The Miller moth, most commonly the adult form of the army cutworm (Euxoa auxiliaris), is a familiar seasonal presence across the Western United States. These moths appear in large numbers during their annual spring and early summer migrations, often leading to temporary invasions of homes and businesses. When these dusty, fluttering insects appear inside, concern arises about potential damage to household items, particularly clothing and stored fabrics. Many wonder if the Miller moth is responsible for mysterious holes appearing in their garments.
The Definitive Answer: Do Miller Moths Cause Damage?
The answer is no; Miller moths do not consume clothing or household fabrics. They are classified as nuisance pests because of their sheer numbers and tendency to congregate indoors, not as destructive pests. Adult Miller moths lack the mouthparts necessary to chew or digest natural fibers like wool, cotton, or silk. If you find damage to stored items, the Miller moth is not the culprit. Their presence inside homes is a temporary stopover during migration, as they do not feed or reproduce indoors.
What Miller Moths Actually Consume
The adult Miller moth’s diet consists primarily of liquid sustenance gathered from the outdoor environment. They use a long, specialized tube called a proboscis to sip nectar from flowering plants, making them active pollinators. During migration, they feed on flowers to fuel their journey from the plains to higher elevations, where they spend the summer months.
The larval stage, known as the army cutworm, feeds on various outdoor vegetation, including grasses, alfalfa, winter wheat, and other crops. Army cutworms spend the winter feeding and grow in the spring before pupating in the soil. Adult moths enter homes accidentally, attracted by light sources at night or seeking cool, dark shelter during the day. They are simply resting, not nesting, and they do not reproduce or feed inside the structure.
The True Culprits of Fabric Damage
The damage often wrongly attributed to the Miller moth is caused by the larval stage of other, smaller insect species. The most common household pests that feed on clothing and textiles are the Webbing Clothes Moth (Tineola bisselliella) and the Casemaking Clothes Moth (Tinea pellionella). These moth larvae feed on animal-based fibers that contain the protein keratin, such as wool, silk, fur, feathers, and leather.
Another group of destructive household insects is the carpet beetles, including the varied carpet beetle (Anthrenus verbasci). Carpet beetle larvae are keratin feeders and can damage items ranging from upholstered furniture to stored garments. Evidence of these true fabric pests includes small, irregular holes in clothing, silken webbing or tubes left by clothes moth larvae, or shed larval skins. These larvae prefer dark, undisturbed areas like closets and storage containers, which allows infestations to go unnoticed.