Friday, August 3, 2012

Pecans in the water stage

   Spring came early this year and many of our summer fruit crops ripened 2 to 3 weeks early. Not so for pecan. This summer's heat and drought has slowed pecan kernel development to a point where kernel development now is right on schedule. It's early August and nuts are in the water stage (photo at right).
   The water stage of pecan kernel development can be defined as the point in time when the shell and kernel seed coat have become fully sized and the interior of the kernel is filled with liquid endosperm. Cut a nut open at full water stage and your hands will be soaked by the water that comes pouring out.
   In the photo above, Osage and Kanza are in full water stage while Maramec is still expanding it's kernel (its in 3/4 water stage). At this point, you can also see that the shell has become hardened especially near the nut apex and the inner shell packing material between kernel halves is starting to be compacted by the expanding kernel, turning orange in color. 
    Understanding the stages of kernel development is important for understanding how kernel feeding insects damage pecans. If a pecan weevil or stink bug punctures a nut during the water stage (or any time before water stage) that nut will drop off the tree. Once kernel deposition starts (the gel stage) insect damaged nuts will remain on the tree until harvest.