Scientific name: Oryzaephilus surinamensis
There are 3 different species:
1. Oryzaephilus surinamensis (dark brown beetle)
2. Oryzaephilus Mercator (Flat bark beetle)
3. Ahasverus advena (foreign grain beetle)
The grain beetle is a small insect with a slender, long body. It will typically reach 2.5-3.5mm in length. It is a dark brown or reddish-brown colour with a distinctive 11-segment clubbed antenna.
Originating from the Americas, this species is now cosmopolitan in distribution.
The grain beetle will inhabit grain at any point during processing, so are as common in farm storage as they are in retail storage. They are small active insects which readily exploit cracks and crevices where they can hide.
One of the most common pests affecting stored grain products, it is a cold-hardy insect that can overwinter in temperate lands. The life-cycle completes in as little as 20 days and serious outbreaks may occur within a month of harvest.
Infestations often occur when grain is being transferred or in the fabric of grain stores (including sacks), and in vehicles used for transporting.
Small numbers of insects can rapidly give rise to serious infestations. The species will infest cereals and a wide range of foodstuffs; they frequently appear in packaged foods.
Generally, they infest damaged grains and use small lesions in the grain to attack it. Their presence in grain may result in its rejection.
The foreign grain beetle is capable of infesting a variety of materials but only in the presence of moulds.