Fall Webworms

The Fall Webworm (Hyphantria cunea) is a widely distributed native pest of shade trees and shrubs and appears from late summer through early fall. It feeds on almost 90 species of deciduous trees commonly attacking hickory, walnut, birch, cherry, and crabapple. This species acts similarly to the eastern tent caterpillar, but the fall webworm constructs its nest over the end of the branch rather than at tree crotches. The large conspicuous webs contain caterpillars, dead partially eaten leaves, and fecal droppings.

The larvae eat the best part of the leaf, leaving the veins and build unsightly webs on the outer most tips of branches.

 

Fall Webworms winter over as pupae.

In the spring the adults emerge, mate and deposit eggs. The female will lay up to 600 eggs, these soon hatch out into larvae.  Adults are a white moth, sometimes with markings on the wings.

Two forms of larvae exist:

Black-headed larvae
These hatch out earlier in the season and are more common

Red-headed larvae These hatch out a little later and prefer pecan trees.

The larvae go through several molts before falling to the ground to pupate.  The egg-to-adult cycle is complete in as little as 50 days.  In the north there will be 2 generations per year and up to 4 in the south.

    

Fall Webworm Control

When trying to control Fall Webworms it is important to get the chemical you use into contact with either the worms themselves or on the leaves they are feeding on.  Many times this is difficult because the larvae are protected by the webs they create.  To help with this, the addition of Hi-Yield Spreader Sticker is almost mandatory.  Spreader Sticker will help to penetrate the sticky web and help it stick to the leaf for a longer lasting residue.

Natural Guard brand by ferti•lome Spinosad is the BEST choice of product for Fall Webworms.  This is an OMRI Listed natural wormicide that is translaminar so it will last the longest and is very low impact on beneficial insects.

Natural Guard by ferti•lome Caterpillar Killer Spray with Bt is another wormicide that is natural. This product contains Bt, a living bacteria. The downfall of Caterpillar Killer Spray with Bt is the residue is measured in hours so you have to repeat more often.

For hard chemistry, Hi-Yield Bug Blaster will leave the longest residue and offers something a little more broad spectrum.Save

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When trying to control Fall Webworm it is important to get the chemical you use into contact with either the worms themselves or on the leaves they are feeding on. Many times this is difficult because the larvae are protected by the webs they create. To help with this, the addition of Hi-Yield® Spreader Sticker is essential. Hi-Yield® Spreader Sticker will help to penetrate the sticky web and help it stick to the leaf for a longer lasting residue.