Moles Various mole poison baits and traps will reduce moles burrowing through outdoor beds and stop them from eating earthworms. Some feel that caster oil plants grown beside beds keep moles away. Mice and Rats Mice and rats occasionally raid earthworm beds. Control rodents with permanent bait stations around beds. Rodent baits have given control.
Screens can also keep rats, mice and other pests out of earthworm beds.
Keith L. Smith, Associate Vice President for Ag. Adm. and Director, OSU Extension.