The eastern mole (Scalopus aquaticus) can be found from Ontario to Florida. Of the seven species of moles present in the United States, it is the most widespread, and the one that is most likely to disrupt lawns and landscapes with its tunneling.
BIOLOGY: Mature moles are six to seven inches long and weigh three to four ounces. They have velvetlike gray or brown fur, small eyes, no visible ears, and a short, nearly hairless tail. A hairless pointed snout extends about a half inch in front of the mouth, which is full of sharp, pointed teeth. The paddlelike forelimbs, with webbed toes on outward-turned palms, are designed for swimming through soil.
Moles are solitary. Six weeks after spring mating, females produce a litter of two to five hairless young in an underground nest After a month, they leave the nest to fend for themselves. They become sexually mature in one year and live three to five years.
Moles are not rodents. They are voracious insectivores who, in one day, can consume their weight in insect grubs, adult insects, and earthworms. Moles construct two kinds of tunnels. Permanent ones, 10 to 18 inches below the surface, link underground nests and temporary feeding tunnels, which are located at a more shallow depth. These temporary tunnels can be dug a foot a minute.
SYMPTOMS: Surface tunnels are marked by raised ridges of turf or soil. Volcano-shaped mounds or mole hills might also be present. These contain the soil excavated from the deeper tunnels. Although this tunneling aerates the soil and improves water penetration, it can disrupt plants, and the mole hills can be colonized by weeds.
CONTROL: Using an insecticide to eliminate grubs will not make moles disappear. Trapping in the spring or fall is the best way to eliminate problem animals. Traps can be harpoon, scissor-jaw, or choker-loop types. These should be set in active surface burrows. To be sure a tunnel is active, flatten it and see if it is restored. Move traps if they have not been successful after two or three days.
Moles can be prevented from tunneling into individual garden beds by surrounding them with a barrier of quarter-inch hardware cloth buried to a depth of two feet and extending six inches above ground. Castor oil products, such as Mole-Med, have been shown to reduce mole activity if thoroughly watered in. Irrigate with half an inch of water before application, and one inch afterward. Homeowners can prepare their own concentrate by mixing six ounces of pure castor oil with two tablespoons of liquid detergent in one gallon of water. Use one ounce of this mixture per gallon of water per 300 square feet of turf.
A host of other home remedies, including pinwheels, chewing gum, mothballs, bleach, used cat litter, and pieces of thorny branches have failed to provide any consistent relief.