The name dust lice is confusing, because these insect are not related to lice and have nothing to do with dust. They belong to a separate order within the insect realm. Al lot of species are very common. The presence of a couple of dust lice in an area or stored products is harmless in itself. They do not pose a health risk. However, their presence is a clear sign that the area in which they are found or the product in which they live, is too humid.
Dust lice are small insects. Their are max. 4 mm long. Their colour is white, grey or brown. Some species are winged; other species have wing stumps or are wingless. They can move quickly, but do this jerkily so. The young stages of dust lice look a lot like the adult versions.
The duration of the development from egg to adult insect depends on temperature and humidity and can differ greatly per species. In optimal circumstances this development can however be completed within a month. When kept in mind that every female can lay up to a 100 eggs, it is not surprising that they can multiply at an amazing pace.
Dust lice live on fungi that develops on material stored in moist conditions or in humid areas. They sometimes exist in large numbers in humid houses, warehouses and farms. In addition, they can exist in herbariums, insect collections, between humid papers, in old books and in old moist stuffing of mattresses and pillows, in rush matting and other vegetable flooring. When dust lice exist in great numbers, they can cause some material damage. In thatched roofing of houses and farms, dust lice can sometimes exist in great numbers. In case of proper ventilation a natural balance will be created between the dust lice and the predator insects and mites that feed on dust lice.
Prevention & Control
The only effective control method consists of cleaning or drying of the material in which the fungi exist and drying the area in which they live and keeping it dry. The latter can be achieved by ventilating in hot weather or through dry firing.
Recently built houses often have a concrete floor that is not yet entirely dry. Sometimes a stagnating ventilation of crawling space and / or hollow wall is the cause. Rising damp in an exterior wall or condensation of water vapour on a wall can be a cause as well. In such cases, architectural advice may be necessary.
A source for fungus growth can be unfinished particle board in kitchen islands or cabinets, mainly the sides of counter tops and the bottom of cabinets. This materials absorbs moisture by cleaning it with water, causing fungus Proper drying, for instance with a hot air heater, blow-dryer etc and then sealing it with appropriate material, will resolve the problem.
Applying insecticide is useless, because dust lice will simply come back after a while. This means that the area would have to be sprayed multiple times, which is not preferable. A permanent solution can only be achieved by reducing the relative humidity in the areas with dust lice. Moist pallets can be dried by heating them for at least half an hour up to 50 C. which will kill any dust lice present.