This is another case where a little bit of knowledge is actually worse than none at all. Moles do feed on earthworms as well as a host of other soil grubs which feed upon and destroy prized garden plants. Eliminating the mole's food supply may temporarily decrease mole activity, but the loss of earthworms and their impact on garden soils far outweighs the unsightliness of mole hills scattered across the landscape. Although they are small, earthworms are enormously productive in creating a favorable soil environment for plant growth. According to Eileen Kladivko, an entomologist at Purdue University, earthworm burrows offer more than just an easy path for plant roots.
Worms excrete organic matter rich in phosphorus, potassium, calcium, magnesium, iron and sulfur.
They also convert mineralized forms of nitrogen, phosphorus and potassium into more soluble, readily available forms for plant uptake. As they feed on crop residues, worms distribute nutrients and humus through the soil profile and mix organic and inorganic soil components adds Kladivko. That's why soils with active worm populations tend to exhibit greater moisture holding capacity, better soil structure and a more stable pH. Rain or shine, earthworms are working to improve soil health in your garden and they do it all for free. Encourage rather than eliminate their populations. This site was featured on tv Q13's Click This news segment recently, so I couldn t resist.