Establish Natural Defenses
A good anti-pest defense involves building up the soil in the yard with organic matter. Mulching is the easiest way to add organic matter. As the mulch slowly breaks down, earthworms hasten this process by pulling the materials down into their tunnels, thereby adding vital nutrients and improving soil structure and drainage. This natural process provides longterm help to trees and shrubs stressed by defoliation by gypsy moths. Spread a thick layer of organic material of some kind on the ground around each tree or shrub all the way out to the dripline (the furthest extent to which the branches extend). The very best mulches are composted municipal sludge, mushroom compost, leaf mold, or commercial compost .[752 700] Next best is chopped leaves. Grass clippings are not satisfactory, because they tend to form a mat that resists water penetration. Bark_mulch [750 300] is long-lasting, but adds little to the soil around tree roots.
Tip: If the yard is well wooded or if it abuts forest land, try to keep the forest floor as natural as possible. Because many trees, such as oaks, thrive in acid soils, take care to leave the acid-rich leaf litter in place wherever practical. This layer of natural plant material protects the tree’s feeder roots from drying out and provides a home for many beneficial insect and animal predators.
Besides building a rich soil base, it is a good idea to encourage the many insects and animals that normally prey on gypsy moths. These natural predators come in all shapes and sizes. While many are insects themselves, others are microscopic organisms, small animals such as white-footed mice, shrews, chipmunks, voles, squirrels, and birds. The more of these different kinds of predators live in your yard, the fewer pest insect problems you will have. They will take up residence in a yard that includes their favorite plants and other foods. The greater the variety of plants on your property, the greater will be the variety of natural enemies of gypsy moths that will be attracted to it.
Keep Trees And Shrubs Vigorous
Healthy trees are less likely to suffer from gypsy moths than unhealthy trees, except during major outbreaks. Anything you do to improve your trees’ health will reduce damage from gypsy moths in the years to come. Give some thought to the affected plants’ situation. Make an effort to improve vigor by watering during dry periods over the summer and fertilizing in the fall, if appropriate. Prune any injured or broken branches or stems cleanly and carefully. Apply mulch to discourage weeds, hold soil moisture, and improve the health of the soil beneath.
Clean The Yard In The Fall
Gypsy moths lay their eggs just about anywhere: on lawn furniture, stone walls, woodpiles, fences, garages, and outbuildings. In the fall, check all these spots for masses of eggs and remove and destroy any that you find by scraping them into a can of kerosene, gasoline, or water, or by burning them. Eggs, larvae, and pupae can also be found in plant debris, so a good fall cleanup will help to prevent the return of gypsy moths next year.
Attract Beneficial Insects To The Yard
Spiders and predator insects will kill many more gypsy moth caterpillars than a yardener armed with an insecticide ever will. If you don't use broad-spectrum insecticides, you should have lots of beneficial insects such as assassin bugs, ground beetles, soldier beetles, tachinid flies, ants, harvestmen (“daddy-long-legs”), paper wasps, and tiny chalcid and trichogramma wasps that parasitize the eggs. If you do not have very many beneficial insects already, introduce some into your home landscape to patrol for gypsy moth caterpillars. Many kinds of beneficial insects are available from mail-order suppliers. Properly introduced into the yard, they will search out and feed on the caterpillars and on other pests as well.
Feed and House Beneficial Bugs
Encourage the natural predators of gypsy moths to stay in your yard by providing them with a tempting variety of their favorite plant sources of pollen and nectar. One product, a wildflower mix called Border Patrol, is a mix of insectary_plant_seeds particularly attractive to beneficial insects, and includes evening primrose (Primula), wild buckwheat (Eriogonum), candytuft (Iberis), baby blue-eyes (Nemophila Menziesii), bishops flower, black-eyed Susan (Rudbeckia hirta), strawflowers, nasturtiums (Tropaeolium), angelica, and yarrow (Achillea).
Wasp House Trick: Paper wasps hunt gypsy moth caterpillars to provide food for their young. They will nest in your yard if you provide adequate shelter. Build some small boxes, about 6 inches square, and leave them open at the bottom. Paint them brown or black and fasten them to stakes placed in sunny areas. The wasps will build nests inside the boxes.
Support Birds All Year Round
Winter songbirds eagerly probe the bark of trees and gobble up as many gypsy moth eggs as they can find. Among the most helpful egg hunters are chickadees, nuthatches, and tufted titmice. Birds that eat gypsy moth caterpillars include bluebirds, blue jays, catbirds, chipping sparrows, cowbirds, crows, cuckoos, grackles, orioles, red-winged blackbirds, robins, starlings, towhees, and vireos. Encourage bird allies to take up permanent residence in the area by putting out seed and other foods such as suet_cake in a suet_cage for them. In the spring and summer reduce the amount of bird food you have in your bird_feeders, but keep setting out snacks during this time to encourage more bird families to live in your yard.