Have you been bothered by crows and raccoons digging holes in your lawn? What about patchy grass, grass that peels away from the soil if pulled, or even little white grubs just below your soil? You might have a problem that beneficial nematodes can fix! Nematodes are microscopic worms that live in the soil.  Beneficial nematode species attack pest insects by entering their bodies and releasing a fast acting insect-killing bacterium. Nematodes are safe to use around kids, pets, and edible crops, and are low impact on the environment.

Common Beneficial Nematode Species

Heterohabditis bacteriophora: for use to control white grubs, black vine weevils, and more

White grubs are the larval stage of a variety of beetles, including June Bugs, European Chafer Beetles, and Japanese Beetles. Grubs are cream-coloured, grow up to 1.5cm (0.6”) in length, have distinctive legs and heads, and are found in the root systems of plants and lawns. June bugs have a 3-year life cycle. Adults overwinter in the soil and emerge to lay eggs in late May to early June. After eggs are laid, the white grubs will hatch and begin to feed on grass roots. They then lay dormant deep in the soil through the fall and winter before moving back to the surface in spring to continue to feed. In the fall, they again go deep into the soil for the winter before returning to the surface the following spring. At that time, the grubs feed for only a few weeks before pupating and emerging as adult beetles. The beetles remain inactive in the soil until the next spring before taking flight to reproduce. The life cycle is then complete and a new generation is started. The second year grub stage is the most damaging due to the size and appetite of the grubs. Effective between 12°C and 30°C

We recommend applying white grub control nematodes in the spring, late summer, and early fall.  Ensure your lawn is thoroughly watered before and after application, as nematodes need water to move through the soil and reach the root system of your grass. Keep your lawn well-watered for at least two weeks following application.

Steinernema feltiae: for use to control leatherjackets, fungus gnats, some thrips, grubs, and more

Leatherjackets are the larval stage of the crane fly. The larvae are about 2.5cm (1” long), greyish black in colour, legless and with no distinct head. During summer, leatherjackets can be seen in the soil. In late August, the adult crane flies emerge from the soil and begin to lay eggs. Within about two weeks, the eggs hatch into leatherjackets and will proceed to overwinter in the soil. In spring, the larvae reemerge and feed on grass roots. In June the leatherjackets stop feeding and pupate in the soil until fall when they emerge as adults, mate and lay eggs, completing their life cycle. Late summer gardeners may see clouds of adult crane flies emerging from lawns in the early morning. This is a sign that within a few days the adult flies will begin laying eggs.

For most effective control, apply nematodes when the young leatherjackets are active in the soil in late summer and early fall. Ensure your lawn is thoroughly watered before and after application, as nematodes need water to move through the soil and reach the root system of your grass. Keep your lawn well-watered for at least two weeks following application. Effective between 10°C and 30°C.

Steinernema carpocapsae: for use to control cutworms, webworms and other caterpillars, some grubs and flies, and more

Most caterpillars have a relatively short life cycle, from one month to one year in length. After hatching, they have voracious appetites and can cause a large amount of damage to crops and gardens in a short period of time. Some species bore into fruit and stems, making them particularly destructive and hard to detect. It’s important to act quickly when an infestation of cutworms, webworms, or other caterpillars is active.

For most effective control, apply nematodes to the soil and/or foliage at first sight of pests. Ensure the soil is thoroughly watered before and after application, as nematodes need water to travel. Keep your soil well-watered for at least two weeks following application. Effective between 12°C and 30°C.

Tips for Success with Beneficial Nematodes

The area to be treated must be moist prior to application. Water thoroughly with a hose or sprinkler or apply your nematodes after heavy rain. Keep your soil moist for at least two weeks after application.

Refrain from applying your nematodes in direct sunlight. Apply in the evening or on an overcast day. Check the soil temperature in your area and only apply when within the effective range for your nematodes.

Use your nematodes as soon as possible, ideally immediately after purchase. If needed, store your nematodes in the fridge until use. Note the expiry date listed on the package and use your nematodes before this date. Apply the entire package at once immediately after mixing.

If using a sprayer to apply your nematodes, make sure it has been cleaned and rinsed well and remove any screen or filter 50 mesh or finer. Do not mix nematodes in a sprayer that has previously held pesticides.

Application Directions for Beneficial Nematodes

Water your soil thoroughly before applying your nematodes. Add the contents of your package to the reservoir of your sprayer and mix with lukewarm water. Spray the mixture directly on to the affected areas of your lawn or garden. Keep the soil well-watered for at least two weeks following application.