Question: Our pecan tree is constantly dropping limbs. They look like they’ve been cut off with a knife. What can we do?
That’s damage of twig girdlers. They’re fairly large insects. The female lays her eggs near the ends of the twigs, then cuts almost all the way through the limb. Several months later, the dried twigs will break and fall to the ground. The developing larvae are in the twigs, so raking and removing them is the best control. There is no chemical spray that will work, since the adult is there such a short time, and since the larvae are in the dead wood.