Monolepta beetle (red - shouldered leaf beetle)
The beetles are 6 mm long and yellow, with a dark red (purple) band across the shoulders and two purple spots on the ends of the wing covers. The flaccid yellowish eggs are small (less than 1 mm across) and oval. The larvae are white, slightly flattened with hard brown (sclerotised) plates at both ends, and reach 10 mm in length.
Similar: The adults are easily distinguished from other beetles by their distinctive colouration.
Distribution: Throughout northern Australia and particularly in cane-growing coastal regions such as Bundaberg.
Crops attacked: Adults feed on many types of plants. Of the summer legumes, soybeans, navy beans and mungbeans are particularly attractive hosts. Other crops include cotton, sugarcane and pasture grasses. Larvae feed underground on the roots of sugarcane and pasture grasses.
Damage: Adult beetles attack leaves and flowers. High populations (e.g. 50 per square metre) will shred leaves and denude crops of flowers.