Beneficial Nematodes


  • eat various plant predators, such as:
    • Army worms
    • borers
    • cucumber beetles
    • cutworms
    • gypsy moths
    • Japanese beetles (white grubs)
    • root maggots
    • root weevils
    • wireworms
    • see specific species for their target prey
  • beneficial nematodes are totally safe to use: they are not harmful to humans, pets, plants, birds, earthworms, honeybees, or beneficial insects
  • the way they are effective against plant predators differs by species and by target. examples are:
    • N. carpocapsae juvenile-stage injects the target insect with bacteria that kill it within 24 hours
  • they are self-limiting (die out when they’ve cleared out the pests)

Species available

Where to Buy

How to Use Beneficial Nematodes

All of the species that I’ve worked with come in a dry medium that disperses in water, which then gets sprayed on the soil or foliage. They sell them in quantities sufficient to treat a defined amount of area. Comparing the different brands will show differing numbers of actual nematodes to treat the same treatment area. More is most likely better in this case, so opt for the brand that has the most nematodes for the price.

  1. Refrigerate
    • When you receive your beneficial nematodes, refrigerate them until ready to use.
    • Do not freeze.
  2. Divide
    • When you are ready to make your first application, divide them up into the number of applications you plan to treat your garden with – typically 2 or 3 – and put all but one back into the refrigerator.
    • I use little plastic disposable containers for this.
  3. Wet Treatment Area
    • using the hose-end sprayer you are going to use to spray the nematodes, to wet the ground or foliage to be treated
    • Helpful hint: if your hose end sprayer is not adjustable, put something that colors the water (food coloring, kelp extract, etc) in the sprayer to determine how much area your hose-end sprayer covers with one batch. This will tell you how many batches it will take to do the complete application.
  4. Mix Treatment
    • Once all of the ground to be treated is wet, you are ready to mix your beneficial nematode treatment.
    • Put the following into your hose-end sprayer tank:
      • beneficial nematodes
        • take the amount set aside for one application and divide it into the number of batches it will take to cover the area to be treated
        • put the amount for the first batch in to the tank
      • optional: fertilizers/amendments needed for your garden
        • kelp extract
        • fish emulsion
        • molasses (feeds the microorganisms)
        • calcium
      • water: fill the vessel with water, making sure everything gets dissolved or dispersed evenly. 
      • The mix should sit for about 5 minutes before spraying, so everything is well-hydrated and dispersed.
  5.  Spray!
    • Adjust sprayer to spread your mix evenly over the entire area to be treated
    • I’m having trouble determining what this is with my Chameleon sprayer because I think it’s broken or clogging…I just ordered a new one from Ortho because of the negative reviews for the Chameleon on Amazon.
  • in compost:


  • when not in use, store in the refrigerator
  • limited shelf-life, so buy only enough to use within the stated shelf-life (per supplier, per species)
  • do not freeze


  • The Kitchen Garden: pp 277, 349-351
  • The Gardener’s A-Z Guide to Growing Organic Food: p316


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