Psocids are insects that congregate in large numbers on outdoor ornamental plants and trees where they feed on fungi, lichen, pollen, decaying plant debris, and other organic materials. While psocids do not inflict damage to plants, they are considered minor pests due to their occasional abundance in residential yards where they can pose a nuisance to homeowners. Most psocid species dwell solely outdoors, and the outdoor species that occasionally become problematic pests in residential yards are commonly referred to as “barklice.” A small minority of psocid species are known for congregating within homes, sometimes in tremendously large numbers where they frequently inflict property damage by eating holes in paper and adhesive in bookbinding. Barklice possess functional wings, while indoor psocid pests are wingless and commonly known as “booklice.” Just like barklice, booklice feed on mold in high-moisture conditions, and their presence within homes often leads to the discovery of dangerous mold and fungal organisms. In rare booklice infestation cases, the tiny pests find their way into food packages within pantries.
A psocid has a white, gray or brown-colored body that is very soft and minute at less than 3/16 of an inch in length, but their lengthy antennae make them easy to recognize. In addition to their noticeably slender antennae, psocids have a conspicuously large nose called a “clypeus,” and most psocid species are noticeably swift and rapid in their movements. Booklice always congregate in warm and damp areas where moisture content is sufficient to support the growth of fungi that they rely on for sustenance, but they are also known for consuming crumbs, insect fragments, starchy materials, and damp paper. Unsurprisingly, booklice are often found consuming wet cardboard boxes, especially when they contain damp paper materials like newspaper or books. Booklice commonly gravitate toward wet plaster, condensation on walls, and leaking pipes. Reducing the relative humidity to 45% – 50% within a home will make conditions inhospitable to booklice, and a dehumidifier is often necessary to dry-out isolated indoor locations that have accumulated moisture and consequent mold.
Have you ever encountered booklice within your home?