Pecan weevils damage pecan and hickory plants in two different ways. Once the adults emerge from the soil between late July to October their cycle of damage begins.
- The adult weevils feed on kernels before the shells harden up. Many of these infested nuts will not mature properly and have a shriveled appearance.
- Late in the growing season, adult females lay their eggs in newly formed kernels. Once the larvae hatch, they feed on the kernel for about 35 days. Their presence does not stop development of the pecan so they may make it into the harvest. But it does cause the nuts to be inedible.
- To keep the adults from traveling from the soil to the nuts (from late August through October) apply Tangle Trap or Stiky Stuff around the base of the trees. This will trap and stop the adults.
- Apply beneficial nematodes to the soil around the trees during the time the larvae are in the soil. This occurs between September and December.
- Use Beauveria bassiana weekly to the tree and the soil. This is a bio-rational insecticide that will help control the population of pest. B. bassiana will not harm beneficial insects and will have some effect on each stage of the life cycle.
We've listed other control options, but using the 3 options above, on a consistent and timely basis will help keep the populations from causing economic damage to the pecan crop.
For information about different species of weevil click here.
Photo courtesy of Clemson University Department of Entomology, Soils & Plant Sciences, Cooperative Extension Service.