Insecticide For Earthworms

Earthworms have both male and female reproductive organs so any two adult earthworms can mate, which takes place on or just below the soil surface at night. Mated earthworms deposit fertilized eggs in cocoons in the soil. Each cocoon contains approximately four eggs that hatch in two to three weeks.

In addition to castings / mounds disrupting the turf surface, they can also accumulate on or disrupt the path of maintenance equipment, interfering with turf input applications and mowing. Earthworms are also a major food source for moles and cluster flies and can attract these pests into an area. Extremely high populations of earthworms may also disrupt the turfgrass root system.

Cultural Control

Earthworms generally prefer less-acidic (pH<6.0), less well-drained soils so increasing the pH and regulating soil moisture can reduce the incidence of earthworm infestations. Excess organic material, such as grass clippings, should be collected and removed from the turf surface. Sand topdressing is a method employed by some turf managers to manage earthworm castings but with varying results. An organic fertilizer product (Ocean Organics’ Early Bird Fertilizer) created from crushed tea seed pellets contains saponins that may disrupt the mucous surface of earthworms.

Biological Control

Earthworms have some natural enemies including: ants, centipedes, birds, snakes, carabid beetles and nematodes.

Chemical Control

There are no chemical pesticides for homeowners registered for treatment against earthworms. Of the turf pesticides labeled for other insect pests, and are still commonly used, carbaryl (Sevin) and imidacloprid (Merit) are toxic to earthworms.