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Bio-control and Bio-pesticides in IPM
Introduction
Natural
ecosystems
have
abundance of natural enemies
of pests. Natural enemies keep
pest
populations
in
check,
where man does not interfere.
Greatest harm to these farmers’
friends
is
caused
by
indiscriminate use of pesticides.
Pest
management
thus
lays
emphasis on conservation of
natural
enemies
enemies.
are
also
Natural
compatible
with resistant varieties.
Conserve non- target organisms
In fact, biological control along
with cultural methods should
form the
core
of any
IPM
programme. Natural enemies
insect
DB-Mechanical
Methods
Disease
DB-Cultural
methods
DB-Physical
methods
are a gift of nature to farmer
and they need to be conserved
ETL
DB-Bio-control
methods
IPM
DB-Chemical
methods
for taking their advantage.
An IPM programme should be
basically based on conservation
of
native
natural
enemies,
cultural methods and resistant
cultivars
and
other
management tactics should be
incorporated
based
availability and need.
on
Multipest-modules
nematode
weeds
Dissemination
Multiple pest management programmes
IPM Concept
Biological Control
Biological control refers to use of
natural
enemies
of
pests
such
as
parasitoids, predators and pathogens
to suppress pest populations. Crop
ecosystems are replete with natural
enemies
but
these
need
to
be
conserved against harmful effect of
pesticides.
Likewise,
bio-pesticides
like
plant
extracts or pathogens are also used to
contain
pests.
Trichogramma
Parasitoids
such
as
are
used
to
suppress borer pests.
also
Spider- Prolific predator
Predators
Spiders, predatory bugs, predatory
beetles such as lady bird beetles,
rove beetles and ground beetles,
syrphids, predatory crickets and
grasshoppers take heavy toll of crop
pests. Vertebrate predators such as
birds, fish and ducks also feed on
Ground beetle
crop pests.
Spiders: Spiders are dominant and
most common predators in rice
ecosystem. Spiders consume 5-15
insects a day depending upon their
size.
Moths
and
flies
are
ensnared and eaten by spiders.
also
Spider with egg case
Lady bird beetles
Lady beetles are very important
predators
of
aphids
and
other
sucking pests and can be seen in
large number especially on rabi
crops
like
coriander
mustard,
etc.
Both
wheat,
grubs
and
Adult of lady bird beetle
adults feed voraciously on pests.
While
spraying
pesticides,
care
should be taken to spare these
useful predators through selective
application.
Syrphids
Maggots of hoverflies also feed on
Grub of lady bird beetle
aphids.
Rove beetles
Rove beetles feed on larvae of leaf
folder and hairy caterpillar, and
planthoppers.
Ground beetles feed on larvae of leaf
folder,
and
planthoppers.
Each
predator can consume 3-5 larvae per
Rove beetle
day.
Lace wings
Lace wing grubs also feed on aphids
and thus help in reducing crop
losses due to pests.
Grub of lace wing
Predatory
crickets
and
grasshoppers
Sword-tailed
predators
and
crickets
consume
are
eggs
egg
of
several rice pests. Likewise meadow
grasshoppers feed on eggs of rice
bug and stem borer, and nymphs of
Predatory cricket
planthoppers.
Dragon and Damsel flies
Dragon and damsel fly adults also
feed on flying insects, thereby aiding
in their biological control. They are
found in abundance near water
bodies.
Dragon fly
Vertebrate
Predators
predators
like
sparrows,
mynahs, ducks, frogs and fish
are also reared in rice fields and
they
heavily
consume
planthoppers and other pests,
besides providing extra income
to farmers. Birds also follow the
plough or tractor and pick up
Crows feeding soil pests
exposed soil pests.
Sparrow
Parasitoids
Parasitoids are tiny insects which feed on
eggs,
larvae
or
pupae
of
pests.
Eggs
parasitoids of stem borer and leaf folder
such
as
Trichogramma,
Telenomus
and
Tetrastchus; egg parasitoids of leaf and
planthoppers like Gonatocerus and Anagrus,
and larval parasitoids
such as Apanteles,
Bracon, Stenobracon play very important
role in pest suppression under natural field
conditions.
Stenobracon parasitoid
Inundative releases (Table 1) of
insectary
reared
egg
parasitoid
Trichogramma (Trichocard) are also
undertaken to contain stem borers
in rice, maize and sugarcane, cotton
bollworms,
rice
leaf
folder.
Trichocards
Trichogramma spp. are released @ 11.5
lakh/ha/week
number
weeks
for
variable
depending
upon
need.
These releases act like application
of
insecticides
achieved
through
individuals only
their progeny.
and
control
is
released
and not through
Braconid wasp
Table 1 Inundative releases of natural enemies against pests
Pest
Natural enemy
Release/application
Rice yellow
stem borer &
leaffolder
Trichogramma
japonicum & T.
chilonis
Inundative release @50,000100000/ha/week for 5 weeks
Sugarcane
pyrilla
Epiricania
melanoleuca
Periodic release @800010,000 cocoons or 800,0001000,000 eggs/ha
Maize stem
borer
T. chilonis
Inundative releases @
100,000/ha/3 days - 5 times
Tobacco
caterpillar
Telenomus remus
(egg parasitoid)
3 fortnightly releases @
40,000/ha
Cotton
bollworms
T. chilonis,
@ 1,50,000/ha/7-10 days
during egg laying period
@ 2 larvae/plant during peak
egg hatching
Chrysopa carnea
Pathogens
Entomopathogenic
Beauveria,
fungi
like
Metarhizium,
Entomophthora also play important
role in suppressing populations of
planthoppers
and
other
pests.
Likewise, entomogenous nematode,
NPV infected insect larva
Courtesy: http://butterflybreeders.com
Steinernema carpcapsae also help to
control
crop
pests.
Nucleopolyhedrosis virus (NPV) have
been found to be effective against
tobacco caterpillar (Spodoptera) and
gram pod borer (Helivoverpa).
NPV infected larva haging upside down
Biopesticides
Bacteria, Bacillus thuringiensis
(Bt)
is
effective
against
lepidopteran pests.
Neem products like neem seed
kernel extract (NSKE) is effective
against suckng pests and other
foliage feeders.
Conservation of natural enemies
Ensure need based application of
pesticides
Avoid use of broad spectrum
pesticides
Don’t treat area having natural
enemy abundance.
Conserve spiders
Let’s Sum up
Biological control refers to use of natural enemies of pests to suppress pest
populations.
Predators like spiders, predatory bugs, lace wings, predatory beetles,
predatory crickets, grasshoppers and birds take heavy toll of crop pests.
Parasitoids are tiny insects which feed on eggs, larvae or pupae of pests.
Trichogramma is an important egg parasitoid of stem borers, bollworms and
leaf folders.
Inundative releases of insectary reared Trichogramma (Trichocard) are
also undertaken to contain stem borers, cotton bollworms and leaf folders.
Fungi like Beauveria, Metarhizium, Entomophthora play important role in
suppressing populations of planthoppers and other pests.
Nematode, Steinernema carpcapsae and nucleopolyhedrosis virus (NPV)
have also been found to be effective against pests like tobacco caterpillar and
gram pod borer.
 Biopesticides such as Bacillus thuringiensis (Bt) and neem seed kernel
extract (NSKE) are effective against rice pests.
Conservation of natural enemies can be ensured through need-based
application of selective pesticides.