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Biological control

  2.  Term biological pest control first used by Harry Scott Smith at the 1919 meeting of the American association of economic entomologists at California  The first report of the use of an insect sp.To control an insect pest comes from Nan Fang Cao Mu Zhuang (Plants of the southern region) by Ji han (Botanist).
  3.  Biological control started to emerge in 1870 in U.S.A.  First international shipment of an insect as an biological control agent was made by CharlesV Riley in 1873. Shipping to France the predatory mites to help fight grape vine disease agent Phylloxera  The first importation of the parasitoid into U.S. was of Cotesia glomerata imported from Europe to control cabbage white butterfly.
  4.  Relies on predation, parasitism and other natural mechanisms. There are three basic strategies : 1. IMPORTATION 2. AUGMENTATION 3. CONSERVATION
  5. Importation: classical biological control involves the introduction of pests natural enemy to a new location where they do not occur naturally . o One of the earliest success in west was in controlling Icerya purchasi(cottony cushion scale) in Australia using a predatory insect Rodolia cardinalis (vadalia beetle). o Parasitoidal waspsTrichogramma ostriniae to control European corn borer Ostrinia nubilalis.
  6. Augmentation: Involves the supplemental release of natural enemies , boosting the naturally occurring population . o All activities designed to increase numbers or effect of existing natural enemies, achieved by releasing additional numbers of a natural enemy into a system or modifying the environment in such a way as to promote greater number or effectiveness.
  7.  PERIODIC RELEASES OF AUGMENTATION • Inoculative release: small numbers of the control agents are released at intervals to allow them to reproduce in the hope of setting up longer term control and thus keeping the pest down to a low level ; constituting prevention rather than cure. • Examples : inoculative release in green house production of several crops ;periodic releases of the parasitoid Encarsia formosa are used to control green house white fly while predatory mites Phytosieulus persimilis used for control of spotted spider mite . • Inundative release: involves mass culture and release of natural enemies to suppress the pest population directly . • Example : massive release of Trichogramma sp. in vegetable or field crops and release rates ranges from 5000- 200000 per acre per week according to level of pest infestation .
  8.  Conservation: Involves avoidance of measures that destroy natural enemies and the use of measure that increase their longevity and reproduction of the natural enemies in an environment . o Natural enemies are already adapted to the habitat and to the target pest and their conservation can be simple and cost effective . Conservation involves :  Avoidance of harmful cultural practices.  Maintenance of diversity  Habitat manipulation practice ,providing suitable habitat such as shelters , natural food , artificial food supplements to increase the population of natural enemies.  Protection from pesticides.
  9.  PREDATORS  PARASITOIDS  PATHOGENIC MICROORGANISMS • Bacteria • Fungi • Nematodes • Protozoa • Viruses
  10.  PREDATORS: are mainly free living species that directly consume a large number of prey during their whole life time . Example: Lady bugs particularly their larvae which are active between May and July are predators of Aphids and also consume mites, sacle insects. Spotted lady beetle Coleomegilla maculata feed on eggs and larvae of the colorado potato beetle Leptinotarsa decimlineata
  11.  Parasitiods: lay their eggs on or in the body of an insect host which is then used as a food for developing larvae.The host is ultimately killed , most insect parasitoids areWasps .  Important groups are: • Ichneumonid wasps :which prey mainly on caterpillars of butterflies. • Brachonid wasps: which attack caterpillar and wide range of other insects including green fly. • Chalcid wasps: which parasitises eggs and larvae of green fly , white fly , cabbage caterpillars and scale insects. • Tachanid fly: which parasitise a wide range of insects including caterpillars, adult, larval beetles and true bugs.
  12.  Bacteria : used for biological control infects insects via their digestive tract so they offer only limited options for controlling insects with sucking mouth parts such as aphids and scale insects . • Examples : Bacillus thuringiensis is most widely applied species of bacteria used for biological control and it can be used against Lepidoptera , Coleoptera, Diptera. • Bacillus Popilliae causes Milky spore of the white grubs of Japanese beetle . • Bacillus sphaericus used against Diptera .
  13.  Gram positive TARGET INSECTS FOR BtTOXIN  Aerobic  Sporogenous  Rod shaped  Entomopathogenic Lepidoptera Diptera Coleoptera Hymenoptera Nematodes
  14. SPORE CRYSTALS ‘CRYSTAL’ Crystals made up of 1 or more Cry proteins Bacillus thuringiensis spore and cry protein(toxin)
  15. solubilization In gut lumen, activation of protoxin to 3-d toxin to the cadherin receptor Common to both models Pore forming Cleavage of α- helix Oligomerized toxin binds to glycosylphosphatidylinositol (GPI) anchored receptors Activation of Mg2+-dependent signal transduction pathway leading to cell death (oncosis) Stimulation of heterotrimeric G protein and adenyl cyclase Increase in levels of cAMP cAMP activates protein kinase A Cellular alteration like cytoskeletal rearrangement and ion fluxing Alteration in cell chemistry and cell death Signal transduction
  16.  Fungi : used successfully to protect crops from a variety of pests. • They can infect a wide range of insect hosts. • There has been only limited success in Fungi as biological control agent because Fungi are slow to kill their host.Whereas some Fungi have a broad host range . • Examples: Beauveria bassiana is mass produced and used to manage a wide variety of insect pests including:White flies,Thripes,Aphids, Weevils. • Metarhizium anisopliae produce toxin destruxins used against Beetls , Locusts, and grasshoppers. • Trichoderma viride used against silver leaf disease of stone fruits caused by Chondrostereum perpureium . • Verticillium lecanii used for control of aphids and white flies. • Lagenidium giganteum aquatic fungi used against mosquito larvae. • Aschersonia aleyrodis used against scale insects and white flies. • Cordyceps sp. Against arthropods.
  17.  Nematodes: Resides in soil , soft bodied , non segmented, obligate or facultative parasite on broad range of insects. Introduces new and environmental- friendly way to eliminate plant pest. • These harbors gut bacteria which helps in pathogenesis ; symbiotic association with bacteria. • Examples:NEMATODES BACTERIA Steinernema carpocapsae Xenorhabdus nemadophilus Steinernema affinis Xenorhabdus bovienii Steinernema glaseri Xenorhabdus pionarii Heterorhabdus bacteriophora Photorhabdus leuminiscense Heterorhabdus megidis Photorhabdus leuminiscense Heterorhabdus zealandica Photorhabdus leuminiscense
  18.  When Heterorhabdus attacks insect larva it turns red.  When Steinernema attacks insect larva it turns brown .
  19. Examples:
  20.  Viruses:are obligate disease causing organisms that can reproduce within a host insect. • They can provide safe , effective and sustainable control of a variety insect pests usually attack larvae of lepidoptera or hymenoptera. • Viruses are host specific .Virus induced mortality is caused by toxic proteins that accumulate during reproductive cycle of virus after death of insect the integument and internal tissues melt away.
  21. • Bculoviruses are arthropod specific group : • Two genera : I. Nuclear polyhedrovirus(multiple virions occluded in polyhedra). After Infection larvae initially white then darken. I. Granulovirus(single virion occluded in granules). After infection larvae turns milky white and stop feeding. Examples: Lymantria dispar used against larvae of Gypsi moth . U.S. forest service has used NPVs as biological control agents for Pine saw flies,Tussock moths.
  22. • Baculovirus is sprayed onto foliage –> Caterpillar consumes the virus –>The protein encapsulating the Baculovirus DNA dissolves and the DNA enters the stomach cells – > Baculovirus DNA is replicated by the stomach cells until the stomach cells rupture –>The caterpillar stops eating –> Baculovirus is spread throughout the caterpillar causing a general systemic infection –>The caterpillar dies within day
  23.  Upadhyay,R.K., Mukherji,K.G., and Rajak,R.L. IPM system in agriculture.  De Bach, P. Biological control of insect pests and weeds, Chapan and Hall, New yYork.  Burges,H.D. and Hussey,N.W. Microbial control of insect and mites.  Saxena, A. B. Biological control of insect pest.  Wikipedia.

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