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

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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. Natural enemies
are also compatible with resistant varieties.
Conserve non- target organisms
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In fact, biological control along with cultural
methods should form the core of any IPM
programme. Natural enemies are a gift of nature
to farmer and they need to be conserved 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 on availability and need.
IPM Concept
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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.
  Parasitoids such as Trichogramma are also used to
  suppress borer pests.

Spider- Prolific predator
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• 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 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 also ensnared and eaten by
  spiders.

Ground beetle
Spider with egg case
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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 mustard, wheat, coriander etc. Both
grubs and 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 aphids.
Adult of lady bird beetle
Grub of lady bird beetle
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• 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 day.
• Lace wings
• Lace wing grubs also feed on aphids and thus help
  in reducing crop losses due to pests.

Rove beetle
Grub of lace wing
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Predatory crickets and grasshoppers Sword-tailed
crickets are egg predators and consume eggs of
several rice pests. Likewise meadow grasshoppers
feed on eggs of rice bug and stem borer, and
nymphs of 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.
Predatory cricket
Dragon fly
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• 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 exposed soil pests.

Crows feeding soil pests
Sparrow
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• 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
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• 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. Trichogramma spp. are released _at_ 1-1.5
  lakh/ha/week for variable number weeks depending
  upon need.
• These releases act like application of
  insecticides and control is achieved through
  released individuals only and not through their
  progeny.

Trichocards
Braconid wasp
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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 _at_50,000- 100000/ha/week for 5 weeks
Sugarcane pyrilla Epiricania melanoleuca Periodic release _at_8000-10,000 cocoons or 800,000-1000,000 eggs/ha
Maize stem borer T. chilonis Inundative releases _at_ 100,000/ha/3 days - 5 times
Tobacco caterpillar Telenomus remus (egg parasitoid) 3 fortnightly releases _at_ 40,000/ha
Cotton bollworms T. chilonis, Chrysopa carnea _at_ 1,50,000/ha/7-10 days during egg laying period _at_ 2 larvae/plant during peak egg hatching
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• Pathogens
• Entomopathogenic fungi like Beauveria,
  Metarhizium, Entomophthora also play important
  role in suppressing populations of planthoppers
  and other pests. Likewise, entomogenous nematode,
  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 insect larva Courtesy
http//butterflybreeders.com
NPV infected larva haging upside down
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• 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
• Dont treat area having natural enemy abundance.

Conserve spiders
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• Lets 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.