Adults overwinter near host trees in leaf litter and brushy areas filled with debris. They emerge in spring (around mid-April) and migrate to tender, rapidly growing shoots where the females will feed and lay their eggs. Larvae will hatch and begin burrowing into shoots shortly afterward, creating a tunnel. When the hickory shoot curculio larva completes its development, it comes out of the tunnel (Figure 4) and drops to the ground where it pupates for 2 to 3 weeks. The adult weevil emerges from August to September, feeds for a little while, and finds a well-sheltered area to pass winter. This insect has only one generation per year.
Figure 3. Tunnel caused by hickory shoot borer in pecan. Larva is legless and with a brown head (Photo: Raul Villanueva, UK)
Figure 4. Hickory shoot borer emerging from pecan shoot (Photo: Raul Villanueva, UK)
Cultural controls are the most effective management tools when populations are low and infestations sporadic. Cultural controls include eliminating brush and debris to limit hibernation sites around trees, collecting all damaged tree shoots from the ground, pruning affected parts, and burning infested shoots outside the orchard. Establishing new plantings away from infested woodlots also helps but is often impractical for homeowners and smaller growers. Chemical control is usually not warranted, unless there is a consistent history of this pest in an orchard. Preventative sprays to control adults before they lay their eggs can be done starting in mid-late April or early May when shoots are 1/4 to 1 inch long. Insecticide treatments after the larvae have entered the shoots is ineffective.