These Steinernema feltiae nematodes are microscopic larvae that target fungus gnats larvae in the soil. They parasitize the bodies of their prey and kill them within a few days by feeding on their tissues. The predator reproduces in the body of its host and new nematodes are released.This product contains four yellow sticky traps and four treatments to be diluted and sprayed on the soil. The two sizes allow for treating up to 60 or 120 plants per treatment. The quantities are approximate and are based on medium-sized plants in 8-inch pots. Adjust as needed.