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Durban Early Detection and Rapid Response

Famine Weed Parthenium hysterophorus

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Common Name
Famine Weed
Classification
CARA Category 1
NEMBA 1b

Parthenium weed originates from North America and belongs to the Asteraceae family. It is an annual herb that grows between 0.3m to 1.5m tall, with an erect longitudinally grooved stem and a deep tap root. The stems and leaves have short hairs, and the leaves are pale green in colour. The rosette and lower stem leaves are also pale green and are deeply pinnately lobed. The flowers are white, about 3mm across, in small compact heads and are produced from September up until May. Seeds are black.

Why is it a problem?
The presence of Parthenium Weed poses a major health hazard, since it is a nerve depressant and produces allergenic dermatitis and asthma in humans. It spreads by seeds that can be viable for many years and is browsed by stock. Cattle that have consumed Parthenium Weed are not fit for human consumption and their milk may become toxic.
Control method
Parthenium Weed is typically kept under control by using mechanical and chemical removal. Spraying with a selective herbicide so that other species are not killed is highly recommended. Treated areas should be closely monitored for up to seven years so that outbreaks do not occur. Parthenium Weed has already been subjected to biological control in Australia, where nine insect agents and two rust fungi have been successfully established. It is hoped that cooperation with Australian researchers will help to ‘fast track’ the control of this plant in South Africa.
Where is it a problem?
This is found in KZN and Swaziland.

Identifying other species

For help with identifying other species, submit your photo and observations to
iSpot: www.ispot.org.za

The iSpot experts may be able to provide a name.

 

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