ASK THE HORT AGENT
Question What is causing pecan limbs to fall all over my yard?
Answer Pecan limbs have a habit of breaking off for no particular reason. Placing picnic benches under a pecan tree is not a smart idea. Proper pruning of young pecan trees will reduce the number of falling limbs. On the other hand, trees which have been topped are more likely to have limbs fall during severe weather events.
This time of year, a bug called the pecan girdler is probably doing some unauthorized pruning. They are also called twig girdlers. When people call my office, my Southern accent often prevents people from understanding my pronunciation of the word girdler. I end up referring to a lady's undergarment (girdle) and then imitating the Budweiser frog by saying "er".
Surprisingly, this large beetle does more good than harm to your pecan trees. It lays eggs under the bark of twigs and then cuts the twigs off the tree. Larvae hatch from the eggs and feed in the branch. Eventually they pupate (change into a beetle) inside the twig. Nearly a year later, adult beetles emerge from the twigs and start the cycle again.
The cut made by the adult is very uniform and circular. The twigs are usually about the size of a man's finger. The adult beetle cuts around the twig until the weight of the twig breaks it off the tree. Hence, the center of the twig will be the only part that does not look smoothly cut.
This beetle only has one generation per year. The best way to control the pecan twig girdler is to pick up the fallen twigs (which contain the eggs) and destroy them. This insect is actually pruning your tree and causing it to be more productive. Unlike the practice of “topping,” girdlers are cutting small limbs which encourage branching near the productive tips.
People really get ticked off when a twig girdler has cut the top off of a newly planted pecan tree. Once again, the insect knows best. It is recommended that one third of a newly planted tree be cut off when a pecan tree is planted. Most folks can't stand to cut two feet off of the six foot tree that they just planted. The twig girdler will gladly do it for you if he is in the neighborhood. This bug is weis-er than most folks realize. For more info about the twig girdler, visit http://extension.missouri.edu/xplor/agguides/pests/g07276.htm If you don’t have internet access, then call me at 893-7533 or email me at firstname.lastname@example.org
Thunderstorms and hurricanes also cause pecan limbs and nuts to hit the ground. Ahhh, there’s nothing like the sound of pecans falling on a tin roof at night. The sound of pecan limbs falling on a tin roof may not be as pleasing.
Gary L. Pierce
Horticulture Extension Agent