Earwigs are a common sight in gardens and can be both helpful and destructive. While they consume pests like aphids and insect larvae, large populations quickly become problematic, chewing ragged holes in soft fruits, flowers, and tender seedlings. Their nocturnal feeding habits mean the damage often appears suddenly, prompting gardeners to seek immediate methods for population control. This article details actionable strategies for killing and deterring these insects to protect garden plants.
Physical Trapping and Removal Methods
Physical trapping exploits the earwig’s preference for dark, moist hiding spots during daylight hours, allowing for easy, concentrated removal. A simple and effective method uses a low-sided can (like a tuna container) filled with an attractive liquid trap. Filling the can with about a half-inch of vegetable oil mixed with bacon grease or soy sauce acts as a powerful lure. The earwigs fall in and drown in the oil. For maximum effectiveness, bury the container so the rim is flush with the soil surface, preventing non-target insects from falling in.
An alternative technique uses materials like rolled-up newspaper or corrugated cardboard. These items are moistened and placed near damaged plants in the evening, providing shelter for earwigs seeking refuge before dawn. The next morning, the rolls can be collected and the trapped insects dumped into a container of soapy water. Daily inspection and disposal of these physical traps is necessary to reduce the local earwig population.
Applying Targeted Dusts and Sprays
For direct population reduction, specific substances can be applied. Diatomaceous Earth (DE) is a mechanical killer composed of the fossilized remains of tiny aquatic organisms. The powder adheres to the insect’s exoskeleton, where its microscopic sharp edges create abrasions that damage the protective, waxy outer layer. This damage leads to rapid dehydration and death, often within 48 hours of contact.
Only food-grade DE should be used in the garden, and it must be applied as a fine, dry dust around the base of vulnerable plants or in cracks and crevices where earwigs hide. The efficacy of Diatomaceous Earth is lost if it becomes wet, requiring reapplication after rain or overhead watering. Contact sprays offer another immediate solution, often using a mixture of water and a few drops of mild dish soap or insecticidal soap.
Soap solutions are effective because the fatty acids disrupt cell membranes and dissolve the earwig’s waxy coating, causing suffocation. The spray must directly hit the pest to be successful, which often requires application in the evening when earwigs are most active. For a stronger organic option, short-residual products containing pyrethrins can be used, but these should be applied cautiously to minimize harm to beneficial insects.
Modifying the Garden Environment
While trapping and spraying offer immediate control, long-term management relies on making the garden less inviting to the earwigs. Earwigs thrive in dark, cool, and damp environments, so reducing sources of moisture and shelter is a foundational strategy. Removing debris such as old boards, rocks, and leaf litter eliminates daytime hiding spots where large groups can congregate.
Excessive mulch, especially wood chips or straw, can also serve as a host environment, making it advisable to keep mulch layers thin or pull them back from the base of susceptible plants. Addressing poor drainage or leaky outdoor faucets helps dry out perpetually damp areas near the garden perimeter. Pruning lower leaves on dense plants like broccoli or cabbage that touch the soil can increase airflow and reduce the humid, dark conditions earwigs prefer.
Watering timing also makes a difference, as watering in the morning allows the soil surface to dry before the earwig’s nocturnal feeding period begins. By eliminating these dark, moist havens, the garden becomes a less hospitable place, naturally preventing future population surges. This cultural control method reduces the need for constant active killing.