The earwig is a common household pest often discovered in container gardens. These insects are mostly nocturnal and can cause noticeable damage to tender plant foliage, fruits, and flowers. While they are not harmful to people, finding an infestation in potted plants can be alarming. Effectively managing this pest requires a multi-faceted approach, moving from immediate physical removal to the application of safe topical treatments, and finally addressing the environmental factors that encourage their presence.
Identifying Earwigs and Why They Are Drawn to Potted Plants
Earwigs have a distinct appearance: a slender, reddish-brown body with a prominent pair of pincer-like appendages extending from the abdomen. Damage to plants often appears as ragged holes or chewed edges on leaves, especially on seedlings and soft-leaved varieties, which occurs during their nighttime feeding. Earwigs are primarily attracted to the microclimate created by potted plants, which provides the dark, damp conditions they favor.
Potted plants inherently retain moisture, and drainage saucers frequently hold standing water, creating an ideal, humid habitat for earwigs to hide during the day. The soil surface and organic material, such as peat moss or mulch, offer both protection and a source of decaying matter, which is a key part of their diet. Dark crevices found beneath the rim of the pot or within the container structure also serve as sheltered spaces for these pests.
Immediate Trapping and Physical Removal Techniques
Physical removal methods offer an immediate solution to reduce the earwig population around your potted plants. These techniques capitalize on the earwig’s natural behavior of seeking dark, narrow, and moist shelters during daylight hours. A simple approach is to create a rolled newspaper trap: lightly dampen a sheet of newspaper, roll it into a tube, and secure it. Placing these rolled tubes horizontally on the soil surface of the infested pot in the evening encourages earwigs to crawl inside for shelter.
These traps, which can also be made from short sections of hollow bamboo or garden hose, should be collected early the following morning before the earwigs become active. The captured insects can then be disposed of by shaking them out into a bucket of soapy water. Another effective method is the oil pit trap, which uses a small, low-sided container, such as a tuna can, filled with vegetable oil and a few drops of soy sauce or fish oil. The aroma attracts the earwigs, which fall into the oil and cannot escape. These traps should be checked and emptied daily.
Applying Safe Topical Treatments
Once the population is reduced through trapping, topical treatments can be applied to manage the remaining pests. Diatomaceous Earth (DE) is a natural powder made from the fossilized remains of diatoms, which acts as a mechanical insecticide. The microscopic, sharp edges of the DE particles abrade the earwig’s waxy exoskeleton, causing fatal dehydration. Sprinkle a thin, even layer of food-grade DE directly onto the soil surface around the plant base, ensuring the powder remains dry to maintain its effectiveness.
Insecticidal soap sprays work by disrupting the cell membranes of soft-bodied insects. A homemade version uses one teaspoon of mild liquid soap—not detergent—mixed with a quart of water. This solution should be sprayed directly onto the earwigs when they are active, typically at night, ensuring full coverage. For severe infestations, a targeted application of a botanical insecticide, such as pyrethrins, may be considered. Caution must be exercised with pyrethrins due to their broad-spectrum action, which can affect beneficial insects.
Long-Term Environmental Prevention
Preventing future infestations requires making the potted plant environment less appealing to earwigs. Since they require high moisture to survive, eliminating standing water is paramount. Avoid leaving water in the drainage saucers or trays for extended periods, as this is a prime attractant. Consider elevating the pot slightly using pot feet or blocks to improve air circulation and prevent the base from sitting in residual moisture.
Improving the drainage of the potting medium helps reduce the overall humidity within the container. If the soil is heavy, consider repotting with a mix that incorporates more perlite or coarse material to promote better aeration. Removing surface debris, such as fallen leaves and mulch, also eliminates the dark, moist hiding spots that earwigs seek during the day. Ensure that the potted plants are not placed directly against moist foundational walls or wooden structures, which can provide an easy pathway for the pests to access the container.