Moths, a diverse group of insects, are often perceived as harmless creatures fluttering around lights at night. While most of the approximately 160,000 known moth species do not threaten humans or property, some types can cause problems. Their potential impact varies depending on whether one considers direct physical interactions or indirect damage to household items.
Direct Physical Interactions
Most adult moths are generally harmless to humans and do not bite or sting. They lack the necessary mouthparts for biting, with many adult moths having a straw-like proboscis for sipping nectar.
The primary concern comes from moth larvae, known as caterpillars. Some caterpillar species possess urticating hairs, which are tiny, spiny bristles for defense. Contact with these hairs can cause skin irritation, including rashes, itching, redness, or hives, a condition known as lepidopterism. These hairs can also become airborne, leading to eye irritation, conjunctivitis, or respiratory issues like sneezing, breathing difficulties, or asthma-like symptoms in sensitive individuals if inhaled.
Household Pests and Property Damage
While adult moths do not typically cause damage, their larval stage is responsible for significant harm to property. Two common types of household moths are clothes moths and pantry moths, each causing distinct forms of damage. The damage caused by these pests is primarily economic and hygienic, rather than a direct health threat from the insects themselves.
Clothes moth larvae damage natural fibers. They feed on materials containing keratin, a protein found in wool, silk, fur, feathers, and soiled cotton. This feeding results in irregular holes in clothing, carpets, upholstery, and other textiles.
Pantry moth larvae infest stored food products. They feed on grains, cereals, dried fruits, nuts, and pet food. They contaminate food with webbing, fecal pellets, and shed skins, making products unsuitable for consumption. Larvae can chew through plastic bags and thin cardboard to access food.
Preventing and Managing Moths
Preventing moth infestations involves consistent household practices to deter them from establishing. Storing dry goods like grains and cereals in thick-walled containers with airtight lids prevents pantry moth access. Regularly cleaning spills and vacuuming crumbs in pantry areas also removes potential food sources for larvae.
For clothing, proper storage is important. Washing or dry-cleaning items before storing them helps eliminate existing eggs or larvae. Using airtight plastic storage tubs or vacuum-sealed bags can protect clothing. Natural repellents like cedar wood chips and lavender sachets deter adult moths, but do not kill larvae.
If an infestation is present, immediate action is necessary. Freezing infested items at temperatures below -18°C (0°F) for at least 72 hours effectively kills moth eggs and larvae. For widespread or persistent infestations, professional pest control services can identify the species and implement targeted treatment plans, including habitat reduction and, if necessary, the application of insecticides.