Moles In The Landscape (Part I) Friend or Foe?
Although there are other species, the most common mole in our East Texas sandy soil landscape is the Eastern Mole, a relatively small but robust, short brown-furred mammal that can tunnel in the right soil conditions at speeds of 15 feet per hour and can consume more than 66% of its’ body weight in 18 hours. No wonder it seems like those well known raised feeding tunnels and raised excavation mounds seem to pop up over night. Moles are solitary creatures except for breeding time. It is rare to find more than five per acre.
The burrowing activities of moles cause the most damage on golf course greens and lawns, and in situations where accelerated soil erosion may result. Additionally, they have been known to wreak havoc by burrowing along crop rows and in garden beds. Contrary to the belief of many, moles are not specifically going after the roots of your plants. In most cases, they are searching out their main diet of earthworms and grubs. However, beetles, spiders, centipedes, as well as insect larvae and pupae, and some vegetable matter are occasionally ingested. Note that the burrowing activities of moles tend to aerate the soil, which is beneficial to plants. Sometimes the insect larvae removed by a mole can do far more damage to vegetation than the mole does. For example, larval June beetles (white grubs) feed on the roots of grasses and may, if present in large numbers, completely destroy the sod in an area. Moles occasionally attack the underground nests of yellow jackets and other wasps.
However, the soil displacement that moles cause can break the heart of many a yard loving East Texan gardener, as well as the fact that mole tunnels have been known to be used by voles (field mice) which are voracious root eaters.
So I leave it to your own conscious with these choices:
- Co-exist in a humane way. Get creative with those sandy mounds or replace your grass with a ground cover.
- Repel. This means basically packing them off to your neighbor’s yard.
- Trap live and relocate. Some success has been accomplished digging into active tunnels and placing coffee cans beneath the tunnels so mole falls in, accuracy is obviously a big factor here. Take care not to leave a human scent.
- Or when all fails ….Execute the little monsters! But educate yourself; this task can also be very difficult and potentially time consuming.
Moles In The Landscape (Part II) How to Get Them!
My initial response to moles was to repel them with commercial caster bean oil based spray that attached directly to my garden hose. The oil irritates the furry little creatures and makes them go elsewhere. If next to a wooded area, this method is almost futile unless constant re-application is tended to. Since then, I’ve seen enough mounds in my lawn to justify the use of any possible weapon of mole destruction.
However, to be fair to those of you that don’t have my mole murderous intents, I’ve broken down some options below. With any solution, I highly recommend studying more about your enemy before choosing your own line of attack. Mole’s subterranean life has proven a fascinating subject, and success can be dependent upon how much you know about your enemy. The internet and publications at your local extension office can be valuable assets.
Doesn’t Work, Limited Success, or just a Bad Idea:
- Human hair, chewed bubble gum, broken glass, engine oil, mothballs, gasoline, drain cleaner, chocolate covered laxatives placed down tunnels. (Frankly as well as not working, some of these are quite dangerous or toxic as well as environmentally unsound)
- Sonic devices (or) windmills that emit sound or vibration (proven ineffective for long term control by researchers at WSU)
- Attempting to flood the tunnels in a sandy porous soil.
- Planting dense or the occasional Castor Bean Plant, Marigold, gopher’s purge (Euphorbia), or Fritillaria. While all of these have limited success in a small garden, all are toxic to children, pets, and wildlife (i.e.) there is a reason they repel moles.
- Insecticide to kill Mole’s food source (Earthworms; grubs) bad idea as moles can eat other things not affected by insecticides and you are killing something that’s good for the soil. Many insecticides are harmful to people, pets, and wildlife.
- Fumigation: Smoke bombs are difficult to set properly and rarely succeed in full control.
- Poison baits (unless there is a similarity to earthworms or grubs) are generally ineffective, and toxic to pets and other wildlife if they gain access.
- Caster bean oil-based repellents (expensive, needs to be re-applied after heavy rain, lasts only a month or so) can be an effective method to repel at minimal and safe toxicity levels. They will come back.
- Barrier Construction – (practical for small areas only) constructed of 36-inch wide aluminum sheeting or 1/4-inch mesh galvanized hardware cloth. Bury to a depth of 24 to 30 inches and allow 6 inches to extend above the ground surface.
- Watching a Rolling Lawn- direct killing or shovel flipping of observed “working” moles. Can be time consuming but assisted using thin wire flags stuck in tunnels.
- Live Capture – Dig and place large 3 lb. coffee cans under and even with active runway. Partially collapse tunnel on both sides of the coffee cans. Place a large board to shut out light. Mole will fall into pit trap.
- Trapping/Killing – The most successful method for long-term eradication is trapping. Choices of traps include the harpoon, scissor jaw, and choker. In our sandy soils, the harpoon (Victor Spear or Plunger trap) is the most recommended by experts. Although where active runways are deep or soil is hard, a different trap or certain amount of excavation may be needed.
- Dogs/Cats – Although cats seem better on surface shrews, both dogs and cats can have a natural inclination towards killing moles. However, a dog on a long chain in an observed active area, may fair well.
Scott Martin, former Smith County Master Gardener
Texas A&M AgriLife Extension Service
THE PESKY MOLE
Moles are small mammals that live almost entirely underground in a vast network of interconnecting tunnels 3 to 30 inches (7.5 – 75 cm) deep. The main runways are usually less than 2 inches (5 cm) in diameter, and may be 16 to 18 inches (40 – 45 cm) below the surface. Moles dislodge turf grass and plants as they push up through the soil from just below ground level looking for worms, insects, and other invertebrates. Surface feeding burrows appear as ridges. The mounds formed by moles are pushed up from an open center hole. The soil may be in chunks, and single mounds often appear in a line over the runway connecting them.
Trapping is the most dependable method of controlling moles. Various mole traps are available at hardware stores or nurseries. Traps are generally set straddling or encircling the runway. Before setting traps, determine which runways are in current use. Moles dig a system of deep tunnels as well as a network of surface runs that may only be temporary. To determine which ones are active, stamp down short sections of surface runways and observe daily for signs of activity. Set traps at least 18 inches from a mound and only in runways used daily. Deeper tunnels can be located with a probe. Remember to fill the portion of the tunnel under the trap’s trigger with loose soil.
Art Phillips, Smith County Master Gardener
Texas A&M AgriLife Extension Service