Name
Latin name
Tribolium confusum
Key features
The adult beetle length is 3 to 4.5 mm.
The shape is elongated; the antennae have a gradual five-segmented club.
It is easily mistaken for Tribolium castaneum, the rust-red flour beetle, which has distinct threeclubbed antennae.
The cylindrical wiry larva is 4 to 5 mm long when fully grown and is white tinged with yellow. It has a pair of immovable projections, urogomphi, on the final abdominal segment.
Biology
The female lays 500 to 1000 eggs, producing 2 or 3 per day. Eggs are deposited in the food material.
Adults frequently congregate in large numbers along the folds of food packaging.
Although these beetles have wings, they fly rarely if at all.
At the optimum temperature of 32.5ºC the life cycle takes 4 weeks. Development proceeds between 21ºC and 33ºC; the minimum relative humidity required is 1%. Under ideal conditions, populations may increase 70 times per month.
In common with other insects, development times are influenced by temperature, relative humidity, moisture content, quantity and quality of food. The following figures are therefore only a guide.
Number of days spent as:
Egg: 4 – 30
Larva: 15 – 98
Pupa: 5 – 22
Adult female: 435
Adult male: 540
Distribution
African in origin but now spread throughout the world in regions suitable for its temperature requirements.
Significance
It is one of the most common beetle pests of stored products, a major pest of cereals in particular.
A very common pest in flour mills in the UK.
It has been recorded on peas, beans, spices, drugs, chocolate, dried fruits, groundnuts and bones.
These beetles are unable to feed on undamaged grain.
Control
Any infested commodities should be isolated and destroyed.
The structure and fittings of the infested area, bases of equipment, pallets, cracks and crevices should be treated with a residual insecticide.
This treatment may be supplemented with the use of an ultra-low volume insecticide application.
The use of Tribolium monitoring traps to determine the level and extent of infestation may be helpful.