Chipmunks are common in suburban and rural areas, often causing frustration when their burrowing and foraging habits damage gardens, flower beds, or foundations. Many homeowners seek quick fixes, and a persistent but misguided idea is to use mothballs as a deterrent. This practice is generally ineffective against chipmunks and introduces significant health and environmental hazards. Using mothballs in this manner is a misuse of a registered pesticide and should be avoided in favor of proven, safer management techniques.
Why Mothballs Are Ineffective Against Chipmunks
Mothballs contain volatile chemicals, such as naphthalene or paradichlorobenzene, designed to slowly convert from a solid into a toxic gas. These fumes are intended to accumulate in high concentrations within sealed environments, like airtight containers, to kill fabric pests such as clothes moths. The product’s effectiveness relies entirely on the concentration of the toxic vapor in an enclosed space.
When mothballs are scattered outdoors, the toxic fumes are rapidly dispersed by air currents, wind, and rain, preventing the necessary buildup of vapor concentration. Chipmunks are highly motivated by available food sources and shelter. A weak, temporary smell will not overcome these strong behavioral drivers to make them abandon an established territory.
Toxicity and Legal Restrictions
Mothballs are classified as pesticides and are regulated by the U.S. Environmental Protection Agency (EPA). Product labels specify exactly where and how they can be legally used, typically only inside tightly closed containers for clothes storage. Using mothballs for any purpose not listed on the label, such as scattering them in yards or gardens to repel chipmunks, constitutes pesticide misuse and is illegal.
This misuse poses serious risks to people, pets, and non-target wildlife. When left in the open, mothballs can be mistaken for candy by children or consumed by pets, leading to severe poisoning. Symptoms of poisoning include vomiting, tremors, abdominal pain, and potentially liver or kidney damage. The chemicals also contaminate the environment, leaching into the soil and potentially harming beneficial insects and plants.
Proven Methods for Chipmunk Management
Management of chipmunks focuses on exclusion and habitat modification. Exclusion techniques involve physically blocking access points to structures and vulnerable areas, which is the most reliable long-term solution. Homeowners should seal any openings in foundations, porches, or decks that are larger than a quarter-inch using concrete, caulk, or quarter-inch hardware cloth. For protecting flower beds and bulbs, burying hardware cloth about one foot deep and extending it a foot or more past the planting area will prevent chipmunks from digging up the items.
Modifying the habitat reduces the factors that attract chipmunks to the area. This involves eliminating readily available food sources, which often includes spilled seed from bird feeders, fallen fruit, nuts, or berries. Bird feeders should be placed at least 15 to 30 feet away from the home, and it can be helpful to switch to seed types chipmunks find unappealing, such as thistle. Removing cover and shelter, like wood piles, dense shrubs, and rock stacks near the foundation, discourages chipmunks from establishing burrows close to the house.
For active control, commercially available repellents that are specifically approved by the EPA for use against rodents can be used, though their effectiveness varies and they require repeat applications. Taste repellents containing capsaicin, a pepper derivative, or Bitrex are applied directly to vulnerable plants or bulbs, making them unpalatable. In cases of persistent or severe infestations, the most reliable method is often trapping, using either live-capture traps for relocation (where legal) or common rat snap traps for lethal control, following state and local regulations.