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Tuesday, May 24, 2011

Trapping Pecan Nut Casebearer

    The pecan nut casebearer is a major nut feeding pest. Shortly after the pollination season casebearer moths lay eggs near the tip of young nutlets.  The larvae that hatch from these eggs crawl down to the base of a nut and start feeding. The insect chews its way into the center of the nut, hollowing out the inside. You can identify casebearer feeding by the light strands of webbing the caterpillar uses to fasten nuts to the stem (so the damaged nut doesn't fall off) and by the pile of frass at the base of the nut (photo above).
     Each spring, we monitor the activity of the insect by using pheromone and orchard surveys.This year, I've enlisted the help of several growers around the state of Kansas to follow this year's casebearer moth flight using pheromone traps.

    Pheromone traps are easy to use as long as you can identify the target insect.  In the photo at left, two male casebearer moths have become stuck in a trap. The moths are grey, about 3/8 inch long, and feature a prominent ridge of scales across their wings. You can see other insects caught in the trap and even a fallen catkin, but casebearer moths will be the only insect that have a ridge across their backs.
    The spring 2011 flight has begun in the southern most areas of Kansas as of May 20.