Spiders, termites, cockroaches--household pests often have to be dealt with, and it is helpful to know what can be done. Any interested person is invited to a presentation on Tuesday, August 26^th at 10:00 a.m. in the Extension Building. Doug Jones, U of I Extension Integrated Pest Management Educator, will lead the discussion and provide informational materials. Please let us know if you would like to attend by calling 439-3178.

Control Fall Webworm Now

Control measures used immediately against fall webworms will be most effective while the caterpillars are still small and have not caused much damage, says David Robson, University of Illinois Extension horticulture educator, Springfield Center.

Fall webworm adults are white moths that lay eggs in mid-summer on the leaves of crabapple, black walnut, dogwood, birch, persimmon, white ash and many other trees. The eggs hatch into yellowish caterpillars or larvae in late July and spin a silk tent over several leaves.

As the caterpillars use up the food inside of the webbing, they make the tent larger to enclose more leaves. They seldom feed outside of the tent, although droppings are pushed out, which fall to the ground. When fully grown, the caterpillars are about an inch long.

In late August or early September, the caterpillars will form pupate or cocoons in debris under the tree. They spend the winter as pupae, and emerge as moths next summer. Since the caterpillars are later this year, expect them to feed into September.

Control should be done at this time of year while the caterpillars are still small. Clipping off any branches containing tents and larvae and destroying them is a good bet, but many feed up high making pruning difficult.

Infested trees can be sprayed with the organic insecticide Bacillus thuringiensis (Dipel, Thuricide). Several inorganic products are available. Check with your local Extension office or garden center for the best current recommendation. Remember to read and follow all label directions.

Control depends on the caterpillars enlarging the tent over treated leaves while the insecticide is still potent, since the insecticide spray does not penetrate the silk webbing.

Many birds feed on the fall webworm. Insect populations run in peaks depending on the predators the years before. It is possible to have significant damage then less and less for several years, followed by a gradual build-up again.

Also, damage by these insects does not usually result in the death of the tree because most food production by the leaves occurs in the spring and summer before the fall webworms hatch. However, trees might be weakened where other injury can affect the overall health of the plant.

Damage can be classified as aesthetic or visually bothersome causing a gardener to wonder if control is really necessary.