Beneficial nematodes are
tiny, usually microscopic, roundworms that can be applied to control
caterpillars or grubs. Nematodes move within moist soil and enter
a suitable host. The nematodes, along with an associated bacteria,
kill the host within a few days.
to apply beneficial nematodes
- Select a nematode species that is most effective against the
target pest. Make sure you purchase nematodes from a reputable
- Apply when the caterpillar or grub stage of the pest is present
and active. This can be throughout the late spring and summer for
most pests. For white grubs, apply later in the summer or early fall
when more mature larvae are present and active. A second application
about 2 weeks after the first will enhance control.
- Do not apply if the soil temperature is below 60°F.
- Irrigate before application. The soil must be moist, but not soggy.
- Mix up a solution of fresh, infective stage nematodes in cool,
distilled water, pour the solution into a sprayer, and apply to the
- Apply nematodes in the evening, especially in hot areas. Nematodes
are killed by light and heat.
- Irrigate after application. Several irrigations may be needed to
keep the soil moist.
- Follow up a week or so after each application. Look for red or
yellow-brown infected larvae or pupae.