Overview
Moles are extremely beneficial because they consume the larvae and adults of numerous pest insects, such as Japanese beetles, that affect garden, landscape, and flowering plants. Additionally, their tunneling activity loosens the soil, improves aeration, and mixes deeper soils with surface organic material, all of which enhance soil quality. Although moles frequently are blamed for feeding damage on the roots of vegetation or seeds planted in gardens, they rarely cause such damage. However, moles can be a nuisance where their tunneling disturbs lawns and recreational facilities. Garden plants may be uprooted or heaved out of the soil inadvertently as these animals burrow. Commercial bulb growers and producers of row crop producers can sustain economic loss from moles where plants are dislodged and subsequently become desiccated and die, or when harvesting equipment comes in contact with the raised mounds or ridges created by moles and is damaged.
Management Options
Techniques used to manage mole conflicts are broken into 3 major
categories: husbandry methods, non-lethal methods, and lethal methods. These
categories are consistent with the hierarchical design that characterizes most
vertebrate integrated pest management (VIPM) programs. Under an VIPM program, you first must identify the conflict and evaluate its seriousness, then you review and evaluate the options that are available to relieve or permanently
solve that conflict. Then, based on the outcome of that assessment, you select
and apply the management strategies appropriate to the need, starting first
with the simple, inexpensive, and less invasive techniques, but moving on to
the more complex, expensive, or time demanding options where need dictates. A
general rule of thumb of an VIPM approach: lethal options generally are viewed
as methods of last resort, ones used only when all other methods prove
ineffective. Therefore, in this section, we present a review of options that
follow the VIPM hierarchical approach.
For commercial agricultural producers, elimination of moles over large areas is difficult, if not impossible. For the homeowner, problems with moles usually can be managed with minimal effort and persistence. Because of moles’ solitary habits and low reproductive productivity, most residential yards can be maintained “mole-free” for a number of years.
Husbandry Approaches
In the past, insecticides frequently were applied to lawns in an attempt to reduce populations of various beetle grubs, which are a major food of moles. The assumption used to justify this approach was that with a reduced food supply, moles would leave the area. However, in practice, applications of insecticide are rarely effective in removing all potential food sources. Moles are able to feed on a variety of invertebrates, not just grubs, and so they simply switch to another readily available food (usually earthworms or night crawlers) rather than leave the treated area. Furthermore, some insecticides that have been applied in the past were toxic to wildlife, particularly granular formulations that were especially attractive to songbirds. This insecticide-based approach is no longer recommended-insecticides should be used to resolve insect problems, not mole problems.
White milky spore, a naturally-occurring fungus now available in commercial form, has been promoted as a means to help reduce the number of grubs and somewhat limit the mole’s food supply. However, the fungus does not seem to survive well in cold climates, so it may not persist through the winter months, particularly in the western parts of Virginia. Additionally, even where milky spore is present, it is effective only on certain insects. Thus, with other natural food items still available, this option alone may not provide desired control.
Non-lethal Approaches
The sonic or vibration producing devices advertised commercially as mole deterrents generally have no proven effect on moles. Similarly, many “home remedies,” such as gassing with auto exhaust, placing broken glass, pins or other sharp objects in the tunnels, and use of harsh household chemicals, usually are totally ineffective, can be hazardous to residents and nontarget animals, and may be illegal.
Repellents: Until recently, repellents have not been proven effective in reducing or eliminating mole activity. A new repellent formulation, which contains castor or ricinus oils, has received registration for use in Virginia. This repellent is designed to be applied as a soil drench. However, because this product is relatively new, comprehensive testing has yet to be performed to assess its overall effectiveness under field conditions in Virginia.
Barriers:
Sometimes limited areas, such as seedbeds or small gardens, sustain persistent mole damage. For such areas, installation of a perimeter barrier constructed of sheet metal or hardware cloth may be appropriate. To install such a barrier, first dig a trench about 12-15 inches deep and 10 inches wide around the entire outer edge of the bed to be protected. Place about 8-10 inches of the barrier material into the bottom of the trench, then fold or bend the material upright to create an “L” with the foot of the “L” extending out away from the bed. The barrier material should then extend upward and about 5 inches above the ground surface for complete protection. Backfill the trench with soil to hold the barrier in place and to give it support. All connections in the barrier, especially the corners, must be secure if this barrier is to be effective.
Lethal Approaches
Trapping:
Trapping should be viewed only as a temporary fix to mole problems because it treats a symptom rather than the root cause of the problem. If you are successful in removing an offending individual from the environment, that effort alone does nothing to alleviate or alter the conditions that attracted that animal initially. If the habitat, food supply or other attractant is not modified, other individuals are likely to replace the individual(s) you removed.
To live trap moles, one uses a container into which the moles will fall and be unable to escape, commonly referred to as a “pit trap.” However, you must first determine which runways are active before installing these devices. The best time to trap moles is in the spring, as soon as the first ridges are noted, or after the fall rains. The identification of main or frequently-used runways is of prime importance. To determine which runways are active, stamp down a short section of each runway with your foot and place a marker at each of these locations so that you will be able to relocate them. Observe daily for several days, stomping down any freshly raised sections. If a tunnel is raised each day, you have found an active runway. This is where a trap should be placed.
Dig a hole through the center of the most active runway sufficiently large enough to place a #10 tin can (approximately 7 inches in diameter and 10-12 inches deep) upright in the hole. Be sure the top of the can is level with the bottom of the runway. Fill and pack dirt tightly around the sides of the can, and then plug both sides of the runway with soil right up to the lip of the can. You may also want to stamp the runway about 1 foot on both sides of the can. Lay a board, plywood scrap or other suitable material on the ground over the pit to block out light and prevent pets or children from falling into the hole, but allow you to maintain easy access for monitoring. In reopening the runway, the mole will fall into the can and usually is unable to escape. If the tunnels are not reopened or you fail to catch a mole within 1-2 days, move the device to another active runway.
Captured animals can be released in other areas of your property where their activity will not be objectionable or you may perform humane euthanasia (recommended methods include lethal injection by veterinarian, cervical dislocation, gassing with CO2). Before handling any animals, wear heavy gloves and long-sleeved garments to protect yourself from scratches and bites. Regardless of whether you believe any harm will result from your action, it is illegal in Virginia to transport and liberate any wild animal captured on your property to property of another (including federal, state, or municipal lands) unless you have first obtained a permit to do so from the Virginia Department of Game and Inland Fisheries.
Although a variety of “kill traps” (e.g., harpoon, scissor, or body gripping types) can be purchased at many farm supply and hardware outlets, their use as a means of eliminating or reducing mole damage can be dangerous. These traps often are difficult to set and properly place without risking personal injury. Additionally, there is potential for injury to small children and pets that play near or with unattended mole traps. For these reasons, lethal trapping should be left only to those trained in the operation of such devices and the handling of wild animals.
Fumigants and Toxicants
Although several fumigant products are registered for use in Virginia, all formulations are classified as “Restricted Use Only” products, as are many formulations of registered toxicants developed to kill moles. In such situations, unless you have current Pesticide Applicator Certification in Category 10 (Vertebrates), these materials are unavailable to you. Therefore, use of fumigants and toxicants should be left to licensed or certified pesticide applicators. In instances where use of a particular toxicant formulation is not restricted (e.g., certain formulations of chlorophacinone and zinc phosphide), it is imperative that these materials are placed into the burrow system below ground as a means to reduce nontarget exposure. One thought to keep in mind-given that moles are insectivores, they usually don’t recognize treated grains or pellets as food. Therefore, toxicant treatments often are ineffective in reducing mole activity and damage.
Legal Considerations
The mole is classified as a non-game protected species. Virginia code allows for the taking of a species found committing or about to commit depredation upon ornamental or shade trees, agricultural crops, wildlife, livestock or other property or when concentrated in numbers and manners as to constitute a health hazard or other nuisance 29.1-100. The nuisance classification does not pertain to threatened or endangered species, animals classified as game or fur-bearing animals, and those species protected by state or federal law. All species of mole are capable of being classified as a nuisance by Virginia landowners. As with all wildlife non-lethal control measures should be exhausted before lethal measures are used.
In Virginia it is illegal to:
- Set a trap where it would be likely to injure persons, dogs, stock or fowl 29.1-521,
- Not visit all traps once each day and remove all animals caught 29.1-521,
- Transport, release, or relocate a mole anywhere other than the property it was caught on 4VAC15-30-50, and
- Poison any animal (including moles) other than rats and mice on your property 4VAC15-40-50.
In Virginia it is legal to:
- Classify a mole as a nuisance if it is committing or about to commit depredation upon ornamental or shade trees, agricultural crops, wildlife, livestock or other property or when concentrated in numbers and manners as to constitute a health hazard or other nuisance therefore allowing for the taking of the animal. ยง29.1-100