How to Manage Pests

Pests in Gardens and Landscapes

Insect parasitic nematodes


Biological control (not a registered pesticide).

Plant uses

Ornamentals, fruit trees, vegetables.

Pests controlled

Nematodes control insects that feed in protected, moist areas such as turf, soil, or within tunnels of tree trunks and branches. These include the soil-dwelling larvae of weevils such as the black vine weevil, soil dwelling cutworms or grubs, and clearwing borer or carpenterworms larvae in trees.

LowHazards to people

Extremely safe.

LowHazards to wildlife

Very low toxicity to vertebrates.

LowHazards to beneficials

Generally low, but may attack larvae of some related beneficial insects in soil. Commercial species do not injure earthworms.

Potential period of activity after treatment

Parasitic nematodes will be killed within several hours if exposed to direct sunlight. Under the soil or in other protected dark, moist areas, the nematodes may remain viable for several days.

Precautions and safety equipment

There is no need for masks or specialized safety equipment. Nematodes are exempt from U.S. EPA registration and can be used almost everywhere (Hawaii is an exception). Because they leave no residues, application can be made anytime before a harvest or on any crop.

Active ingredient

Several parasitic nematode species are commercially available. The most common ones are Steinernema carpocapsae for insects that are mobile above the soil surface such as cutworms or borers such as clearwing moths or artichoke plume moth. Heterorhabditis bacteriophora are cruisers that actively search for insect larvae deeper in the soil profile such as root weevils and grubs, but are also effective against clearwing moths. These two nematodes differ in storability. Heterorhabditis is best used within days of being obtained fresh by mail order from a producer. Steinernema carpocapsae can be stored for several months in a cool, dry location away from sunlight.

Application tips

Always check the label before purchasing or applying a pesticide product for a specific pest on a specific plant to be sure it can be applied. Follow label directions precisely.


Statewide IPM Program, Agriculture and Natural Resources, University of California
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