The flatheaded apple tree borer attacks pecan trees as well as apples and damages stressed or newly planted pecan saplings. Proper care of new pecan trees, including irrigation and fertilization, will help the trees resist infestations. Machine damage from mowers could create an entry point for boring insects, and any dead wood left on the tree in the springtime could perpetuate the cycle of infection. Extra protection in the early years prevents insect injuries which could severely damage or kill the pecan tree.
Wrap the trunks of newly transplanted pecan trees with overlapping layers of heavy parcel wrapping paper. Tie the paper in place with garden twine, and leave the wrap on the tree for the first two years. Tie the twine loosely to avoid girdling the tree.
Mix carbaryl insecticide according to the manufacturer's directions, and spray exposed areas of the tree's base, trunk and major branches. Apply this preventive solution at three week intervals during the growing season, beginning in early May when the first pests emerge.
Check trees for borer damage during the growing season. Look for patches of wet or discolored bark and for piles of frass or borer excrement. Boring larvae excrete sawdust as they feed, and the remains mark the location of tunnels. Remove or kill borers manually if possible by inserting copper wires in the tunnels. Don't leave the wire in the tree.
Prune out any dead wood on the tree in late winter before weather warms and insects emerge. Rake up any fallen twigs or limbs on the ground beneath the trees. Gather and burn all the debris to destroy any insects overwintering in the wood.