The brown house moth is very common The larvae feed on vegetable and animal materials. They are sometimes found in corn lofts and in food, but cause most damage to moist wool flooring and wool fabrics.
Appearance and lifestyle
The brown house moth has a wingspan of 17 – 26 mm. The front wings are brown-black and have three black stains. The rear wings are somewhat lighter. The larvae (caterpillars) are yellow-white and can get 2 cm long. In unheated areas, there is one generation per year. The moths fly from June to August. The brown house moth is frequently found in buildings. The larvae develop in all kinds of vegetable and animal materials, such as seeds, grain, cork, linen, wool and fur. They can only develop in moist material at a high relative humidity. They are found in particular in quiet and most places, such as under rugs, under floors and in bird nests. Larvae can enter buildings via bird nests.
The damage caused can sometimes be significant. Rugs, mattress and chair stuffing, dried plants, grain products and even linen book bindings can be affected. Mainly somewhat moist wool flooring can be damaged significantly; and from there, adjacent wooden objects (plinths, furniture etc) can also be damaged.
Prevention & Control
First, the area in which the caterpillars (moth larvae) exist must be kept as dry as possible by ventilating during sunny weather or through dry-firing. In case of leakage or permanent moist circumstances, architectural measures must be taken first.
Then, control actions can be initiated, with the help of an agent based on cyfluthrin, deltamethrin of permethrin. These agents should be sprayed on the places where the larvae are found, such as under the edges of the flooring, behind plinths and in the seams and cracks of the bottom of wall furniture. Mainly when the bottom of a furniture piece is shielded by a plinth, this is where the larvae will pupate. At the sprayed locations, a toxic residue is applied, which will retain its deadly effect on the insects for several months. The aforementioned agents are permitted for the extermination of crawling insects. One should spray these agents under low pressure and with course drops. During the treatment and the 2 hours thereafter, the area should be ventilated thoroughly. Afterwards, people and pets can return to the treated area.