20 and September 10.

"Only possible time to manage infestations is after adults have emerged from the soil and before egg laying starts." Ree said the emergence of adult pecan weevils is directly related to the type of soil as well as soil moisture conditions.

To prevent weevils from laying eggs he suggested that pecan producers do the following:

• Monitor kernel development to determine when the earliest maturing cultivars reach a stage susceptible to oviposition;

• Monitor adult emergence from the soil; and

• Apply an effective insecticide at the proper time to prevent emerging weevils from laying eggs in susceptible nuts.

Ree said females can't lay eggs in kernels successfully until the kernel is fully developed. "So check tip of kernel."

There are three types of weevil traps, he said: the wire cone trap, the pyramid trap, and the circle trap. He said each trap has benefits as well as drawbacks.