INTRODUCTION: All members of the order Thysanura have a teardrop/carrot/fish-shaped body and get their common name of bristletail because of their 3 long, bristle like or tail like appendages on the posterior/rear end of their body. Silverfish is a common name for species of this group whose bodies are covered with silvery scales. Silverfish are found throughout the United States and the world.
RECOGNITION: Adult body length, not including tails is about 1/2 to 3/4 inches. Wingless with a flattened body. Teardrop shape, and fish like body tapering from head to rear. Generally covered in scales and silvery in color. Antennae are long and thread like.
DAMAGE & SIGNS of INFESTATION: Feeding marks are irregular whether they are holes, notches along an edge, or surface etchings. Yellow stains, scales, or feces may be seen on infested materials.
BIOLOGY: The Silverfish female lays about 1-3 eggs per day, placing them in cracks, under objects, or out in the open. Eggs hatch in temperatures of 72-97 degrees Fahrenheit and 50% to 75% humidity.
HABITS: All these Silverfish species hide during the day and prefer to hide in cracks and crevices. They can be found almost anywhere in a house. Silverfish prefer areas of room temperature (70-85°F/21—29°C) and high relative humidity (70-100°/o). They prefer proteins to carbohydrates and are cannibalistic. Silverfish are often introduced into buildings via cardboard cartons of books and papers from an infested location. They are pests of paper, particularly of glazed paper and paper with sizing, wallpaper and wallpaper paste, etc. Silverfish eat proteins such as dried beef and dead or injured of their kind. The four-lined silverfish is not so limited by temperature and moisture. It may be found attic especially if the roof has throughout a building, in the basement, in wall voids, the wooden shingles, and in the garage. Outdoors, it occurs in the mulch of foundation flower and shrubbery beds, and under the bark of Eucalyptus trees in California.
CONTROL: The key to control is identification which directs one to the preferred areas of habitation and food materials as outlined above. Identification is followed by a thorough inspection of preferred habitat areas and where appropriate food materials are present. Once the infestation(s) is found, selection of an appropriate pesticide and formulation is followed by a thorough application. Many infestations are very localized and environmental modification can greatly enhance control—eg. controlling or eliminating moisture by repairing leaking pipes, sealing up easily accessible cracks and crevices, removal of potential food sources, etc. Dusts, especially in-organics, are particularly effective in wall voids, attics, crawl spaces, bathroom and kitchen fixture voids, subflooring voids, etc. – Treatment for control of the fourlined silverfish will probably require treatment of foundation mulch beds and possibly the underside of shingles. Bookshelf treatment involves a thorough crack and crevice treatment of the bookcase itself, not treatment the books. ULV treatment of heavily infested rooms is helpful in reducing numbers as is the use of a vacuum.