Insects and Your Nut Trees

There is nothing more frustrating for a gardener than opening a homegrown pecan only to find worms crawling around within. Insects that infest nut trees can wreak havoc causing thousands of dollars in damages to lush groves, so keeping insects under control is important. Listed below are a few insects gardeners should know about.

Walnut Husk Fly Maggot

After spending the winter underground, this maggot comes forth in the middle to late summer as a fly. Upon reaching adulthood, it lays its eggs in the husks of black or Persian walnuts. The hatchlings feed on the husk causing damage to the inner shell, which may cause the kernels to be unable to develop their full flavor. To help control of the Walnut Husk Fly Maggot, spray every two weeks using carbaryl or malathion sprays in July and August.

Pecan Weevil

Adults Pecan Weevils, which feed on young nuts, lay their eggs in the husks of both pecans and hickory nuts. The eggs hatch into grubs and bore through the shell to feed on the kernel. Sprays, which need to be applied throughout the summer months, are the only defense in combating this pest.

Hickory Shuckworm

Adult moths lay their eggs on or near pecan and hickory nuts, which then hatch into caterpillars that feed on the nut and husks. These caterpillars will bore into the nut right when the shell hardens to feed on the kernel, causing the nut filling to be underdeveloped. Control involves removing fallen husks in fall and early spring, and the removal of immature nuts during the growing season.

Pecan Nut Casebearer

These caterpillars, which are enclosed in cocoons attached to twigs on pecan, black and Persian walnut, and hickory trees, emerge in spring to feed on the tree buds and then move into new shoots. These caterpillars then turn into moths, which lay their eggs when new nuts start to form. To help control of the Pecan Nut Casebearer, spray newly hatched eggs with carbaryl or malathion.

Stinkbugs and Spittlebugs

These are juice-sucking insects that feed on young nuts. Damage results in the way of nuts dropping off prematurely, the kernel turning brown, and/or the kernel becoming shriveled. Control involves keeping grass and weeds mowed around the tree as these insects are prevalent in those conditions.

Leaf or foliage-eating insects including webworms, Eastern tent caterpillars, walnut caterpillars, and hickory tussock moths, just to name a few, also attack and cause major damage to nut trees.

Source: Mastergardenter classes