Biology

An annual weed, reproducing by seeds. This weed grows especially in areas of fine textured soils. The stems are erect, to 1 m tall, smooth, and branched with swollen nodes. The leaves are opposite, 2-8 cm long, smooth, sessile, and blue to green in colour. The flowers have 5 petals united to form a calyx, funnel-shaped, pale red to deep pink, and loosely grouped at the ends of stems. The seeds are round, 2 mm in diameter, rough, black, and enclosed in a capsule. All plant parts especially the seed contain the toxic substance saponin which is poisonous to livestock.

Scouting Techniques

Take a minimum of 20 weed counts across the field.

Effects on Crop Quality

Resistant to herbicides commonly used for control. This enables the weed to thrive in cropped land where other weeds are controlled by these chemicals and reduce yields as a result of competition.

Control Tips

• resistant to Group 4 herbicides (2,4-D and MCPA)
• Group 9 & 10 in herbicide tolerant crops