Friday, June 7, 2013

Catching pecan nut casebear moths

    We set up pecan nut casebearer (PNC) pheromone traps after last weekend's flood receded (photo at right, arrow points to trap). However is wasn't until we got a warm night (above 60 degrees) that we found large numbers of male moths in the traps the next morning (Thursday June 6).
  In setting out PNC pheromone traps, I like to place the trap as high up into the tree as possible. To make checking traps a ground level operation, we use a rope and pulley system to raise the trap up into the tree's canopy and to lower it for counting moths.

    The photo at left shows the simple pulley system we use for hanging traps. We start with a 2 foot piece of 3/8 inch steel rod and bend it into the shape of a huge fish hook. At the long end of the steel hook we drill a 3/16 inch hole then place a loop of "bailing wire" through the drilled hole. The wire loop acts as our pulley for the braided nylon cord used to raise the trap up into the tree.
   The steel hook is placed over a limb using a 20 foot long piece of 1 inch diameter PVC pipe. I start the installation process by threading an ample amount of nylon cord through the wire loop on the end of the hook. I then place the long end of the hook inside the pipe (with cord hanging out). Lifting the pipe upright, I place the hook over a tree limb. This will get the trap about 25 feet up into the canopy, a height where PNC moths are actively flying.  To hold the cord in place and the trap high in the tree, I pound a nail into the trunk of the tree and tie the cord to that nail.

    The photo above is an example of one of our pheromone traps. We use a trap that has a plastic top and cardboard bottom.  We've found the plastic top helps to make the trap more rain proof.  The cardboard bottom is covered in a sticky substance that ensnares male moths as they enter the trap. The little grey stopper inside the trap is what contains the PNC pheromone. This trap had captured 16 moths.
Here's  a close-up of a PNC moth caught in a trap (photo at right). The casebearer moth is small, grey and cigar shaped. However, PNC moths have a distinctive ridge of scales across the upper third of their forewings. You might find other insects caught in the trap but only PNC moths will have that ridge of scales.