What Major Insects Harm Pecan Trees?

— Written By NC Cooperative Extension

In North Carolina we have four insects that economically can affect the pecan crop.  These insects are pecan weevils, twig girdlers, stinkbugs, and aphids.  

The pecan weevil attacks the nut and is the most serious pest of the pecan crop.  The adult is a beetle like insect with a long slender snout.  The pecan weevil is reddish brown to gray in color and is approximately one half an inch in length.  Pecan weevils cause damage by puncturing the nuts and the larvae feeding within the nut.  They over winter in the soil around pecan trees and the adults emerge from August through September.

The twig girdler is also a beetle that chews on twigs and small branches in September.  The female lays eggs in the chewed area of the twigs and/or branches.  During storms or heavy winds, the branches break off and fall to the ground.  The larva leaves the twigs and/or branches to burrow in the soil and begin to pupate.

Stink bugs attack pecans by puncturing nuts before and after the shell hardens.  The stinkbug causes black spots to develop on the kernel and gives the nuts a bitter taste.  They over winter in debris and emerge in the spring to lay eggs.

Yellow and black aphids attack pecan trees by feeding on the leaves.  As the aphids feed, they deposit honeydew on the foliage and in return black sooty mold fungi develops.  Aphids over winter in bark crevices.  Damaged leaves show yellow patches and often turn brown and die.

Reminder:  The Sampson County Master Gardener Phone Hotline and Plant Clinic takes calls every Tuesday and Thursday from 10 am to 3 pm.  The Hotline will observe these operational hours through the end of August.  Please call the Sampson County Cooperative Extension Center at (910) 592-7161 with your horticultural questions and ask to speak with a Master Gardener.  Be sure to check out the Ask An Expert Widget at sampson.ces.ncsu.edu for any questions you may have.

For more information, please contact Della King, Sampson County Horticulture Extension Agent at 910-592-7161.

Posted on Jul 23, 2009
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