Brown bean bug

Adults are brown and elongated, with long antennae and robust, spiny hind legs.

• LBBB has a bright yellow stripe along each side (paler in females), and a prominent spine on each shoulder.
• SBBB has a cream stripe along each side (males also have a pale patch on the upper back) and smaller shoulder spines.

Eggs are slightly elliptical with a flat top and laid singly or in small clusters.

• LBBB are dark purple-brown and 1.5mm long
• SBBB are shiny olive green and 1mm long.

Nymphs are dark brown and are similar in outline to ants. The abdomen of later instar SBBB is more elongated than LBBB.

Nymphs can be mistaken for ants, but lack the very narrow 'waist' and biting mouthparts (jaws).

Native to Australia; they are widespread in warmer areas.

All summer and winter pulses (except chickpeas).

• LBBB prefers mungbean, cowpea and adzuki bean.
• SBBB favours soybean.

A minor pest in cotton and many horticultural crops.

Damage symptoms are similar to those of the green vegetable bug (GVB). Early damage reduces yield, while later damage reduces the quality of harvested seed.

• Adults typically invade summer legumes at flowering.
• Under laboratory conditions, individual females can lay 5–6 eggs per day.
• Nymphs usually reach a damaging size by mid to late podfill.
• Development time from egg to adult (through 5 nymphal stages) is about 25–26 days.
• Overwintering LBBB may shelter in curled-up, dead leaves.

Beat sheet counts may underestimate numbers as adult bugs are very flighty—monitor crops early morning and watch for adults flying away.

Podsucking bugs other than GVB are converted to GVB equivalents, and decisions are made based on the GVB thresholds. An online calculator for mungbean and edible soybean is available at the Beatsheet.

Brown bean bugs may be incidentally controlled by products used against the green vegetable bug. There are no products registered specifically for brown bean bugs in pulse crops.