Error! Filename not specified. Biological Control of Parthenium What is parthenium? Why parthenium is a dangerous weed? What i...
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Filename not specified.
Biological Control of
Parthenium
- What is parthenium?
- Why parthenium is a dangerous weed?
- What is biological control?
- How biological control works?
- Biological control by Mexican beetle
(zygogramma bicolorata) in India
- Biology of Mexican beetle
- How beetles kill the parthenium?
- Efforts of DWSR
- Collection for augmentation of the
beetles
- Can beetle harm other crops?
- How many beetles should be released?
- Biological control by competitive plants
Parthenium
hysterophorus L., commonly known as carrot weed, white top or --- congress
grass in India, 
is an herbaceous, erect
and annual plant belonging to the family Asteracae (compositae). It is most
popularly known as gajar ghas due to its appearance like carrot plant. The
origin of parthenium is considered to be from Mexico, America, Trinidad and
Argentina. After noticeable occurrence of parthenium in Pune (Maharashtra) in
1955, it has spread like a wild fire throughout India. At present parthenium
has invaded about 35 million hectares of land on In
dian. It is a nuisance on
road sides and railway tracks, vacant lands, wastelands, industrial areas, on
the sides of open drainage system and irrigation canals besides invading
agricultural crops, orchards and forest area. It mainly spreads through seeds.
A single plant can produce about 5000 – 25000 seeds. The seeds are very small
in size and light in weight.
In
general, parthenium is a poisonous, pernicious, problematic, allergic and
aggressive weed posing a serious threat to human beings and livestock. 
In India and Australia, this weed
has been considered as one of the greatest source of dermatitis, asthma,
nasal-dermal and nasal-bronchial types of diseases. Besides ill effects, it
also causes several other problems like blockage of common pathways and reduces
the aesthetic
values of
parks, gardens and residential colonies.
Biological
control is the intentional manipulation of natural enemies by man for the
purpose of controlling harmful weeds. Biological control seldom means complete
eradication of the unwanted organism, but rather maintaining its population at
lower than average that would occur in the absence of the bio-control agent.
Parthenium is mainly a weed of waste and fallow land, hence, biological control
is the most economical and practical way to keep the weed under check.
Under the
biological control programme, host specific bio agents from the native home of
the weed are imported into other countries, where the weed had entered and
became invasive. Biological control is inexpensive and poses no threat to
non-target organisms, environment and biodiversity. It is self-perpetuating and
can spreads by its own while other control measures require inputs
periodically. It is easy to integrate with other control measures.
Based on
well documented success by Mexican beetle, Zygogramma bicolorata
Pallister (Coleoptera: Chrysomelidae) in other countries where they
were introduced, beetles were imported in 1982 from Mexico to Bangalore.
Detailed host-specificity tests under quarantine conditions confirmed the
safety of Z. bicolorata to cultivated crops in the country.
Thereafter, field releases were initiated in Bangalore and India.
Beetles are off-white or light reddish in colour with dark
brown longitudinal markings on the elytra, measuring about 6 mm. in length.
Light yellow eggs are laid generally on ventral side of the leaves and hatch in
4-7 days. There are four in stars. The grubs feed for 10-15 days on the leaves
and on maturity enter into soil and pupate below up to 15 cm depth. Beetles
emerge after 8-12 days. The beetle completes its life-cycle in 27-32 days. -
Insect completes 4-5 generations from June to October in natural conditions.
The female can lay up to 2500 eggs during its lifespan. The beetle remains most
active in the field during the rainy season between June to October but stages
of Z. bicolorata may be encountered in summer and winter season depending on
the moisture and temperature.
How beetles kill the parthenium?
Both adults and larvae are
capable to feed on parthenium leaves. Larvae after hatching start to feed on
soft growing leaves, first attacking the terminal and axillary buds and later
the leaf blades, thus checking completely the plant growth and flower
production. Adults voraciously defoliate the plant. Immature flowers are cut by
the beetles in an effort to chew soft tissues beneath the flowers. Completely
defoliated plants start to show die back symptoms and gradually get killed.
Small and succulents plants are more vulnerable to larvae and beetles attack
and are nipped in the bud. In many states of India, beetle has establishment
and contributing to control several hundred hectares of land fully infested
with parthenium. At many places, beetle even controlled parthenium in the crop
fields where insets searched the parthenium amidst the crop and devoured it.
Since the first release in the
field in 1984 at Bangalore, the beetle has well established in most of the
south India and many parts of central and north India. In a very conservative
estimate, it is calculated that the beetle has already spread in about 7
million hectares of land which amounts to be about 20% area of the estimated 35
million hectares land infested with the parthenium. Initially it was feared
that beetle will not be able to survive in the extreme low and high temperature
of north and central India but it has betrayed this assumption and beetle has
established well in many parts of Haryana, Punjab, Uttar Pradesh,Uttaranchal,
Madhya Pradesh, Tamilnadu, Karnataka, Andhra Pradesh, Himanchal Pradesh and
Maharashtra.
Directorate of Weed Science
Research (DWSR) has intensified biological warfare against parthenium involving
Krishi Vigyan Kendra, NGOs, local residents and farmers. At many places in M.P.
beetles were released in the programme arranged with the collaboration of NGOs,
residential societies, clubs, municipalities etc., involving local leaders.
DWSR has also supplied nucleus cultures of the beetle to different All India
Coordinated Research Programme on Weed Control (AICRPWC) Centres in 14 states
apart from supplying to KWKs, farmers, municipalities and interested persons in
almost all the states.
DWSR also
provides consultancy on Parthenium management to private and government
agencies. DWSR released about 60 lakh beetles under consultancy programme in
different blocks and circles of Nagpur region. To obtain the beetle culture
free of cost, requests may be sent to Director DWSR in June–July.
The
beetles can easily be collected from the established sites during June to
September. Collection can be made in ordinary polythene or plastic containers
that are perforated with a needle. Upper parthenium twigs without leaves should
be placed inside the polythene to avoid the shrinking and to provide resting
place for the insect. If the insects have to be carried over long distances, it
is better to avoid leaves to prevent moisture condensation and fungal growth,
which can cause insect mortality. Care must be taken to make the initial
releases on small and succulent growth of parthenium in undisturbed areas away
from human habitations. Initial release should be avoided in cultivated land
because ploughing of land may disturb the pupation process hence poor survival
and subsequent establishment. Low lying areas prone to water logging should
also be avoided because pupation takes place in soil. The ideal time for
carrying out releases will be June to August when plenty of fresh parthenium
plants are available in nature. There is no benefit in undertaking releases
between Novembers to May when they normally do not breed. However, during this
period, beetle can be released over parthenium near the water sources
There are
no chances or harming other crops as beetle is host specific. It cannot survive
on food other than Parthenium. A controversy emerged on the feeding status
of Z. bicolorata sunflower ended in 1999, based on the report
of “Fact Finding Committee" constituted by Indian Council of Agricultural
Research.
One adult
was found to bring defoliation of a single parthenium plant in 6-8 weeks.
Therefore, if releases are to be carried out at this rate, about 0.4. to 0.7
million insects will be required per hectare, as the weed density varies
between 40 to 70 plants per square metre. In practice, it is neither possible
nor necessary to release so many insects as they are capable of multiplying
rapidly. Releases of about 500-1000 beetles can bring about establishment and
eventual control. Once plants are eaten up in the release spot the insects
migrate into adjacent areas. Taking this into consideration, a number of release
spots can be selected in a particular place or city, which can act as a focal
point.
More
releases mean quicker establishment of the beetle, Therefore, for better
control, do as many release as affordable during first couple years of introduction.
This method reduces the time in years for the beetle to build up population and
help the beetles to disperse fast. The least affordable approach is to
introduce one or two releases into infested area and do nothing more.
Cassia tora commonly
called “Chakoda" and marigold are capable to replace
Parthenium by broadcasting of seeds during February–April in the Parthenium
infested area. Plenty of seeds of C. tora may be collected
easily during October-November. Many Parthenium infested sites have been
managed by use of this technique.
Source: Directorate
of Weed Research
251 ratings
Integrated Parthenium
Management
- What is Parthenium?
- How to identify it?
- How Parthenium spreads?
- Harmful effects of Parthenium?
- Integrated management of Parthenium
- Mechanical and manual methods
- Cultural management
- Legal and extension management
- By use of chemicals
- By use of biological control agent
- Use of competitive plants
- Management by way of utilization
What is Parthenium?
Parthenium hysterophorus L.,
commonly known as carrot weed, white top or congress grass in India, is a
herbaceous, erect and annual plant belonging to the family Asteracae
(compositae). It is most popularly known as gajar ghas due to its appearance
like carrot plant. The origin of Parthenium is considered to be from Mexico,
America, Trinidad to and Argentina. After noticeable occurrence of Parthenium
in Pune (Maharashtra) in 1956, it has spread like a wild fire throughout India.
At present it has invaded about 35 million hectares of land in India. It is a
nuisance on road sides and railway tracks, vacant lands, wastelands, industrial
areas, on the sides of open drainage system and irrigation canals besides
invading agricultural crop.
How to identify it?
Parthenium leaves look like I
carrot leaves hence it is called carrot weed or gajar ghas. It may attain a
height of 1 to 1.5 meter. It is branched. Stems and leaves are covered with
fine hairs. The flowers are white.
How Parthenium spreads?
It mainly spreads through seeds.
The weed has the potential of producing as high as 154,000 seeds/m2 and
a single plant can produce about 15000 - 25,000 seeds. The seeds are very light
in weight and easily carried or transported by wind, water or through various
human activities. Parthenium has the capacity to re-grow from the cut or broken
parts. Its allelopathic effects coupled with the absence of natural enemies
like insects and diseases are two important factors responsible for its rapid
spread in India.
Harmful effects of Parthenium?
In general, parthenium is a
poisonous, pernicious, problematic, allergic and aggressive weed posing a
serious threat to human beings and livestock. In India and Australia, this weed
has been considered as one of the greatest source of dermatitis, asthma,
nasal-dermal and nasal-bronchial types of diseases. Besides ill effects, it
also causes several other problems like blockage of common pathways and reduces
the aesthetic values of parks, gardens and residential colonies.
Parthenium
also infest every type of crop, orchards, plantations and forest. It severely
reduces the crop productivity besides loss to biodiversity and environment.
Integrated management of Parthenium
Ever
since the weed became a menace in India and other countries, efforts are being
made to manage the weed by different methods. But so far, no single method has
been proved satisfactorily as each method suffers from one or more limitations
such as impracticability temporary relief, environmental safety high cost, etc.
Therefore, there is an urgent need to adopt an integrated Parthenium management
approach by amalgamating all the methods together as and when applicable.
Mechanical and manual methods
Uproot the parthenium before
flowering during monsoon when soil is wet. As sensitive persons may be allergic
to this weed, therefore, it will be better to wear gloves or use polythene bags
in hands while uprooting the Parthenium. Parthenium is not a problem of single
individual, mainly it is a problem of whole community. Therefore, there is need
to motivate colony residents, workers in industry and large farms to up root
the Parthenium in collective way.
Cultural management
Farmer
should take fast growing crop like sorghum, Jowar and daincha to suppress the
growth of Parthenium in their field.
Legal and extension management
The
management of Parthenium was also tried in India through the legal act, first
in Karnataka State. This act can be implemented at municipality or state level
to prevent the spread of Parthenium.
By use of chemicals
Parthenium in waste land can be
controlled by use of glyphosate (1 to-1.5%) for total vegetation control but if
grasses are to be saved, metribuzin (0.3 to 0.5%) or 2,4-D (2-2.5 kg a.i) can be
used. In different crops, the use of herbicides should be done only after
consulting weed scientists because for different crops, different herbicides
are required. Alaclor (2.0 kg a.i) can be used as pre-emergence to control
Parthenium in soybean, rajmaha, banana and tomato crop. Metribuzin (0.50 to
0.75 kg a.i) can be used as pre-emergence just after sowing to control
Parthenium in potato, tomato and soybean crop.
By use of biological control agent
Biological control is the
intentional manipulation of natural enemies by man for the purpose of
controlling harmful weeds. Parthenium can be managed by its natural enemies
like insects, fungi, nematodes, snails, slugs and competitive plants.
Biological control is inexpensive and poses no threat to non-target organisms,
environment and biodiversity. It is self-perpetuating and can spread on its own
while other control measures require inputs periodically. It is easy to
integrate with other control measures. Under the biological control programme,
host specific bio agents from the native home of the weed are imported into
other countries, where the weed had entered and became invasive
Based on
well documented success by Mexican beetle, Zygogramma bicolorata
Pallister (Coleoptera: Chrysomelidae), in other countries where they
were introduced, beetle was imported in 1982 from Mexico to Bangalore. Detailed
host-specificity tests under quarantine conditions confirmed the safety
of Z. bicolorata to cultivated crops in the country. This
beetle has been found effective against Parthenium. Therefore it should be
released against Parthenium.
Beetles are off white or light
reddish in colour with dark brown longitudinal markings on the elytra,
measuring about 6 mm in length. Light yellow eggs are laid generally on ventral
side of the leaves and hatch in 4-7 days. The beetle complets it’s life-cycle
in 22-32 days. Insect completes 5-6 generations under field conditions.
Both
adults and larvae are capable to feed on parthenium. By continuous feeding on
Parthenium, it gradually kill the weed. Newly emerged plants after first flush
are very vulnerable to the attack of grubs and adults.
Use of competitive plants
Parthenium
can also be managed by competitive plants like Cassia tora, Cassia
sericea Tephrosia purpurea, Achyranthes aspera etc.
But among these botanical, Cassia tora or C. sericea are widely used to replace
Parthenium. The seeds of Cassia can be collected during October- November and
should be broadcasted in April - May before monsoon on the predetermined area to
be replaced.
Management by way of utilization
Parthenium can be used for
several purposes. But it can most effectively be used in compost and vermi-compost
making. The compost should only be prepared by pit system. In NADEP method, all
the seeds of Parthenium are not killed. The Parthenium biomass should be buried
in the pit in layers. On each layer, 5 kg dung slurry and 500 gram urea should
be used. After filling the pit, it should be closed by the mixture of soil and
dung. The compost prepared by Parthenium contains more nutrients than the
compost prepared by dung only. Big plants having more fibrous stems and
branched can be used to make particle boards and composites.
Source: Directorate
of Weed Research
204 ratings
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