Pecan Nut Casebearer

This is the time of year when we become concerned about pecan nut casebearer infesting pecan nutlets. Casebearer will overwinter in a hibernaculum or cocoon and then break dormancy to begin the process that gets us to this time of year. We are now seeing the moths emerge from this process and it is these moths that will lay eggs that become the first generation pecan nut casebearer. The way we know when the moths are flying is not because we look for the moths laying eggs but that we have installed moth traps in the trees.
These traps have a pheromone inside the trap that attracts male casebearer moths. We put the traps up in the orchard about a month before we expect to see moths so that we know when the moths begin coming into the orchard. We examine the traps every 2-3 days or 3 times a week and record the number of moths captured and then remove the moths. This record of moth catches help monitor the time moths numbers are highest. Once we capture moths then 7 to 10 days later we should begin to see eggs laid on nutlets. Once eggs are laid it takes 4-5 days to hatch and 1-2 days before they enter the pecan. Scouting is very important to make this program work. This past week I had reports from several commercial growers that they had moth catches in their traps. Following the above schedule we should begin to find eggs on the pecan nutlet about May 8 or 9 and possibly nutlet entry on May 13-15. We look for either eggs or entries till we find 2 or more infested clusters of pecans out of 310, then we spray.

Commercial orchards use chlorpyrifos at 1-2 pints per acre, Confirm, spinosad, Sevin, and Bt for pecan nut casebearer control. Homeowners can use Dipel or Javelin both are organic products with bacillus thuringiensis or Entrust with spinosad which is also labeled organic. Two other products are Sevin or malathion. Follow label directions and be sure to get good coverage, moths tend to work the tree tops as well as the bottom.
Once you know when the casebearer is laying eggs mark your calendar because exactly 6 weeks later you can expect the second generation to show up. Sometimes we don’t treat for the second generation because there just aren’t enough to justify the cost but still scouting is important so that we know. (Thanks to the University of Georgia for great PNC pictures!)