Application is simple. The mixture, including 

the medium is mixed with cool water and allowed to stand. After 30 minutes the mixture should be filtered through a fine kitchen strainer or piece of fine screen to separate the liquid from the vermiculite. The concentrate is mixed at the rate of one ounce to a gallon of cool water then applied with a hose-end or pump up sprayer. Some sources discuss applying either early in the morning or late in the afternoon. For maximum viability we recommend that you apply them at dusk. They are sensitive to uv light. Water the areas to be treated thoroughly. Concentrate the spray to areas where control is needed. Remember to apply to the soil, for most insects it is not necessary to spray foliage. Water again after application. It makes it easier for them to  travel and seek their hosts in a cool wet medium and washes them down onto the soil where they do the most good. 

    In the soil the worms begin the hunt. They are especially devastating to ants, flea larvae, grub worms, fungus gnats, mole, crickets, root knot nematodes, thrips , wireworms, and weevils.

    Fungus gnats are one of the most annoying and prolific of all insect pests. They are difficult to treat with anything but the most toxic pesticides and then not always effectively. Once they get started in a greenhouse the warm humid conditions are perfect for breeding. Water infected pots, concentrating on those that need to be kept moist, like cutting beds, with the nematode solution. They will destroy the larvae and end the infestation. 

    Fleas prefer to lay their eggs in loose soil where the emerging larvae can feed on organic matter. The larvae are blind and avoid sunlight. By spraying or drenching the most likely areas with the nematode solution the majority of the larvae will be infected and never reach the pupal or adult stage. 

    The Steinernemia feltiae has been discovered to be a very effective control for thrips. These destructive sucking insects are particularly damaging to roses. They prefer breeding in the soil around the base of plants and can also breed on the foliage or stems. The eggs are laid in a cut or break in the plant. For thrip control the foliage should be sprayed thoroughly. Keep the plants wet for at least 24-48 hours. If the nematodes are allowed to dry out they can die quickly especially in very warm weather.