Predatory nematodes can be applied in the spring to combat chafer beetles, wireworm, and other soil dwelling beetle larvae. Predatory nematodes are effective against over 250 species of insect pests. Only insects that have a soil dwelling stage (egg, larvae, pupae or adult) can be controlled by nematodes. Therefore, the nematodes are best used as a preventative. In field crops they infect cutworms, grubs, root borer larvae, root weevil larvae, flea beetle larvae, carrot rust fly larvae, and other pests. Parasitic nematodes invade and destroy white grubs, pill bugs eggs & larvae, Japanese beetle larvae, crane fly larvae, and other insect pests commonly found in lawns and turf.

Contents: 5 milllion Heterorhabditis bacteriophora

Storage: The nematodes in the little box are alive and can be stored for 3 weeks at a storage temperature of 8-12 degrees Celsius in the dark until conditions are right to apply them. Do not freeze this package. Avoid exposing the nematodes to bright sun or hot temperatures.

How they work: Beneficial (or predatory) nematodes are naturally occurring organisms and are not harmful to humans, pets, wildlife, birds, soil, earthworms, water sources, or the atmosphere. They are safe and legal to use on all crops in Canada. The nematodes migrate through the soil, finding insect larvae by detecting either a slight increase in temperature or a release of methane gas. The microscopic infective juveniles enter the larvae and multiply and release bacteria that eventually kill the host. The nematodes feed on the bacteria and the decomposing host tissue where they reproduce until numbers drive them out to find a new host. 

The nematodes in the little bag are species that are known to do well in cooler soils. They survive over a wide temperature range and reproduce within 10 days.


Apply in early spring (after air temperatures are about 9-10 C) or late summer or fall when temperature is moderate. It is best to apply on an overcast day or very early in the morning or in late evening. Never release them onto hot dry ground or ground which is flooded. As a rule of thumb, “If an earthworm can survive, a nematode will also”. Try to time application no more than 3 months before the pest is active in the soil. Water soil thoroughly before applying the nematodes or if it is raining, water after applying the nematodes.

Place contents of the bag into a container of room temperature water and agitate to rinse out the pouch thoroughly. If only tap water is available, let it sit in a bucket for several hours or overnight so the chlorine will disperse. Slosh the bag about several times, dispersing the nematodes into the water. You now have a concentrate. You will further dilute the concentrate before applying it to soil. You must apply the nematodes within 2 hours of making up the concentrate.

To apply, use a watering can, bucket or sprayer (that is not equipped with a superfine sand filter). The nematodes can withstand pressure up to 300 psi. Keep the water agitated to ensure even coverage.

After application, moisten the area again with more water (turn on a sprinkler) to carry the nematodes into the soil.

To determine how to dilute the concentrate:

Wet the application area with plain water using a watering can or sprayer and record how much water was needed. Then dilute the concentrated nematode solution to provide the amount of solution that it took to cover the area. For example, if it took 5 full watering cans of water to cover the area — you would divide the concentrated nematode solution into 5 equal parts and add one part to each of the next 5 cans. If it took 2 full sprayers to cover the area with plain water, you would divide the nematode solution in 2 parts and add one part to each sprayer of water.

Water out to the drip line of rhododendrons, along the rows of vegetables, or cover the lawn completely.


The strains supplied by West Coast Seeds are very vigorous, reproduce rapidly and have strong searching and quick killing ability. These potent, high-quality strains are the result of several hundred generations reared for these characteristics and thus fewer numbers of the nematodes are required to cover a selected area.

The five million nematodes prepared in the one gallon of water will cover an area of 230m2 (2,500 square feet).

An application in spring, another in fall followed by another spring application should build up an active population in your soil that will be self-sustaining, only requiring a boost in 3 years.

Nematode Biology

Entomopathogenic nematodes, or EPNs, are very small worm-like organisms that make their living killing insects. The nematodes do not act alone to kill insects rather they merely serve as a delivery service for the actual organism that kills the insect, a bacteria.

Here’s how the process works: The “infective juvenile” stage locates a host insect, usually an immature form (larva or pupa) in or on the soil, and then it enters the insect through the mouth, anus, or breathing tube. Once inside the insect, the nematode releases the bacteria from its gut, and the bacteria starts growing, ultimately killing the insect. While this is going on, the nematode is feeding on the bacteria and what was once the insect. The nematode is also continuing to grow and develop to an adult, ultimately going through one or more generations (usually 2-3) inside the carcass of the insect. Once the bacteria and nematodes use up all the nutrients in the host insect, more infective juveniles (ijs) are produced which load up on the bacteria then emerge from the now long-dead insect and continue the cycle. Two important points to remember though, is that the only free-living form of the nematode is the infective juvenile, and that the bacteria is usually found only with the nematode and/or the insect it killed.

Pests Nematodes Control

Heterorhabditis bacteriophora are effective against: 

  • Beetles (Coleoptera):
    • Weevils (Curculionidae): Black vine weevil (Otiorhynchus sulcatus) and other Otiorhynchus spp.
    • White grubs (Scarabaeidae): European chafer (Amphimallon majale); Summer chafer/ June beetle (Amphimallon solstitialis); Amphimallon aestivus; Common cockchafer (Melolontha melolontha); Common garden chafer (Phyllopertha horticola); Phyllophaga spp.; Welsh chafer (Hoplia philanthus) and other Hoplia spp.; Japanese beetle (Popilia japonica); Oriental beetle (Anomala orientalis); Asiatic garden beetle (Autoserica castanea); Dune chafer (Anomala dubia); Brown chafer (Serica brunnea); Anoxia villosa
    • Dung beetles (Aphodius spp.)
    • Leaf beetles (Chrysomelidae): Flea beetles (Phyllotreta spp.)
  • Caterpillars (Lepidoptera):
    • Common swift moth (Korscheltellus lupulina)
  • Other:
    • Wireworms
    • Fungus gnats