Pest of the Month: called booklice — it’s the pantry pest
Households within the Horowhenua region occasionally encounter an insect which is capable of accessing food storage cupboards and pantries.
This is the psocid (pronounced so-kid). Psocids are tiny insects, averaging 1-2mm in size and tend to be overlooked. Microscopically they may resemble tiny termites, however, to the naked eye they can appear as moving carpets of brown dust, swarming over shelves and food. While seemingly not one of those pests that pose a great risk, numbers can quickly multiply resulting in a massive population explosion, particularly in damp, warm environment.
In the pantry, psocids flourish on grains, bran, cereal, breakfast foods, dried fruits, nuts, crackers, cookies and dried pasta. They are commonly found inside an opened bag of flour. Any manufactured material of plant origin is susceptible to a psocid attack. What is really interesting is instead of actually eating these food items, the psocids are actually grazing on all the microscopic moulds and mildews found growing on the surface of these products.
Psocids are often referred to as booklice, book ticks or dust lice, however, they are neither lice nor tick. The name ‘booklice’ comes from the fact that they are also frequently found in libraries or more often where old books are stored. Psocids do not attack the books directly. Instead once again they feed on moulds and fungi that are growing on the books themselves. How is this so? As paper is sourced from wood, and wood, being plant derived, it attracts the growth of moulds. The glue the binds the pages is also tempting. It is often manufactured from plant-derived cellulose, and once again it is the moulds growing on the glue that the psocids are gorging on.
Depending on temperature (10-25 degrees C) and relative humidity (greater than 50 per cent), most psocids can produce two or three generations annually. Eggs hatch in two to four weeks. They go through two to four nymphal stages, taking up to three months, before reaching maturity. Once mature, females can generate 50-100 eggs during a lifetime. Adults have a lifespan of approximately five months. They also have a surprising ability to survive in adverse conditions and without food.
How to control psocids? It’s easy — the key is to ensure a low humidity environment within the house, pantry or areas where psocids are located. For example, when cooking, humidity is likely to build up in the kitchen/pantry. To reduce the humidity level, ensure there is adequate ventilation — open a window. It is also important to check cupboards regularly, store food products in closed containers and use any plantderived food products before ‘use by’ dates. If an infestation occurs in a cupboard, try using a hairdrier to dry the area out. Try to ensure it stays dry and once again, has plenty of air circulation. If you can keep the humidity low, psocids are less likely to reinfest.
Brent Page is a Horowhenua entomologist and Director of Nature’s Way Pest Control. For more information, visit www.nwpc.co.nz