Earthworms feed on fairway clippings returned after mowing and on organic matter in the soil. They love the consistent, moist, fertile conditions that typically are present in fairway turf. In other words, earthworm casting is not an indication of a superintendent's inability to grow healthy turf. In fact, the opposite is true. Based on field observations, Lumbricus terrestris, commonly known as the night crawler, is the earthworm species causing severe casting damage on golf courses in many locations across the country.
Night crawlers can live long lives, with a reported average life span of six to nine years.
They breed, on average, once every two weeks, producing up to 20 offspring with each cycle. Breeding activity is greatest in the cool, moist conditions of spring and late fall, which also results in increased casting activity as they surface to find a mate. Researchers report that one mature night crawler can produce several hundred offspring in one year. The young night crawlers can grow several inches per year and are sexually mature after the first year. Because fairways provide optimal living conditions, unlimited space and a constant food supply, it is easy to see how earthworm populations and casting can get out of control.