Moles in the Lawn, Control

Encyclopedia Article

Image of turf grass that has sustained mole damage
Turf grass that has sustained mole damage

The eastern mole, Scalopus aquaticus, is the most common mole in Iowa lawns and the cause of considerable "mole rage" throughout the state.  Moles dig tunnels through the soil for burrows and for feeding.  They also deposit soil excavated from deep tunnels on the surface in a volcano shaped mound or "mole hill." 

The surface feeding tunnels push up the sod as raised ridges that appear to wander aimlessly.  The raised sod may dry out and the grass die, causing disfigurement of lawns, golf courses, cemeteries.  The raised ridges may also be “scalped” by lawn mowers causing further damage to the turfgrass and to the mower.  Tunneling in landscape beds may dislodge bulbs or roots and expose them to air.

For details about mole biology, life cycle and control see ISU Extension & Outreach pamphlet # PM-1302B, “Managing Iowa Wildlife – Moles.” 

Faulty assumptions, mis-statements, erroneous conclusions and blatant lies about moles are common.  Below are discussion points that will help answer common questions about moles.

  • Moles are mostly solitary. (1 acre land = approx. 3 moles) (It only looks like there are hundreds!)
  • The "Main Mole Meal" is earthworms supplemented with some insect larvae, centipedes, millipedes, and spiders
  • Moles eat more than their own weight in earthworms daily (HIGH metabolism!)
  • Having moles does not necessarily mean you have grubs
  • Applying insecticides for grubs will not solve the mole problem*
  • Eliminating earthworms is neither practical nor prudent. White grub insecticides do not control earthworms (fortunately!)
  • Moles DO NOT eat bulbs, roots, pets, or small children
  • Moles are active year-round
  • Activity near the surface occurs in early morning and late afternoon in the spring and fall and on cloudy, damp days of summer.
  • The rest of the year is spent in deep tunnels 6 - 24 inches under the surface.
  • Surface runways (feeding tunnels) may be used only once
  • Main runways may be used for years
  • Moles are woodland/woodland edge critters
  • Well-drained, loamy soils are their favorite haunts
  • Moles are built for digging: They can dig surface runs at 1 to 3 ft. per minute!
  • Moles hear well, though they have no external ears
  • Moles see poorly (light/dark) as the eyes are covered with fused eyelids

Benefits of moles:

  • soil mixing
  • soil aeration
  • water penetration to deeper plant roots
  • some biological control of potentially destructive insects

Mole control options

  • Correctly identify the offending critter
  • Decide if damage is worth the effort of control
  • Locate active, main runs
  • Purchase and set mole traps, being careful to follow label directions.  Set traps on permanent runways, not the temporary, meandering feeding tunnels.
  • Inspect lawn for grubs. Don't assume they are present. Treat with insecticide ONLY if white grubs are present or have been a consistent problem in the past.  See our online article, “White Grub Control in Turfgrass” for more information.

* The worst offense committed in the name of mole control is the great landscape lie that insecticides will cure the problem. This mistake has been going on for a very, very long time and it seems to be constantly perpetuated by several things. One, many people want to believe there is a simple cure for complex problems. Two, there is a hint of logic to the gross oversimplification. Three, chemical control for moles is part of our folk-lore (as in, that's how we did it in the past). And finally, there is a profit motive to sell insecticides and insecticide application services, even unnecessary insecticides that waste homeowner time and money and needlessly contribute to pesticide over-use.

NON-Options (These "controls" do not work!)

  • Sonic, ultra-sonic and electromagnetic devices.
  • Repellents (early, encouraging results using castor oil repellent have not been consistent through further testing)
  • Chewing gum
  • Grain or peanut mole poisons
  • Gassing is only occasionally effective as moles effectively and quickly seal tunnels from offensive light and odors.

 

This article adopted from a Horticulture and Home Pest Newsletter article authored by Jim Pease, retired Extension Animal Ecologist, April 3, 1998.