Scanmask Spray

For most pests, and for a general or preventative treatment, you can apply Scanmask anytime the soil is not frozen. Some pests have a best window; for example, cabbage root maggots are treated from March to June, when you plant, and white grubs from March to June or August to September. The treatment calendar lists the timing for each pest.

The nematodes in Scanmask stay active in soil as cool as about 55°F (that's the soil temperature, which can differ from the air temperature), so Scanmask works well in early spring and fall.

Apply in the late afternoon or evening. Sunlight and heat harm nematodes, so avoid the middle of the day.

Scanmask can be applied with the Nema-Jet Sprayer or a hose-end sprayer, a pump or backpack sprayer, or a watering can.

1. Apply in the evening, out of direct sunlight.
2. Water the area to be treated.
3. Mix the nematodes thoroughly with clean, cold water for your application method (below). Let the mixture sit for 20 minutes, then mix it again right before you apply.
   • Watering can: mix 4 gallons of water per 5 million nematodes. Add it to the watering can and apply 1 gallon per 50 sq ft.
   • Nema-Jet or hose-end sprayer: mix ⅓ cup of water per 5 million nematodes. Add it to the sprayer bottle, set the sprayer to ON (or its highest dilution setting), and apply 1 cup per 600 sq ft.
   • Pump or backpack sprayer: mix 1 gallon of water per 5 million nematodes. Remove any filters 50 mesh or finer, add the mixture to the sprayer, and apply 1 gallon per 200 sq ft.
4. Water the area again to wash the nematodes off the leaves and into the soil.

5 million nematodes is about 1 packed teaspoon.

See How to apply for the full directions for each method.

Put the package in the refrigerator right away, and use it before the date on the package. Never put it in the freezer. The cold packs in the box don't need to still be cold when it arrives. See Shipping and arrival.

The nematodes in Scanmask occur naturally in soil and haven't been modified in any way. They are harmless to people, pets, and plants, and the US Environmental Protection Agency (EPA) has exempted them from the registration required for chemical pesticides. The carrier they come in isn't meant to be eaten and may upset the stomach, so keep the package away from children.

Scanmask works alongside many common herbicides, insecticides, fungicides, and other biological controls, but some need to be applied a week or two apart; see the chemical compatibility list on our How to apply page.

Scanmask. It kills the widest range of pests, so it's our recommendation when you're treating several pests, aren't sure what the pest is, or want to prevent problems. See Which nematode do I need?

Yes. The nematodes in Scanmask stay active in soil as cool as about 55°F, so it's a good choice for early spring and fall. See When to apply.

Yes. Beneficial nematodes don't harm people, pets, plants, or beneficial creatures like bees, earthworms, and ladybugs. The EPA exempts them from pesticide registration.