Town lays carpet of killer weed
OUR CORRESPONDENT
Sonitpur
A parthenium plant

Feb. 6: A weed that causes respiratory distress in humans and
livestock has spread to nearly 80 per cent of Tezpur town, but the
municipal authorities remain blissfully unaware of the health hazard.

Parthenium, or parthenium hysterophorus, is one of the deadlier weeds
around and was actually "imported" by India along with the PL 480
Mexican wheat seeds in 1956. It has since become an uncontrollable
menace, spreading rapidly in parks, residential colonies with an
abundance of shrubbery and rail tracks. The monster weed is known to
cause skin allergies, hay fever and asthma in human beings and is
toxic to livestock. Left to spread, it also squeezes grasslands,
reducing the supply of natural fodder for cattle.

Parthenium was spotted for the first time in Tezpur nearly 21 years
ago. What was then just a patch near Dekargoan railway station has
since become a blanket of weeds covering almost the entire town.

The Tezpur Municipal Board may be focused on turning the town into a
tourist desitination, but has yet to do anything about the weed
menace. "If the spread of this weed remains unchecked, residents of
the town will be in serious danger," a botanist based in the central
Assam town said.

Some NGOs have, however, woken up to the menace and chalked out plans
with the support of residents to rid the town of parthenium growth.
Volunteers have already uprooted parthenium weeds from the campuses of
Darrang College, Tezpur College and the Dak Bungalow.

"Just because the administration has not taken any step, we cannot be
idle as well. The health of an entire town is at stake," a member of
one of the NGOs said.

Parthenium belongs to the Asteraceae family and is locally known as
pandhari, Congress grass or carrot weed. One of the ways to control
the weed is to go for uprooting before it flowers. In 2005, the
National Research Centre for Weed Science, which operates under the
Indian Council for Agriculture Research, began a campaign for
biological control of parthenium through beetles imported from Mexico.

Mexican beetles (zygogramma bicolorata) are considered a safe
biocontrol agent. The larvae feeds on parthenium leaves for 10 to 15
days, enters the soil on maturing and pupates. The beetles emerge
after a maximum of 12 days and complete their life cycle in a range of
27 to 32 days.

Since both adults and larvae feed on parthenium, they check plant
growth and flowering. Adults defoliate the plant.

Immature flowers are cut by the beetles to chew on the soft tissues
beneath the flowers. Completely defoliated plants wilt in no time.

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