Friday, August 25, 2017

Pecan kernels filling - pests on the prowl

    The other day I cut open pecans from a few cultivars of pecans and discovered just what I expected. My pecans had started the kernel filling process (photo above, right). At this point during the growing season, the seed inside the shell has formed a thin layer of kernel tissue just under the seed coat. The amount of kernel deposition by late August is both weather and cultivar dependent. Earlier ripening cultivars will fill their kernels sooner that later ripening cultivars.

     As soon as pecans start to fill their kernels, two important pecan pests attack: Pecan weevils and squirrels. Since we've experience above normal rainfall for the month of August pecan weevils have been emerging continuously since late July (photo at left). However, female weevils will not lay their eggs inside the pecan until kernels start to fill. So with the kernel filling process underway, we applied our second weevil spray to our trees this week (August 23 & 24) to control both pecan weevil and stinkbugs.  For growers with high weevil populations be prepared to make a third weevil spray in early September.
    The kernel filling process also marks the time when squirrels start cutting open pecans in search of a meager meal of partially formed nut meat. This kind of squirrrel damage largely goes unnoticed by growers but we have begun to collect lots of nut fragments in drop cages set under native pecan trees (photo at right). Although, we might never claim complete victory over squirrels, we've been trapping squirrels in coni-bear traps since early summer to help reduce the resident squirrel population.