Includes nightcrawler (Lumbricus terrestris)

Pest description and crop damage Earthworm bodies are long and worm-like, usually from one to six inches long. The body is segmented. Earthworms are beneficial in soil for aeration, water penetration, thatch control, addition of bacteria, organic matter and other benefits. Earthworm castings are composed of soil and plant residue and are very effective at improving soil structure. Although earthworms are generally considered beneficial, on rare occasions and in rare situations, earthworms may become undesirable. Their burrowing activity and cast deposition can cause damage to new seedlings or roughen established turf areas.

Biology and life history Earthworms are mainly free-living terrestrial worms. They are found in soil, leaf litter and under stones and logs, usually in wetter, more heavily vegetated regions. Earthworms move along by extending the front end of the body, taking hold of the substrate using bristles on their body, then drawing up the rear end. Earthworms don't have lungs, but instead breathe through the skin. In order to breathe this way, the skin must be kept moist. Earthworms do this by excreting mucous and body fluids onto the skin. This need for moisture restricts their activities to a burrowing life in damp soil. They emerge only at night when temperatures are cooler, and retreat deep underground during hot, dry weather. Most earthworms are scavengers that feed on dead organic debris, including leaves. Soil consumed by worms is deposited on the surface of the ground, in the form of 'castings.' All earthworms are hermaphrodites (that is, a single individual can produce both male and female gametes, the eggs and sperm). Eggs are produced when two earthworms inseminate each other during mating. Mating occurs usually when the ground is wet following rain. Egg cocoons are deposited in the soil. The fertilized eggs develop directly into young worms. The juveniles grow continuously until they reach adult size.

Management-biological control

Birds can often assist in control since they will pluck them from the turf, although this in itself may be damaging to turf.

Management-cultural control

There is no treatment threshold for earthworms: the threshold is determined by the tolerance level of the homeowner or turf caretaker. Power raking or rolling of the turf when castings are soft will usually even the soil. Grass clippings can be collected, if desired, to remove some of the food source. This, however, also reduces the return of organic matter and nutrients to the soil.

Management-chemical control: HOME USE

There are no pesticides registered for earthworm control.

Management-chemical control: COMMERCIAL USE

There are no pesticides registered for earthworm control.