Moths are a diverse group of insects in the order Lepidoptera, shared with butterflies. They represent the vast majority of this order, with approximately 160,000 known species globally. Most are nocturnal, active at night. These species vary remarkably in size, appearance, and behavior across environments.
Moths That Damage Property
Some moth species cause considerable property damage, primarily during their larval stage. Clothing moths, such as the webbing clothes moth and casemaking clothes moth, are common culprits in homes. Their larvae consume keratin, a protein in natural fibers like wool, silk, fur, feathers, and leather, creating irregular holes, silk webbing, and fecal pellets on items. These pests infest clothing, carpets, upholstered furniture, and other textiles, often damaging items in undisturbed storage.
Pantry moths, including the Indian meal moth and Mediterranean flour moth, target stored food products. Their larvae contaminate dry goods such as grains, cereals, nuts, dried fruits, and even pet food with silk webbing and droppings. This contamination renders food unappetizing and unsafe, often leading to significant waste. Beyond household concerns, moth larvae like cutworms, the caterpillar stage of certain species, can damage garden plants by feeding on roots or stems near the soil surface.
Moths and Human Health
While property damage is a common concern, moths can present health considerations, though direct risks are generally less frequent. Sensitive individuals may experience allergic reactions to airborne moth scales or fine hairs on some moth larvae. These reactions are typically mild, but can cause respiratory or skin irritation.
Pantry moth contamination of food can lead to indirect health concerns. Larval activity in stored foods can create conditions favorable for secondary fungal growth. Ingesting food contaminated with moth byproducts, including webbing and frass, or these secondary fungal growths, can pose health risks. Certain moth caterpillars, though not common household pests, possess stinging hairs that can cause skin irritation or rashes upon contact.
Managing Moth Presence
Effective management of harmful moths involves preventive and control measures. Proper storage of susceptible items is a primary defense. Cleaning clothing before storage and placing natural fibers in airtight containers or garment bags prevents infestations. Regular cleaning routines, including thorough vacuuming of carpets, rugs, and upholstered furniture, and dusting surfaces, help remove moth eggs, larvae, and potential food sources.
For active infestations, wash affected clothing in hot water or freeze infested items at temperatures below -12°C (10°F) for at least 72 hours to eliminate eggs and larvae. Pheromone traps offer a non-toxic method to monitor moth populations and disrupt their breeding cycle by attracting and trapping male moths. Natural repellents, such as cedar wood and lavender, deter moths with their scents and can be placed in closets and drawers. If a moth infestation is severe, widespread, or persistent despite home efforts, professional pest control services can provide comprehensive treatment, including integrated pest management strategies targeting all life stages of the pest.
Moths That Are Not Harmful
The vast majority of moth species do not threaten human property or health. These numerous species play diverse and important roles within ecosystems. Many moths are significant pollinators, especially for night-blooming flowers. Hawk moths, for instance, pollinate various flowers, some even more efficiently than bees.
Moths and their caterpillars also serve as a crucial food source for many animals, including birds, bats, amphibians, small mammals, spiders, and other insects. This role helps sustain diverse wildlife populations. While a few species can be problematic, most moths are integral and beneficial components of natural environments.