Merchant Grain Beetle
Key Features
Merchant Grain Beetle (Oryzaephilus mercator) are small oblong shaped insects that are dark brown in colour, and are about
2 - 3 mm in length, they are very similar in appearance to the saw-toothed grain beetle, with 6 saw-like projections on each side
of the thorax. In contrast to the Saw-toothed grain beetle, the merchant grain beetle flies readily.
In the UK, The merchant grain beetle can infest a variety of foodstuffs, such as cereals, cornmeal, cornstarch, popcorn, rice, dried
fruits, breakfast foods, flour, rolled oats, bran, macaroni, sugar, drugs, spices, herbs, candy, dried meats, chocolate, bread, nuts,
crackers, raisins, dried dog and cat food. They prefer foods with a fat content.
Biology
Merchant grain beetles lay an average of 200 eggs over 28 to 42 days, requiring about 35 days to complete the life cycle.
There may be as many as 6 to 7 generations under warm conditions of 85 degrees F to 95 degrees F and 70-percent relative
humidity, with fewer generations throughout the winter months. Adults remain active and feed.
Distribution
World-wide tropical and temperate distribution.
Significance
As a result of it's relative intolerance of low temperature and humidity O. mercator is not one of the principal UK stored product
pests. It is present in large-scale numbers only within heated buildings in Britain.
Control
Good hygiene practices, and quarantine of inbound goods is recommended. Monitoring products and systems may be used to
time treatments to best effect. Treatments may include Atmosphere control, temperature control, and Fumigation / use of residual
insecticides where appropriate.
