Beneficial nematodes (Steinernema feltiae) are microscopic roundworms which prey on soil and wood-boring pests, such as flea larvae, white grubs, cutworms, strawberry weevils, cabbage root maggots, and fungus gnat larvae. They act by penetrating pest hosts and in conjunction with bacteria they carry, kill most hosts within several days. Steinernema complete their lifecycle in the host’s body, which culminates in the emergence of juvenile nematodes. The entire cycle takes between seven to 14 days. This particular species of nematode is not harmful to humans, gophers, domestic animals, earthworms, ladybugs, lacewings, or praying mantis.
Beneficial nematodes (BN) may be released any time of the year when the soil temperatures are 60° F or above. In the Bay Area, release from March to November is safe. Beneficial nematodes thrive in moist soil conditions, but will not withstand soggy soils. They also cannot withstand direct sunlight, so must be applied after sundown or in shaded areas. Populations remain effective for up to two years, but annual application is recommended for maximum efficacy.
Each package contains seven million beneficial nematodes and covers up to 2500 square feet. Faster results occur with higher concentrations.
Water the areas to be treated, thoroughly, the day before spreading the beneficial nematodes. Beneficial nematodes sold as Nema™ Globe nematodes appear as a very fine light brown powder packaged in a Ziploc bag. This package contains about seven million beneficial nematodes and covers up to 2500 square feet. Fill a one quart jar three-quarters full with warm water. Pour the beneficial nematodes powder into the jar of water, and rinse the Ziploc package and any remaining powder into the jar of water. Vigorously shake the jar with its beneficial nematodes powder and let stand for a one-half hour or until the contents have dissolved. Break apart any large clumps to help them dissolve. After the powder has dissolved vigorously shake the solution again and pour the contents into a one and one-half to two gallon watering can half filled with lukewarm water. Add enough water to fill the watering can, using the added water to rinse the one quart jar. Stir the beneficial nematodes solution in the watering can frequently to keep the beneficial nematodes suspended. Distribute the beneficial nematodes solution directly from the watering can or pour the solution into a tank sprayer and spray the solution over the affected area. Use a slightly coarse spray and a strong pressure. Agitate the container frequently to keep the beneficial nematodes suspended. Keep the lawn moist for the next three days (or a week in dry weather) to ensure nematodes are flushed down into the root zone where feeding grubs are present.