Posted: 22/10/2015 at 08:31
The reason you're getting a lot of casts on the lawn at the moment is because the worms are nearer the surface due to the wet weather and it indicates that your lawn is becoming waterlogged.
Thorough scarifying and aeration of the lawn will help drainage and the worms will be able to move deeper in the soil which is where they prefer to be. Cooler weather will also encourage them to move downwards.
This is only a temporary problem and there is no need to reduce their numbers - doing so would have an impact on the health of your lawn.