General 
The adult is an active, slim-bodied , dull reddish brown beetle between 2.5mm –3.5mm in length. The thorax has 6 distinct teeth on each margin giving a saw-like  edge. Wings are well developed. Adults can fly and are attracted to light. It resembles the saw-toothed grain beetle. Care is needed with identification. The larva is yellowish white and has a brown head with 3 pairs of thoracic legs and a pair of abdominal prolegs.  
                         
Significance
In the UK, established only in heated buildings. Occurs on a wide variety of foodstuffs and is a pest of oil seeds and their products rather than cereals and cereal products. It is also found on dried fruits, nuts, coconut and confectionary and will bite through food packaging.

Control
Infested commodities should be isolated and destroyed, or failing this fumigated.
The structure and fittings of the infested area should be treated with a residual insecticide. This treatment may be supplemented with the use of an ultra-low volume insecticide application.

Number of days spent as:

Top: Oryzaephilus mercator adult

Bottom: Head shapes of O. mercator and O. surinamensis