Most rodenticides are not effective against moles. These poisons typically mimic grains, however, moles do not eat grains. Moles feed on earthworms, grubs, and other insects. Mole bait comes in three forms: gels, worms, and pellets. Correctly placing mole bait is the most difficult part of baiting moles. The first step is locating an active surface tunnel.
Moles dig surface tunnels as they ‘swim’ immediately under the surface of the soil in search for food. This leaves a visible upheaval of soil in lawns and gardens. In order to check if the surface tunnel is still active, poke a hole through the soil into the tunnel. Check the hole over the next couple of days. If it has been sealed, then you know it is an active tunnel. Apply the mole bait by poking a new hole in the tunnel. This hole should be only slightly wider than the bait. Insert the bait and seal the hole with dirt and rocks.
Mole bait gels are scented to taste like earthworms. Their active ingredient is warfarin and they are injected into surface tunnels. Fake earthworms laced with lethal bromethalin are very effective forms of mole bait. These can be bought in packs and are dropped through small holes into surface tunnels. A single worm contains enough poison to kill a mole. There are a few baits in the form of pellets that have been effective, but products that smell or look like worms may give a higher rate of successful mole control.