Diatomaceous Earth (DE) is a fine powder derived from the fossilized remains of diatoms, which are ancient, hard-shelled microalgae. These microscopic shells are primarily composed of silica and have a porous, abrasive structure. DE functions as a mechanical insecticide, working by physical action against pests with hard exoskeletons. The sharp edges of the DE particles scratch the insect’s waxy outer layer, causing rapid moisture loss, which results in dehydration and death.
Understanding Diatomaceous Earth Grades and Safety
The effectiveness and safety of Diatomaceous Earth depend entirely on the specific grade being used. The two main grades are Food Grade and Filter Grade, which are chemically distinct due to how they are processed. Food Grade DE is minimally processed and consists mostly of amorphous silica, making it safe for use around people and animals. Filter Grade, also known as pool grade, is chemically treated and heated (calcined), transforming its silica content into a high percentage of crystalline silica, making it toxic and only suitable for industrial filtration purposes.
Only Food Grade Diatomaceous Earth should be used for pest control in a home or garden setting. Even though Food Grade DE is considered non-toxic, users must still take precautions to avoid inhaling the fine dust. The abrasive particles can irritate the lungs and respiratory passages, similar to breathing in any type of fine dust. Always wear a dust mask or respirator, along with gloves, during application to prevent lung irritation and skin dryness.
Applying DE for Indoor and Outdoor Pest Management
Diatomaceous Earth is effective against a wide array of crawling pests, including ants, cockroaches, fleas, bed bugs, and silverfish, because they all have exoskeletons susceptible to the powder’s abrasive action. The application technique is crucial for success, requiring a light, barely perceptible dusting rather than thick piles. Applying a heavy layer can actually deter pests from walking across it, allowing them to bypass the treatment area entirely.
For indoor pest management, apply the powder with a duster or shaker directly into cracks, crevices, and other hidden areas where pests travel or hide, such as along baseboards, under sinks, and behind appliances. The goal is to place the powder where it will not be disturbed or become airborne, minimizing the risk of inhalation. If treating carpeted areas for fleas, lightly sprinkle the powder, work it into the fibers with a broom, and then leave it for a few hours before vacuuming thoroughly.
When using Diatomaceous Earth outdoors, the key limitation is moisture. The powder loses its desiccating power when wet, so applications should be done on dry days. Dust the powder directly onto the soil around plants or use a bulb duster to apply a fine film to the leaves, including the undersides, to target aphids, slugs, and beetles. The product must be reapplied after any rain, heavy dew, or overhead watering to maintain its effectiveness.
Integrating DE into Pet and Livestock Care
Food Grade Diatomaceous Earth can be integrated into animal care routines for both external and internal parasite control. For external pests like fleas and ticks on dogs and cats, the powder can be lightly dusted onto the animal’s coat. When dusting pets, take care to rub the powder down to the skin, avoiding the animal’s eyes and nose to prevent respiratory irritation. You can also lightly dust pet bedding, kennels, and the surrounding environment to help eliminate the pest life cycle.
For livestock, such as chickens, goats, and cattle, DE is commonly used as a feed additive to help manage internal parasites, acting as a non-chemical dewormer. The Food Grade powder is mixed into the animal’s feed, where its abrasive nature is believed to help break down the protective coating of internal worms, allowing the animal’s system to pass them. Consult a veterinarian or livestock expert for the appropriate dosage rates specific to the animal species and their size. The addition of DE to feed also helps prevent clumping and improves the flowability of stored feed.
Storage and Reapplication Guidelines
Diatomaceous Earth’s mechanical mode of action means that it does not degrade chemically over time, giving it an indefinite shelf life if stored correctly. The primary factor that affects its long-term efficacy is moisture. To ensure the powder remains effective for pest control, store it in a sealed, airtight container, such as a glass jar or plastic bucket, in a cool, dry location away from humidity.
Reapplication is necessary whenever the powder is compromised by moisture or removed through cleaning. Indoors, DE applied to cracks and crevices can remain effective for long periods unless it is disturbed by cleaning, mopping, or vacuuming. Outdoors, a fresh application is required after any significant rainfall or prolonged exposure to heavy dew that causes the powder to clump and lose its desiccating capability. Once a pest infestation is resolved, the remaining indoor powder can be safely removed by carefully vacuuming the treated areas.