Things You'll Need
Look for the type of beneficial nematode for your situation. There are two families of nematodes that kill harmful insects. The Steinernematidae carpocapsae species works best on vegetable crops to rid it of cutworms, root maggots and armyworms. It's also good for cranberry root weevils and girdlers. It kills borers of ornamental plants and mint. The Heterorhabditidae bacteriophora kills berry root weevils and rootworms, scarabs and billbugs.
Purchase from a reputable dealer. Since the beneficial nematodes are tiny, clear and come in multiples of 1 million, it makes it difficult to know if you received your full shipment. Unless you have a microscope and a lot of time to count, order only from a company that you trust, or a local vendor.
Select the amount you need. While each company recommends varying amounts, many scientists agree that a minimum of 1 million per acre is
a good start. Each species of nematode requires different numbers to be effective.
Ship them overnight when you're available to receive the package. If the weather is hot, sitting at an overnight terminal or on your porch isn't an option for your beneficial nematodes. When you buy beneficial nematodes, make sure the overnight package comes on a day you are home.
Expect to see slow changes. The beneficial nematodes work effectively but it takes them a bit of time to poison all the plant predators. Don't give up hope, and look for reduction of damage.
Prepare ahead and have a spray bottle that attaches to your hose. These tiny creatures need to be applied in the early morning or evening as soon as they arrive. Store them in the refrigerator if you can't put them on the soil right away. Mix the beneficial nematodes in water and spray on the soil.