Dry ice, the solid form of carbon dioxide (\(\text{CO}_2\)), offers a distinct method for mole eradication. Unlike water ice, dry ice undergoes sublimation, transitioning directly into a colorless, odorless gas. When introduced into a mole’s tunnel system, the resulting carbon dioxide gas expands significantly. This gas displaces the oxygen necessary for the animal to breathe, effectively filling the subterranean network and leading to asphyxiation.
Essential Preparation and Handling Dry Ice Safely
Before attempting to apply dry ice, it is necessary to confirm the presence of active moles and assemble the necessary safety equipment. Moles create two primary signs of activity: conical molehills composed of loose soil and raised surface ridges that mark shallow feeding tunnels. To identify the most current and active tunnels, you should flatten a section of a raised ridge or stomp down a molehill and check the spot within 24 hours. If the disturbed area is quickly raised again, the tunnel is actively being used and is a prime location for treatment.
Handling dry ice requires strict safety measures because of its extremely low temperature. Direct contact with the solid \(\text{CO}_2\) can cause severe frostbite, similar to a thermal burn, within seconds. You must wear heavy, insulated gloves, as thin rubber or plastic gloves do not offer adequate protection against the cold. The necessary materials include the dry ice itself, an insulated container (not airtight) for transport and temporary storage, the heavy gloves, and a small shovel or trowel for application and sealing.
Carbon dioxide gas is heavier than air and can accumulate in low or poorly ventilated spaces, posing an asphyxiation hazard. Dry ice should never be stored in an airtight container, as the sublimating gas can build up pressure and cause the container to rupture or explode. Always work in an open, outdoor area to ensure proper ventilation and prevent the gas from concentrating at dangerous levels.
Step-by-Step Guide to Applying Dry Ice in Mole Tunnels
Begin the application process by procuring the dry ice, which is typically sold in blocks, pellets, or chips. If you purchase a block, you will need to cut or chip it into manageable lumps roughly the size of a golf ball or a 2-inch cube. Work quickly as the dry ice begins to sublimate immediately upon exposure to warmer air.
Next, locate the active tunnel entrance or the freshest molehill and use a trowel to gently open a small access hole directly into the main runway. Make the opening just large enough to fit the dry ice chunks, minimizing disturbance to the tunnel structure. Place the solid \(\text{CO}_2\) as deeply as possible into the burrow system, maximizing the distance the heavy gas must travel.
For an average mole tunnel, an application of approximately one to two pounds of dry ice is recommended to ensure sufficient \(\text{CO}_2\) concentration throughout the burrow. Push the pieces deep into the tunnel, allowing the heat of the subterranean soil to accelerate the sublimation process. The rapid phase change creates a high volume of carbon dioxide gas that permeates the mole’s habitat.
Immediately after placing the dry ice, the tunnel entrance must be sealed completely to prevent the escape of the gas. Use the excavated soil or a piece of sod to create a firm, airtight plug over the opening. This seal ensures the heavy \(\text{CO}_2\) gas remains trapped in the low-lying tunnels, displacing the oxygen.
Understanding Local Regulations and Follow-Up
Before using dry ice for pest control, it is prudent to check with local and state regulatory agencies regarding its legal use. While carbon dioxide is a naturally occurring, non-toxic substance, the U.S. Environmental Protection Agency (EPA) may classify any product used to kill a pest as a pesticide. In some jurisdictions, using dry ice for this specific purpose without proper registration can be a violation of federal guidelines.
After treating a tunnel, observe the area for the next 24 to 48 hours to confirm the effectiveness of the application. The dry ice typically sublimates entirely within this timeframe, leaving behind no residue or secondary poisoning risk to pets or wildlife. If the sealed tunnel remains undisturbed after two days, the treatment was likely successful.
If new mole activity appears in a different area of the yard, the process should be repeated in the new active tunnels. Once mole activity has stopped, repair the yard damage caused by the tunneling. This involves flattening the remaining mounds and ridges and reseeding the disturbed areas of the lawn.