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Wednesday, October 16, 2013

Broken twigs caused by long-horned beetle

   This week, I've been back up in pecan tree canopies collecting nut samples from our breeding plot. When I'm up in the hydraulic lift I get to see things I might not notice from ground level. High-up in one tree, I found a branch that looked like it was cleanly broken in two with the leaves above the break dessicated to a crispy brown (photo at right).

     Moving in for a closer look, I found that the branch had a clean break--almost like it was partially cut by a pruning tool. This type of clean break is the tell-tale sign that the limb had been attacked by a long-horn beetle called the twig girdler. You can find a photo of an adult twig girdler and the details of this beetle's life history in a post I made previously.
     The female beetle lays eggs in the branch above the girdle. These eggs will hatch next spring and larvae will feed on the recently killed twig. If you find neatly broken off limbs on the ground under your pecan trees this harvest season, it is a good idea to pick up those twigs and burn them to destroy next year's crop of twig girdlers.