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How to Kill Nightcrawlers

By Elizabeth Knoll
Nightcrawlers are beneficial to the soil, though they can also cause problems such as extreme mounding.

Nightcrawlers can be beneficial to your yard. The tunnels they make in soil act as natural aeration channels. The worms also break down the mulch on the surface of your soil and spread it as far down as 12 inches. However, they also cause your soil to mound: the more nightcrawlers you have, the worse the mounding can get. There are no insecticides specifically formulated to kill nightcrawlers, so any chemicals used to kill them will also kill other beneficial microorganisms. It is best to use these chemicals sparingly.

Read the directions on the back of your insecticide. Some insecticides come in a powder form, so you will need to add water. If this is the case, follow the manufacturer's directions exactly as printed on the bottle.

Pour your insecticide into a clean sprayer. Pump the handle of the sprayer up and down a few times to build up pressure.

Hold the spray nozzle in one hand. Squeeze the trigger on the nozzle to release the insecticide. Move the wand slowly back and forth to coat the ground. The amount of insecticide being applied will vary depending on the brand.

Wait for the surface of the yard to dry before walking on it.


Things You Will Need

  • Insecticide
  • Lawn and garden sprayer
  • Water