Webworms ugly but not lethal
RICKY THOMPSON

Half the trees in Jasper look like they are decorated for a Halloween fright night, festooned with spooky brown webs. It's not spiders, it's the so-called "fall webworm," Hyphantria cunea.

These inch-long green or yellow caterpillars, bristling with silky hairs, are actually moth larvae. In summer and early autumn they weave expansive webs that bind together the ends of branches. They eat every leaf within reach, continually building larger webs until late autumn, when they pupate.

Hyphantria cunea attack many kinds of trees, shrubs and vines. Pecan trees are their favorite, But they also like oak, hardwoods and fruit trees.

They look bad but they will not kill the tree. They can quickly consume vast quantities of leaves that are needed for fruit production, but they also bind up the ripening fruits and nuts in their webs. The only harm to the tree would be if they continue to strip the leaves year after year, preventing the tree from utilizing its leaves for photosynthesis.

What's worse, webworms seem impossible to fight. Their webs are often out of reach of conventional sprayers; commercial spray equipment can result in a rain of pesticide over large areas of your garden.

To plan an effective schedule of prevention and control, it helps to understand the life cycle of Hyphantria cunea. In spring, moths come fluttering up from cocoons carefully hidden in the bark of tree trunks and in ground debris. The adult moths are about 2 inches from wingtip to wingtip and are white spotted with brown. They lay eggs in clusters on the leaves of suitable host plants.

The eggs hatch within a week and out comes a tiny caterpillar. The first generation of the growing season, they spin webs and eat leaves. This first infestation is so mild that sometimes the webs go unnoticed.

When the first-generation caterpillars have eaten their fill by early summer, they form cocoons and pupate, usually in the bark, of a tree or underneath leaves or debris on the ground.

By midsummer they reemerge as moths. A second generation follows -- this time larger and more destructive. That's what we are seeing now.

Because the webworms -- in one form or another -- are present year-around, it's possible to devise a yearround strategy for dealing with this pest. Here are some tactics that will help reduce the amount of webworms you have to deal with: 3 In winter or early spring, remove fallen leaves, ground debris and mulch, which may harbor pupae. Replace with fresh, pest-free mulch. 3 Inspect susceptible plants for greenish egg masses, which are typically laid on the undersides of leaves and protected by a woolly or scaly covering. Eggs are deposited from late spring through fall. Remove any affected leaves and destroy them. This strategy requires time and sharp eyes and is obviously impractical for tall trees. 3 When you see webs, clip the infested branches and burn them, or drown the larvae in a bucket of soapy water. A pole pruner with a lopper blade will help you reach webs within 16 feet or so of the ground.

Ricky Thompson, the Texas Cooperative Extension agriculture agent, can be reached at 384-3721.