Tuesday, August 20, 2013

Pecan weevil nut drop

   We discovered this cluster of Posey nuts while collecting leaf samples today (photo at right). The nut cluster had 5 nuts with three of the nuts streaked with brown necrotic areas. This didn't look good.
    I pulled off one of the damaged nuts for a closer look (photo at left). On one side of the nut I found an obvious puncture wound in the shuck (at end of red arrow). I could tell this puncture extended all the way into the kernel because of the shiny black stain on the outside of the nut husk. The kernel was punctured allowing liquid endosperm to leak out of the nut, onto the shuck and turning black as it oxidized.  In three days we would be finding dry, blackened pecans on the ground.
      I cut open one of the damaged nuts to inspect the kernel. The interior of the nut had lost its normal, light-green coloration. The entire contents of the nut had turned brown. Between the size of the puncture wound and the brown discoloration of the kernel, I can state with confidence that this nut was a victim of  pecan weevil feeding. Not only that, it was probably just one adult weevil damaging all three nuts in the cluster.
   Because nut development is so far behind normal, pecan weevil feeding damage will be an all too common problem this year. This is exactly the kind of feeding damage we were trying to prevent when we sprayed last week. Looks like we missed one.