AY Honors/Insect/Psocoptera

Bold text Common Name Scientific Name Booklice Barklice Psocids

Liposcelis corrodens

Trogium spp. Lachesilla spp. Psyllipsocus spp. Lepinotus spp.

Booklice, known as paper lice, may crawl in large numbers over stored papers, books, walls, furniture, and other materials in damp, warm, undisturbed areas in buildings especially during the spring and summer months. Sometimes they are found in newly-constructed dwellings containing uncured green lumber or plastered walls. They feed on microscopic mold and mildew associated with high-humidity conditions. Outdoor species are called barklice since they are found under tree bark or leaves. They do not bite humans or animals, spread disease, or damage household furnishings. However, skin irritation may occur on some sensitive individuals.

Identification Booklice (psocids) are minute, soft-bodied, transparent to grayish-white insects about 1/32 to 3/16 inch (1 to 4 mm) long, usually wingless, and may go unnoticed. It is helpful to use a hand lens and flashlight for detection. They resemble lice in size, but are not in the same order as true lice. The head and abdomen appear large, while the thorax (midsection) is narrow. The antennae are long, threadlike, and segmented. Some have chewing mouthparts and large eyes that protrude from the sides of the head. The young appear almost colorless, becoming more opaque with age. They run along exposed surfaces in a jerky, halting manner, and sometimes appear to hop. Outdoor psocids may be winged or wingless. If winged, they are weak fliers and hold the wings in a roof-like position over the body when at rest.

Life Cycle and Habits Booklice are all females and development occurs from unfertilized eggs (parthenogenesis). Females deposit an average of 60 eggs that are white, oval, and covered with a crusty coating. Eggs are laid singly or in clusters near a food source where young white nymphs hatch and feed on molds and mildews. There are four to six nymphal stages with the immatures resembling the adults in form and structure. The life cycle, from egg to adult, takes four weeks to two months or more depending on environmental conditions. There may be seven to eight generations per year with adults dying in cold weather and eggs hatching the following spring. Booklice avoid light and prefer temperatures of 75 to 85F. with relative humidities of 75 to 90 percent. Long periods of humid weather, accompanied by warmth, favor outbreaks.

These insects feed on microscopic molds, fungi, dead insect fragments, pollen, and other starchy foods found in humid environments such as houses, warehouses, libraries, and structures where green lumber is stored or used. Sweating and high humidities may form in wall voids when new lumber becomes enclosed, encouraging booklouse outbreaks. Damp basements, crawl spaces, leaky and sweating plumbing, potted house plants, cereal, flour, bird nests, furniture stuffings of natural plant fiber, paste on book bindings, grains, wallpaper, etc. may harbor booklice.

Control Measures Lowering the relative humidity hinders development or causes death due to desiccation (drying out). Effort should be made to reduce the relative humidity in rooms and buildings to less than 50 percent, drying out of infested materials, and eliminating the food source such as molds and mildews.

Prevention Use a vacuum cleaner with proper attachments to remove debris from cracks and corners of storage areas. Clean up spilled food stuffs such as cereals, and flour. Foods stored for six months or more sometimes become infested especially in damp, dark, warm, undisturbed habitats.

Infested cereals or stored foods can be discarded or supercooled in a deep freeze at 0F for seven days. Books, papers, or upholstered furniture can be dried in sunlight. Ventilate and dry areas with a dehumidifier or fan, or simply open the doors of a damp room. Infestations will usually disappear during late autumn when rooms are artificially heated and kept dry. Even with a new structure containing green lumber and freshly plastered walls, enough drying occurs after one season of summer heating so that infestations rarely occur in the following years.

Store cardboard boxes, books, and papers off the floor and repair plumbing leaks and drains to eliminate standing water. Vent the clothes dryer to the outside and remove leaf litter, vines, and other debris from around building foundations including ground-level window wells. Install a vapor barrier in the crawl space or add additional ventilation in the crawl space or basement. Regrade wet areas around the building and install a drainage tile system to handle rain runoff in problem areas. Seal cracks in interior and exterior foundation walls and repair leaking rain gutters, down spouts, roof vents, and roofs. Allow damp firewood to dry out before bringing indoors.

Insecticides Normally chemical control is not needed if strict sanitation is practiced. Booklice cause no negligible damage to commodities. They are a nuisance by their presence, crawling over areas in large populations. Some apply mothball flakes, naphthalene or paradichlorobenzene in infested closets or file cabinets. Household products that control mold and mildew will reduce the food source of booklice. Treat wall and ceiling voids, attics not used for storage, and cracks and crevices around baseboards, door and window framing and other infested habitats. Household pressurized aerosol cans containing pyrethrins applied on booklice and their habitats are useful indoors, while treatments of propoxur (Baygon), diazinon or chlorpyrifos (Dursban) may be applied to structure foundations, rotting logs, grass piles, tree bark, etc.

Only the licensed Template:Taxobox

Psocoptera are an order of insects that are commonly known as booklice or barklice. They first appear in the Permian era, 295-248 million years ago. The are often regarded as the most primitive of the hemipteroids. Their name originates from the Greek word psokos meaning gnawed or rubbed and ptera meaning wings. There are roughly 3,000 species in 35 families in 3 suborders.

They range in size from 1 to 10 mm in length.

No member of this order is currently at conservation risk.