Ragwort [Jacobaea vulgaris]

Pest Profile

About the weed

It is a medium-tall, hairless biennial, not very branched, with a basal rosette of grey-green, roundly divided leaves. The flowerhead has groups of yellow daisy-like flowers.

Key features

Plant: The plant contains the poison Jacobine, which is fatal to livestock.

Biology

Ragwort can be abundant in poor pasture and wasteland, particularly on sandy freedraining soils. It is rarely found as an arable weed, but does establish in fallows and field margins. Seedlings germinating in autumn can overwinter as leafy plants. The plant may take more than two years to flower. Seed is not dispersed far from the parent plant, but can survive grazing and can be transported by sheep. The flowering shoots die by winter.

Symptoms & Diagnosis

Life Cycle

Seed longevity: >5years
Seed weight: 0.2 mg
Seeds/head or capsule: 100
Seeds/plant: 50 000 - 60 000
Seed weight: 66.67 mg

Treatment

Management

Dense grass swards which are not over-grazed reduce establishment. In grass, MCPA or 2,4-D may be used at full dose on the rosettes in late spring or early autumn.