Pecan nut casebearer

About

A small gray moth whose caterpillars bore into tiny pecan nutlets in spring. Texas A&M calls it the most damaging pecan pest; it occurs in pecan areas from Florida to southern New Mexico (Oklahoma State).

Spotting it

Damage

Caterpillars tunnel into young nutlets, and one caterpillar often destroys every nut in a cluster; look for silk and black droppings on the nuts (Texas A&M).

How to find it early

Right after pollination, check about 10 nut clusters per tree for tiny white eggs that turn pink or red, entry holes, silk and dark droppings (Texas A&M; Oklahoma State).

When

Spring, just after pecan bloom: April in South Texas to early June farther north; later generations in summer.

Life cycle

Young caterpillars spend the winter in tiny silk cases near buds, then moths lay eggs on the nutlets just after pollination. There are 2 to 3 generations a year, and the first (spring) one does the most harm (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. Protect natural enemies Prevent

   Tiny parasitic wasps and flies attack the caterpillars, so avoid broad-spectrum sprays that kill them (Oklahoma State).

2. Bacillus thuringiensis (Bt) Natural enemies

   Spray Bt right as eggs hatch, before caterpillars bore into the nuts; rain and sun break it down fast, so timing is everything (Oklahoma State).

   Follow the label.

3. Spinosad Organic spray

   Spray at first egg hatch; once caterpillars are inside the nuts, sprays can't reach them (Texas A&M).

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

Plants it goes after

Pecan

Pressure by region

Oklahoma State gives its range as pecan country from Florida to southern New Mexico; the regional ratings are estimates based on that range and on where pecans grow.

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