Dealing with Those Pesky Moles and Voles

Moles

While most people have never seen a mole, they are well aware of the damage they cause to lawns and flowerbeds. Most individuals think moles feed primarily on the roots of plants and cause them to die. The truth is, moles feeding on plant material is very limited. It's the air pockets they create around roots and flower bulbs that cause them to dry out and die. Others will swear by a number of home remedies to control or repel moles. These include such things as human hair, Juicy Fruit gum, poison peanuts, mothballs, flooding tunnels with a garden hose and water (flooding tunnels creates a moist environment favorable for earthworms), a hose connected to a cars exhaust and finally, pets (some dogs and/or cats can be effective). A mole lives most of its life underground and are highly specialized animals for their subterranean way of life. The Eastern Mole is a small, sturdy animal, 5½ to 8 inches long, with a somewhat cylindrical body and elongated head. The Eastern Mole is grayish-brown on the back to pale or more brown on the belly. Their velvety fur often has a silvery sheen. Occasionally bright orange or cinnamon-yellow marking will occur. Their fleshy snout serves as a highly sensitive organ of touch and smell to seek out numerous food sources. Their tiny eyes are concealed in fur and covered by fused eyelids; sight is limited to distinguishing light from dark. The greatly enlarged front feet are normally held with the soles vertical and pointing outward. They possess well-developed claws that have a specialized bone attached to the wrist, which aids in digging.

Moles construct networks of tunnels in the soil surface. Many of these are built after rains when the mole is in search of new sources of food and are usually not re-used. Digging of surface tunnels normally proceeds at a rate of one foot per minute. They tend to feed and rest on two-hour cycles, 24 hours a day. Animal foods constitute about 85 percent of their diet. This includes earthworms (their main source of water) and grubs, primarily. However, millipedes, centipedes, spiders, sow bugs, snails and slugs are taken in considerable amounts. Moles are insatiable eaters and can consume 70 to 80 percent of their body weight daily. Moles generally move up or down within the soil profile to follow food sources such as earthworms, which move with soil moisture.

Moles also create mounds (called molehills) of soil in the lawn by pushing up soil developing deeper, permanent tunnels and nesting cavities. Mating occurs in the spring with a single annual litter of two to five young being produced in March, April or the first week of May. High infestations consist of two to three moles per acre.

Management or Control

The re are products on the market that are available to homeowners and can be purchased at local nurseries or garden centers.

Most products tend to work as a repellent based on castor bean oil as the active ingredient. Many have been tested on the Eastern mole and appear effective on that species, which is our predominant species. These products need to be sprayed (garden hose-end applicator) or granule applied (through a spreader) at regular intervals to maintain a barrier that repels these small mammals to your neighbor. The repellent type products are marketed as natural and safe, but information about effectiveness is mixed. Mole-Med may have changed its name to Chase due to new ownership and is available in both liquid and granular form. Other repellents include Scoot Mole, Shotgun Mole & Gopher Repellent, Mole Max, Mole-Out, Whole Control, Schultz Garden Safe Mole Repellent and many others. All are based on some percentage of caster bean oil as the active ingredient. Formulations vary with each, sprayable or granular. These products will generally treat 5,000 to 10,000 square feet and last one to three months. Many of the ready-to-use products are costing around $15 to $20 per item.

More recent products include several baits that seem to be very effective if applied properly to active feeding runways. See below on how to locate active feeding runways. Wear rubber gloves whenever handling and placing baits in tunnels.

Two products called Kaput Mole Control (Lesco) and Moletox Baited Gel (Bonide) are water-based gels containing warfarin (0.025 percent) as the active ingredient and flavored like their primary food, earthworms. It is best to locate the active runways as you would for trapping (next page) before placement of the bait. They are both packaged in syringe-type applicators with which the bait is injected into the tunnels. Usually figure around $20 per syringe. The latest registered mole bait is Talpirid (Bell Laboratories), a bromethalin-based product that actually looks, feels and tastes (so they say) like earthworms. Each worm contains a lethal dose of bromethalin. It is the only mole bait that has submitted efficacy studies to EPA.

This product appears to be a higher cost item at around $50 per box 20 worms.

MOTOMCO Mole Killer is a bait similar to Talpirid, but in a more affordable package of eight worms for around $18 to $22. Gemplers, QC Supply and MFA are carrying this product.

We can also find some poisonous granular baits of a different class as compared to the previous baits mentioned. These include Moletox II and Mole-Nots, both of which are cracked corn baits laced with two percent zinc phosphide. One teaspoon of material will treat an active tunnel. While some results indicate excellent control with these products, keep in mind that moles do not prefer grains in their diet.

Another granular bait is Mole Patrol Bait. Mole Patrol is a ready-touse, pelletized bait highly palatable with unique attractants. This product cont a ins chloropha c inone , a historically sound anticoagulant of the rodenticide industry. Some studies indicate 100 percent control of moles. A one-pound container can be purchased for less than $10.

Trapping is still one of the most efficient means of controlling moles and anyone can be successful by following a few simple steps. If you have the network of shallow runways used for feeding, then you can do some effective trapping. First, you need to locate active feeding runways. Second, select a tunnel to set your trap. There are several types of traps to choose from and simply follow the instructions of the manufacturer to set the trap. The Nash trap (wire hoop type) and the Victor Out O' Sight trap (scissors type) do work, but seem to be more diffi cult to set. The Victor Harpoon or Gig type trap has been the most successful trap for us at the MU Turfgrass Research Center.

Identifying Active Feeding Runways

First, with a small stick or broom handle, poke holes in various runways over the entire network. Come back two to three hours later and inspect those holes. Find the tunnels with the holes plugged back up. This will indicate to you which runways are active feeding tunnels at that time. These are the tunnels that you want to set your traps on or place baits in.

Controlling and trapping moles requires a little time and patience. Your success with controlling moles is dependent on locating active runways and the proper placement of a trap. Additional information on moles can be found in MU Guide #9440, Controlling Nuisance Moles.

Voles

Voles are small mammals that occur throughout Missouri. Commonly called meadow mice, they are distinguished from true mice by their short tails (about an inch long), stocky bodies and short legs. Their eyes are small and their ears are partially hidden. They are usually brown or gray, but can vary in color. Three species of voles occur in the state, the pine or woodland vole, the meadow vole and the prairie vole. These three vole species differ in color and size. However, it usually is not necessary to distinguish between the species to control the damage they cause.

Voles eat a variety of plants, such as forage grasses, legumes and crops. Voles also tend to live in colonies. A vole colony may have several den openings connected by a network of underground runways. The runs of the meadow and prairie voles are on the soil surface and lead to underground dens, while the runways of the pine vole are usually underground. Vole colonies consist of a pair of animals but more than likely will include several generations. A colony can have runways covering an area as large as a quarter acre. Although voles have value in the natural world, homeowners and managers of valuable horticultural plantings may need to use measures to control damage from voles.

Controlling Voles

The reduction of large vole populations is accomplished most effectively with toxic baits. A good rodenticide program can be both effective and economical for home gardeners as well as commercial producers when vole damage is severe.

Toxicants have been a mainstay in vole damage control. Zinc phosphide has been the toxicant most frequently used. It is a single-dose toxicant available in a pelleted formulation. Zinc phosphide baits generally are placed by hand in runways and burrow openings. Although pre-baiting (application of a non-toxic bait prior to applying toxic bait) is not usually needed to obtain good control, it may be required in some situations such as when a population has been baited several times and bait shyness has developed. ZP Gopher Bait is the best zinc phosphide bait to kill voles.

Home gardeners and managers of horticultural landscapes should consider using one of the labeled anticoagulant rodent baits to control voles. Anticoagulants require multiple feedings to kill the animal (over five to 15 days). These rodenticides are usually safer around nontarget species, and bait shyness will not develop as the animal never associates a weakened condition with the bait. Currently, warfarin formulated in pellets (sold as Kaput Rat, Mouse and Vole Bait) is recommended for use by homeowners and managers of horticultural landscapes for controlling voles. This product can be ordered on various Websites. Be sure to read and follow all label directions when using any rodenticide.

Bait placement and use of bait stations. Place two tablespoons of pellets under a covered runway or in an entrance hole that is actively used by voles. Establish these covered bait stations at 10-foot intervals throughout the infested area. Placing these baits in protected areas will attract the rodent to the station, prevent ingestion by nontarget animals and minimize exposure to the weather.

Bait stations can be made from two- to three- inch PVC pipe constructed in an L-shape or upside-down T-shape (See below). The horizontal pipe should be at least 12 inches long. Bait stations can also be made from rolled tar paper, mailing tubes or similar durable materials.

After about five days, repeat the baiting. Repeat the baiting process only in those areas still showing vole activity.

Brad S. Fresenburg
Extension/Research Associate
University of Missouri Turfgrass
Research
FresenburgB@missouri.edu