Lesser Grain Borer

Rhizopertha dominica

Family: - Bostrichidae

Order: - Coleoptera


Adult -

Colour - Rust red.

Body - 2.5-3 mm by 1 mm wide and cylindrical.

Wings - Elytra striate and rounded apically. Striae punctulate.

Mouthparts -

Antennae -

Legs -

Head -

Thorax - Pro thorax tuberculate

Abdomen - Square on the head end and with a rounded tail.

Egg - White and pear shaped.

Habits -

Larva - About 5 mm long.

Colour - White with a brown head.

Body -

Mouthparts -

Antennae -

Legs -

Head -

Thorax - Broad thoracic segments.

Abdomen - Caudal end narrow and curved.

Habits -

Pupa - Yellowish white. 3 mm ling by 1 mm wide.


Life Cycle:

The female lays eggs singly or in groups. The young larva feed on grain dust. Older larvae penetrate intact grains and hollow out the centre leaving an empty husk. Females lay 300-500 eggs and the life cycle takes 65-70 days at 260C and 70% relative humidity. The beetles fly on warm days and may attack grain in the field.


Origin and History:




It attacks most cereals including Wheat, Barley, Rye, Corn, Sorghum and some pulses such as Beans. It will also attack some processed products like biscuits and raw hides.

It is mainly a pest of tropical and subtropical areas and rarely becomes a problem in cool climates.

Management and Control:

Fumigation is often used.

Methoprene is particularly effective on Lesser Grain Borer but some populations are resistant.

Spinosad is effective on most resistant populations 1221.

Related Species:

Granary Weevil (Sitophilus granarius)

Rice Weevil (Sitophilus oryzae)

Rust-red Flour Beetle (Tribolium castaneum)

Sawtoothed Grain Beetle (Oryzaephilus surinamensis)

Similar Species:


CSIRO. The Insects of Australia. Melbourne University Press. (1991)

WADA. Insects and Allied Pests of Extensive Farming. Department of Agriculture - Western Australia Bulletin No. 4185.

Avidov, Z. and Harpaz, I. (1969) Plant Pest of Israel. Israel University Press. P


Collated by HerbiGuide. Phone 08 98444064 for more information.