Hickory shuckworm

About

A small dark moth whose cream-colored caterpillars feed in the green shucks of pecans and hickory nuts. Damaged nuts fill poorly or drop early (Texas A&M; Oklahoma State).

Spotting it

Damage

Summer caterpillars inside young nuts make them drop; fall caterpillars tunnel in the shucks, so kernels fill poorly and shucks stick to the shells instead of opening ('sticktights') (Texas A&M; Oklahoma State).

How to find it early

Look for single creamy-white egg smears on the shucks, early nut drop in summer, and shucks that won't open in fall (Texas A&M).

When

Moths from mid-April; the worst damage from midsummer to harvest.

Life cycle

It spends the winter in old shucks on the tree or ground and has several generations a year (three in Oklahoma); each caterpillar feeds in a shuck for about 15 to 20 days (Oklahoma State; Texas A&M).

What to do, gentlest first

Start at the top. Sprays are a last step; always read and follow the product label.

1. Clean up old shucks Prevent

   Rake up and destroy old shucks and dropped nuts, where the pest spends the winter (Texas A&M).

2. Spinosad Organic spray

   Only where it has been a problem before: spray when nuts reach half-shell hardening, and again 10 to 14 days later if needed (Texas A&M).

   Big trees are hard to cover from the ground. Follow the label.

Plants it goes after

Pecan

Pressure by region

Our sources cover Texas and Oklahoma only; the regional ratings are estimates based on where pecans and hickories grow.

Ratings come from extension sources where available; some are estimates, as noted above.