Earthworm castings on golf course fairways and tees is a challenging issue for many golf course superintendents. Casting occur when worms ingest soil and leaf tissue to extract the nutrients. Then in the evening the worms emerge from their holes to deposit the fecal matter or castings as small mounds of soil. There currently are no chemical controls for worms and we wouldn't want to kill them any way because they are beneficial to the soil (natural aerification). The problem is the castings disrupt the turf surface and aesthetic value. There are some cultural practices that help limit the worm castings. One is sand topdressing, the worms do not like the sharp angular edges of the sand on their skin. The worms simply move to a different area. The worms also do not like acidic soil a simple application of a acidifying fertilizer has been known to help.
Topdressing a tee