We had a mole problem; my father and sister tried to catch them with traps and couldn't. So my mother bought a trap (sadly one that kills the mole), set it in the run and put an earth worm in front and behind it. It caught the mole within hours and was very effective. It was sad to have to resort to that, but we didn't want to use chemicals, and our Labrador doesn't have the patience of most terriers.