‘S American weed harming crops, animals, humans’

* Reports find parthenium carries toxins, leaves adverse impact on
rice and maize
* Say weed is a source of allergy and skin disease

By Atif Khan

ISLAMABAD: Aggressive growth of parthenium weed, an alien species, in
the capital is harmful to indigenous plants and a source of allergy,
according to research reports.

The reports say parthenium weed is of South American origin and was
accidentally introduced in South Asia in 1955 through imported food
grains. Its plants flower after just one-two months and these flowers
stay for several months. A single plant can produce 15,000-25,000
seeds, which travel in air and result in its extensive growth.

Different studies have concluded that parthenium has very negative
impact on local flora and fauna and it creates health problems in
humans and animals. Asad Shabbir, a lecturer, and Dr Rukhsana Bajwa, a
professor at the Punjab University (PU), have jointly published a
research paper on this weed.

Adverse impact: The paper recognises the species as one of the major
threats to native species and ecosystem. Parthenium weed is spreading
throughout Pakistan and is known as one of the most troublesome weeds
worldwide, it says.

It says the weed’s adverse impact on humans, livestock, crops, and
biodiversity has been proven and the data show that the population of
many common medicinal plants in the capital is rapidly declining
because of the invasion of parthenium.

Health risks: Another research carried out by P Oudhia, the Society
for Parthenium Management (SOPAM) convener, says, “Chemical analysis
of this weed has indicated that all plant parts including trichomes
and pollens contain toxins called sesquiterpene lactones.”

It says, “The major components of toxins are Parthenin and other
phenolic acids and are lethal to human beings and animals.”

Himalayan Foundation has reported, “Invasive species are one of the
major causes of destruction of local vegetation and wildlife of the
Margalla Hills. Over 30 percent of it has been destroyed completely
and another 30 percent is being destroyed. This heavy damage not only
poses a threat to wildlife but has also resulted in depletion of
underground water resources.”

The Pakistan Medical Journal has reported parthenium invades crops
like rice and maize and causes skin diseases in humans. Out of a study
sample of 511 patients, 391 developed skin allergy from parthenium.

It adds that the weed has spread to Lahore after Rawalpindi and
Islamabad and this rapid spread is probably due to its use in bouquets.

Mazhar Hussain, the Capital Development Authority CDA director-general
(environment), told Daily Times that invasive species had spread
drastically in the capital and paper mulberry is the most harmful of
them all.

He said the invasive species were hard so they replaced local species
easily. He said alien plants should be cut off but it was a very hard
task to complete.

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