After you figure out what type of insect pest is creating problems for your grass, you have many treatment choices, including ones that don’t rely on strong insecticides and have a low impact on the environment. Don’t forget — lawns are where kids play and where birds feed. Lawns should be safe places to be.
Following are some choices for controlling lawn insects:
Alter cultural practices. A healthy vigorous lawn has fewer problems. You can often reduce chinch bugs by watering more efficiently. Many insects are more troublesome in lawns that have a thick layer of thatch, so aerate your lawn.
Plant resistant lawn grasses. If a particular insect gives you problems over and over again, find a grass that’s better-adapted to your climate.
Use biological controls. You can choose from several useful biological-control methods for controlling lawn insects.
All those mentioned here are harmless to humans and pets:
Predatory nematodes. These microscopic worms attack the soil-dwelling larvae of several common lawn pests, including Japanese beetles, mole crickets, sod webworm, and cut worms. You simply mix the nematodes with water, sprinkle them on a moist lawn, and let them do their stuff.
Bacillus thuringiensis. Also known as Bt, this bacterium attacks the larvae of moths and butterflies and can control sod webworms and similar pests. Another form of bacillus, called milky spore, is effective against the larvae of Japanese beetles (white grubs.
Endophytes. These microscopic fungi grow inside the blades and leaf stalks of grasses. Endophytes are harmless to humans but toxic to many lawn pests, including sod webworms, chinch bugs, and billbugs.
Use botanical insecticides.
These insecticides, derived from plants, break down quickly and are relatively nontoxic to mammals, including humans:
Neem comes from the tropical tree Azadirachta indica. This insecticide kills young feeding insects, including aphids. (Greenbugs, a lawn pest in the midwestern United States, are aphids.) Neem also repels Japanese beetles, which may prevent the beetles from visiting your lawn, laying eggs, and giving you a white grub problem.
Pyrethrin derives from the daisy, Chrysanthemum cinerariifolium. Pyrethrin is a broad-spectrum insecticide, which means it kills a wide range of insects — both good and bad. However, this insecticide is useful for spot-treating areas of the lawn infested with sod webworms or white grubs (the larvae of scarab beetles).
Use insecticidal soaps. Derived from the salts of fatty acids, insecticidal soaps kill mostly soft-bodied pests, including chinch bugs, sod webworms, and grubs (the larvae of scarab beetles). The soaps work fast, break down quickly, and are nontoxic to humans. Insecticidal soaps are most effective when mixed with soft water. When controlling soil-dwelling insects you must apply the soap with enough water to soak the soil to a depth of 6 inches.
Use traditional insecticides. Many traditional insecticides, including carbaryl (sold as Sevin), diazinon, and chlorpyrifos (sold as Dursban) are labeled for controlling insects on lawns. In some situations, using them may be your only choice for quick and effective control of a particularly tough problem.
Use traditional insecticides only as a last resort. Using these chemicals can have a negative impact on your lawn, killing beneficial organisms that live there, including ones that normally break down thatch. Don’t forget, treating a lawn is not like treating one sick shrub. You usually have to treat a large area and use a significant amount of insecticide. Remember, too, the other creatures — kids, birds, bees, and pets — that visit your lawn. For example, caretakers can no longer use diazinon on golf courses because of the negative impact it had on bird life.
No matter which pesticide (insecticides, fungicides, herbicides, and other products used to control pests of plants) you decide to use, you must use it safely. Even pesticides that have a relatively low impact on your garden environment can be dangerous to use and toxic to humans.
Follow these safety tips when working with insecticides:
Always follow instructions on the product label exactly. Doing otherwise is dangerous and against the law.
Wear rubber gloves when mixing and spraying pesticides. Many of these chemicals can be absorbed through the skin.
Spray when winds are calm.
Don’t spray if you expect rain — the excess water may wash the chemicals into storm gutters and storm drains.
Store chemicals in properly labeled containers — locked and out of the reach of children.
Dispose of empty pesticide containers as described on the label or contact your local waste disposal company for appropriate disposal sites.
