PM Shri Kendriya
Vidyalaya Lekhapani
Tinsukia , Assam (786182)
Biology Investigatory Project
Different Invasive Weeds and their impact in India
Session – 2024-25
Submitted To Submitted By
Ms. Jyoti Verma. Sumi Chetry
PGT BIOLOGY Class XII-A
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CERTIFICATE
This is to certify that this investigatory project on the
topic - Different Invasive Weeds and their impact in
India has been successfully completed by Miss Sumi
Chetry of class 12th Science under the guidance of Miss
Jyoti Verma in particular fulfillment of the curriculum of
Central Board of Secondary Education (CBSE) leading to
annual examination of year 2025.
Signature of Signature of Signature of
Principal External Invigilator Subject Teacher
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ACKNOWLEDGEMENT
I would like to express my gratitude and appreciation to everyone who
has contributed to the completion of my biology project. I would like to
acknowledge my biology teacher Miss Jyoti Verma for providing me
with guidance and support throughout the process. Without her
knowledge and expertise, it would have been difficult for me to gather
accurate information and conduct a thorough analysis.
I would also like to extend my gratitude to our principal Mr. Akhilesh
Kumar Chaudhary for giving me a chance to work on this project.
Additionally, I would like to thank my classmates for their valuable
input and suggestions during our group discussions. Everyone’s
contributions have played a significant role in the successful completion
of this project, and I am truly grateful for their assistance.
Sumi Chetry
Class – 12th Science
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INDEX
Sl. PAGE
TOPIC
no NUMBER
1 Introduction 05
2 Effect of Invasive Weeds in India 06
3 Some of the main harmful Invasive 07-12
Weed species in India –
Lantana camara
Water hyacinth (Eichhornia crassipes)
Parthenium (Parthenium
hysterophorus)
Cyperus rotundus
Mikania micrantha
4 How to prevent the harmful weeds 13
Control Mechanisms
5 14-
15
6 Conclusion 16
7 Bibliography 17
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Introduction
Invasive species - An invasive species is an organism
that is not indigenous, or native, to a particular area.
Invasive species can cause great economic and
environmental harm to the new area. An invasive species,
also known as an exotic species.
Invasive weeds are non-native plants that aggressively
spread and outcompete native species in an ecosystem.
They often lack natural predators or controls, allowing
them to dominate landscapes and disrupt biodiversity.
Invasive weeds can cause ecological harm by altering
habitats, reducing crop yields, and increasing erosion.
Managing these plants requires strategies such as
mechanical removal, chemical control, and biological
methods to restore balance to affected ecosystems.
Lantana camara Water hyacinth
Effect of Invasive Weeds in (Eichhornia crassipes)
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India
Invasive weeds in India disrupt ecosystems, agriculture,
and human health. They outcompete native plants,
reducing biodiversity and altering habitats. Agricultural
productivity suffers as they consume nutrients, water, and
sunlight meant for crops. Invasive species like water
hyacinth clog waterways, hindering transportation and
exacerbating flooding. Some weeds, like Parthenium,
cause allergic reactions and respiratory issues in humans
and livestock. Controlling these weeds requires significant
resources, including herbicides and manual labour. Failure
to manage them can lead to economic losses and
environmental degradation, underscoring the critical role
of invasive weed management in India's sustainability
efforts.
So
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me of the main harmful
Invasive Weed species in
India
1.Lantana camara –
They were brought to India by the Britishers around
200 years ago, which then spread and became
invasive here as well.
It impacts severely on agriculture as well as on
natural ecosystems.
It produces large numbers of seeds that are
dispersed by birds and the seeds germinate rapidly
and easily. Under conditions of high light, soil
moisture and soil nutrients Lantana is a very efficient
competitor against native species.
Lantana is widely reported to be poisonous to cattle,
buffalo, sheep, goats and horses.
It reduces the productivity in pasture through the
formation of dense thickets, which reduce growth of
crops as well as make harvesting more difficult.
It releases allelochemicals like phenolic compounds
or flavonoids that may suppress the regeneration
process of indigenous plant species by decreasing
their germination and seedling growth and increasing
their mortality.
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Management –
A three phase integrated strategy developed for its
management could be practiced:-
Phase 1: Cut the Lantana bushes up to 5-8 cm above
the ground level between August and October months.
Phase II: Spray glyphosate(0.75-1%) solution on
regenerated foliage during September to November
months.
Phase III: Plant competitive species such as guinea
grass (Panicum maximum) or any fast growing fodder
tree like robinia or poplar tree as per the land
suitability.
2. Water hyacinth (Eichhornia crassipes):
This is not an indigenous species but was introduced
to India during the British colonial rule as an
ornamental aquatic plant from South America.
It is a floating plant that has clusters of leaves with
spongy stalks arising from a base of dark purple
feathery roots.
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This aquatic plant grows rapidly, forming dense mats
on water bodies, which can block sunlight and
oxygen, leading to the death of aquatic life.
Water hyacinth prevents the growth and abundance
of phytoplankton under large mats, ultimately
affecting fisheries.
Management –
Manual removal of water hyacinth using mechanical
mowers, dredgers or manual extraction methods, is
probably the most widely practiced method of control
in developing countries.
Control with glyphosate at 2.20 kg/ ha was more
effective with least effect on water quality and fish
mortality.
Eichhornia
crassipes
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3. Parthenium (Parthenium hysterophorus):
Parthenium or Gajar Ghans (Carrot grass) is the most
widely recognized invasive species in India.
It was introduced into the Indian sub-continent to
Sind province (Pakistan) in 1877 from South America,
and later on it was introduced into many dry regions
of India.
The plant produces allelopathic chemicals that
suppress crop and pasture plants, and allergens that
affect humans and livestock.
It also frequently causes pollen allergies.
The weed is unpalatable to livestock so its invasion
results in grazing shortages.
Management:-
Biological control of Parthenium using Zygogramma
bicolorata, a Mexican beetle has been found very
promising.
Competitive plant species like Cassia sericea, C. tora,
Tagetus erecta, and Abutilon indicum in noncrop
areas is recommended for control of the weed.
To control this weed, it is recommended to pull out
the plants before they flower, making sure to remove
all of the root system to avoid regrowth from root
remnants.
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Parthenium
hysterophorus
4.Cyperus rotundus :-
It is a species of sedge (Cyperaceae) native to Africa,
southern and central Europe (north
to France and Austria), and southern Asia.
Cyperus rotundus (Cyperaceae) is one of the
problematic weeds that affect the growth and
production of rice (Oryza sativa ), sugarcane
(Saccharum officinarum ), cotton (Gossypium spp.),
maize (Zea mays)
Cyperus rotundus is one of the
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most invasive weeds known, having spread out to a
worldwide distribution in tropical and temperate
regions. It has been called "the world's worst weed”
The growth of Cyperus rotundus can alter the soil
structure, leading to the formation of dense mats of
roots and tubers. This can negatively impact the
aeration and drainage of the soil, affecting the
overall health of plants.
Cyperus
rotundus
Management:-
spraying of Glyphosate efficiently managed the weeds
under non cropped land.
5. Mikania micrantha:
Mikania micrantha is a tropical plant in the
family Asteraceae; known as bitter
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vine, climbing hemp vine, or American rope
Mikania micrantha was introduced into India after
the Second World War to camouflage airfields.
Mikania micrantha is an economically damaging
invasive weed, which is widely naturalized in the
tropical and subtropical regions of the world.
This weed has reported yield losses in various
cash crops and plantation crops in South East
Asia including India.
M. micrantha was found to change the soil
microbial communities (bacteria, fungi and
actinomycetes) as well as the soil chemical
properties.
It was also found that the aqueous leaf extract of
invasive weed M. micrantha inhibited seed
germination and seedling growth of various
cereals, vegetables, and other plants.
Management:-
Integrated approach involving mechanical,
chemical and biological methods is required to
manage control this weed.
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Mikania
micrantha
How to prevent the harmful
weeds
1. Education and Awareness: Educate communities,
farmers, and gardeners about the importance of identifying
and controlling invasive weeds.
2. Use of Native Plants: Promote the use of native
plants in landscaping and agriculture, which are better
adapted to local conditions and less likely to become
invasive.
3. Quarantine Measures: Implement strict quarantine
measures on imported plants and seeds to prevent the
introduction of invasive species.
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Control Mechanisms –
There are various methods used for the control and
management of invasive species:
Biological control is the intentional manipulation of
natural enemies (biocontrol agents) by humans for
the purpose of controlling invasive plants reducing
the population . Natural enemies used in classical
biological control of weeds include different
organisms, such as insects, mites, nematodes.
Chemical control includes the use of pesticides,
herbicides, fungicides, and insecticides. Although
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chemical use can be very effective, they can be
dangerous to other species or to the ecosystem in
general. Chemical control may be difficult,
expensive, and create concerns about environmental
health.
Cultural control includes manipulation of habits to
increase mortality of invasives or reduce it's its rate
of damage (selection of pest-resistant crops, winter
cover crops, changing planting dates). Cultural
practices include mulching, soil solarization with
plastic film, thermal weed control (e.g., flaming, hot
water, and steam), prescribed burning, water
manipulation, and prescribed grazing with
domesticated herbivores (e.g., cattle, sheep, goats,
and horses).
Mechanical control techniques include mowing,
hoeing, tilling, girdling, chopping, and constructing
barriers using tools or machines to "harvest" invasive
plants by removing and collecting them, and
transporting elsewhere and allowing them them to
decompose in place.
Physical or manual control involves physical
activities (i.e. harvesting) such as hand-pulling,
digging, flooding, drawdowns (de-watering),
dredging, mulching, manual destruction or removal
of nests, egg masses, or other life stages, or shading
to control invasive plants.
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Conclusion
Invasive weeds pose a significant threat to ecosystems,
agriculture, and human health worldwide. Their aggressive
growth outcompetes native vegetation, leading to
biodiversity loss and habitat degradation. Economically,
invasive weeds can cause substantial damage to crops,
resulting in yield losses and increased management costs
for farmers. Additionally, they can impact water quality,
hinder recreational activities, and even pose fire hazards.
Effective management strategies, including early
detection, rapid response, and coordinated control efforts,
are crucial in combating invasive weed species.
Prevention through stringent regulations on the
importation and movement of potentially invasive plants is
also essential. Public awareness and education
campaigns play a vital role in encouraging responsible
plant cultivation and disposal practices to minimize the
spread of invasive weeds. Ultimately, addressing the
threat of invasive weeds requires collaborative efforts
across government agencies, researchers, land
managers, and the general public to protect ecosystems
and promote environmental sustainability.
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Bibliography
The contents for this project has been referred from
following sources :
Books –
NCERT CLASS XII Biology book
Websites –
http://nbaindia.org
https://www.upsbdb.org
http://envis.nic.in
https://www.nationalgeographic.org
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