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Psocids (Booklice)

Image of psocid also known as booklice Psocids (pronounced so-sids) otherwise known as booklice are tiny grey/brown insects between 1-2mm long which can be found in or around dry foods such as flour, sugar, semolina and powdered milk.

They are not caused by poor hygiene and are just as common in clean homes both old and new. They prefer to live in dark, warm, humid places e.g. folds of packaging in food cupboards, and they dislike light and disturbance. They feed on a variety of food, such as flour, and live for approximately 6 months during which time the female may lay up to 100 eggs.

Psocids are often found in kitchens where fitted cupboards and food products provide the moisture and darkness that attracts them. They increase rapidly in warm conditions so summer/autumn is the time of year they are likely to be discovered.

Preventing psocid infestations

  • Keep all dry foods in cool, ventilated cupboards.
  • When condensation occurs in your kitchen (during washing or cooking) open the windows or use an extract unit.
  • Packages of food that have been opened should be used up quickly.
  • Potential hiding places should be sealed with paint or mastic.
  • Clean kitchen cupboards regularly to remove dry food from crevices, but do not make chipboard wet as this may encourage mould growth. Use a vacuum cleaner and dispose of the contents immediately in an outside waste bin.

Control of psocids

If you discover psocids in your food:

  • Do not use insecticides because of the danger of contaminating food.
  • Dispose of all infested packages in an outside waste bin.
  • Thoroughly clean the cupboards using a vacuum cleaner.

When replacing foodstuffs, after cupboards have been cleaned, ensure they are not re-introduced.

  • Place dry goods in a plastic bag in the freezer for 24 hours to kill any eggs or juveniles that may be hidden in the folds of packaging.
  • Remove labels from tinned food, bottles and jars to prevent psocids hiding behind the paper (note: mark the contents of the tin, jar or bottle with a felt-tip pen).
  • The freezer treatment (in a plastic bag) is also suitable for books or other objects which may harbour psocids or their eggs.

If the problem persists, contact |Environmental Services.


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