LANDHOLDERS are urged to be on the lookout for noxious weed, wild tobacco, after cattle were recently killed after grazing on the plant in south-west Queensland.

Cattle on the stock route Keebrah Reserve, Bollon-Dirranbandi Rd, ingested the plant, resulting in 50 head dying from the plant which is toxic to both livestock and humans if eaten in sufficient quantities.

Balonne Shire Council rural services manager Karl Hempstead said landholders adjacent to the reserve had been contacted and asked to take measures to prevent infestation on their properties.

Council has also used herbicide control at the affected site.

People are urged to report sightings of the plant to the Balonne Shire Council Rural Services Department on 0429 208 861.

Wild tobacco (Solanum mauritanum) shrubs grow to four metres in height.

Its leaves are up to 30cm long and 10cm wide, yellowish-green in colour and paler underneath with felt-like hairs.

Flowers are lavender-blue with yellow stamens and are present in autumn to spring.

The plant's fruit is small, 10-15mm wide, and turn green to yellow as they ripen.

The plant originates from Argentina in South America.

All parts of the plant are poisonous to humans, particularly the green berries. Wild tobacco is a coloniser of disturbed sites and also found along roadsides, waterways and waste areas.