How To Control Silverfish
Silverfish, firebrats, and booklice are grouped together because they occur in the same or similar habitats. They prefer a dark, moist environment and require a large supply of starchy foods or moulds. Although they are found in closely associated environments, silverfish and firebrats belong to an entirely different insect order than booklice. Each of these insects are considered to be nuisance pests that can feed on wallpaper pastes, natural textiles, books, and manuscripts. They also feed on mould that grows on various surfaces.
Silverfish, firebrats, and booklice can live indoors or outdoors. They are frequently introduced into a structure with storage boxes, but they can also wander in from outside. They are fast-moving and can travel throughout buildings. Once these insects find a good source of food, however, they stay close to it. In general, they do very little damage, but they may cause people to take radical action based on their fear of insects.
Identification and Biology
Silverfish and firebrats belong to an order called Thysanura. Insects in this order are considered to be some of the most primitive insects alive today. Insects in the order Thysanura have characteristic, three long tail-like appendages attached to the tapered posterior end, each about as long as the body. These insects are wingless, with chewing mouth parts, long antennae, and their body is covered with scales. The mouthparts of silverfish and firebrats are used for biting off small particles or for scraping at surfaces. The most common species inhabiting buildings are in the genus Lepisma (silverfish) and the genus Thermobia (firebrat). The silverfish (Lepisma saccharina) is about 1/2 inch long when fully grown, and covered with silvery scales. It is grayish to greenish in color and its body has a flattened-carrot shape. The firebrat (Thermobia domestica) has a mottled appearance with patches of white and black, and is shaped similarly to silverfish.
Silverfish and firebrats eat material high in protein, sugar, or starch, including cereals, moist wheat flour, starch in book bindings, sizing in paper, and paper on which there is glue or paste. These insects often attack wallpaper, eating irregular holes through the paper to get to the paste. Silverfish may bite very small holes in various fabrics, including cotton, linen, and silk, even though they cannot digest either linen or cotton. Firebrats will feed extensively on rayon, whereas silverfish usually damage it only slightly.
Characteristics of the silverfish, Lepisma saccharina:
- lay eggs in any season and take 19 to 43 days to hatch
- the life cycle from egg to adult is three to four months molting at least three to four times
- prefer moist areas (75 to 97% humidity) and moderate temperatures (70° to 80° F)
- active at night or in dark places and may be found throughout the building
- adults lay one to three eggs per day and live two to 3.5 years; the biotic potential of one female is 1,500 to 3,500 offspring
- adults molt up to 50 times
- leave yellowish stains on fabric
- outdoors, live in nests of insects, birds (especially pigeons), and mammals, and under the bark of trees.
Silverfish are found in bookcases, on closet shelves, behind baseboards, wallpaper, window or door frames, wall voids, attics, and sub-floor areas. They prefer bathrooms and kitchens because of the moisture associated with these areas. Firebrats will be found in similar but warmer areas. Both silverfish and firebrats moult as many as 50 times during their adult lives, therefore the appearance of cast skins may be a useful detection tool.
Treatment 1 (Natural)
Dehumidifying reduces the moisture content of the air that these insects find essential. Some methods for dehumidifying include:
- Mend leaking pipes.
- Ventilate closed rooms and attics.
- Eliminate standing water.
- Use a dehumidifier
Regularly vacuuming cracks and crevices with a narrow vacuum tip also can be a good method to physically remove these insects from their harborages
Removal of food
Excess food material should be eliminated. Food sources that can not be removed should be sealed in containers.
Silverfish can be trapped on small Insect Monitor Traps
Eliminating Harborage Sites
Wherever possible, potential hiding areas should be sealed with caulk, especially around windows, cabinets, and moldings. Increasing the lighting makes harborages less hospitable. Removal of leaf litter from around the home can decrease the chance of an outside invasion.
Drying Stored Articles
Periodic airing and drying of articles stored in damp areas may help reduce the mould on which these insects feed. Disposing of mouldy articles is often the simplest way of removing an infestation in an area.
Non Chemical Control
Diatomaceous earth 350gm can be used to dry out these insects. Diatomaceous earth and borate-based products must be kept dry to be most effective.
Treatment 2 (Chemical)
Residual insecticide can be applied to the area where silverfish or firebrats are commonly seen.
Pro-Active C Silverfish Control Spray can be used in virtually all areas safely. Keep children and animals away from the treated area until the product is totally dry, about 1-4 hours.
Apply Pro-Active C to wall/floor junctions throught the affected area, spray under washing machinse, cookers etc. Pay particular attention to dark secluded areas and around boilers.
Re-apply the treatment after 30 days to ensure total eradication of the Silverfish.