Beware of this weed

By Dr. A.H. Magdon Jayasuriya

A farm manager of the Government Seed Farm in Vavuniya has been affected by dermatitis caused by this noxious weed.

Mr. Thiruchittampalam, a dedicated and hard-working agriculturist, begins his day at six in the morning with a walk round the farm to inspect the crops. 

Being a farmer through and through, Thiruchittampalam has the habit of walking barefoot with his trousers rolled up to his knees. This has been his way of life for the last one and half years and he now suffers from severe itching. 

The rash is clearly visible with cracks on the skin of his weather-beaten legs.

In India and Australia, the parthenium weed (Parthenium hysterophorus, a member of the sunflower family) is feared for its adverse effect on agriculture, the environment and human health. The plant causes acute allergic dermatitis in humans, which after continuous exposure becomes chronic. A chemical compound known as "parthenin" in the plant is the causative agent for this reaction and highly sensitised individuals are advised to avoid contact with the plant. 

In some situations, the situation can become so bad that landholders and other workers are forced to move from the district or cease their normal activities. Up to 10 per cent of people living in parthenium- affected areas in India suffer from allergic rhinitis and sinusitis (hay fever). 

The parthenium pollen causes these problems and observations in Bangalore have indicated that the increase in the incidence of nasobronchial allergy among locals is associated with the widespread growth of parthenium. 

As earlier newspaper reports indicated, the introduction of this invasive weed species into Sri Lanka is associated with the arrival of the Indian Peace Keeping Force in 1987. 

However, there is also evidence that subsequently it was brought here with chilli and onion seed imported from India.

Since its discovery in Vavuniya in July 1999, the presence of this noxious weed has been reported from several locations in the Jaffna peninsula, Mullaitivu, Trincomalee, Polonnaruwa, Kurunegala, Kandy and Badulla districts. 

The spread of the parthenium weed has taken a new turn with its seed originating from a large population of this plant in Kandaketiya (Badulla District) spilling into the Mahaweli below Randenigala. 

The recent reports of its occurrence in Badulla and Bandarawela is evidently due to the presence of its seed in sand transported from the Mahaweli.

As the disastrous effects of parthenium weed on agriculture, environment, human and animal health are well known in India, Australia, Mexico and the Caribbean etc., immediate action should be taken to control its spread in Sri Lanka. 
Weed out that weed

The Department of Agriculture is coordinating an action plan to detect the parthenium weed problem in Sri Lanka and requests information from the public on its occurrence in various areas. 

The Department is also providing advice on the control of the weed. Pamphlets containing colour pictures and information on the weed could be obtained from the Plant Protection Division, Department of Agriculture, Gannoruwa, Peradeniya (08-388316). Specimens may also be sent for verification to the Plant Genetic Resources Centre, Gannoruwa, Peradeniya (08-388490, 388494).

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