Bio Control agents for Vector control

Biocides from naturally occurring organisms.

Plant based biocides

Predatory fishes, Bugs, Mosquitoes

By-products Developed

Indigenous biocontrol agents

Bacillus thuringiensis

  • Bacillus thuringiensisOut of 218 Bacillus thuringiensis strains, one strain belonging to serotype H14 (VCRC B17) isolated from soil sample collected in Pondicherry was found to be extremely toxic to mosquito larvae.
  • The spore-toxin complex of Bti was used as the active ingredient and two formulations, a WDP (40%) and a controlled release formulation (CRF) were developed.
  • The WDP at 2.5-5 kg/ha for clear and 5-15 kg/ha for polluted habitats was found to have residual activity for about a week against Culex quinquefasciatus.
  • The CRF at 10 kg(ai)/ha was found to have a residual activity for 15 weeks in disused wells against Cx. quinquefasciatus.
  • The technology has been licensed to M/s Tuticorin Alikali Chemicals, Chennai.

Bacillus sphaericus

  • Out of 152 isolates of B. sphaericus, one isolate (Acc. No. VCRC B42) has been given 5 star ranking based on its toxicity to mosquito larvae by the WHO collaborating reference centre, Pasteur Institute, Paris, France.
  • A Water dispersible powder (40% WDP) at 10 kg(ai)/ha controls mosquito immature for a week in polluted and non-polluted water.
  • The Slow release formulation (SPHERIFIX) of this isolate at 10 kg/ha has residual activity for over 2 months.
  • The technology for the production of this agent has been assigned to NRDC for commercialization.

A bacterial metabolite showing pupicidal activity

  • B-426, a bacterial metabolite in simulated field conditions caused significant mortality of Cx. quinquefasciatus pupae and suppression of adult emergence.
  • The production technology has been assigned to NRDC.

Lagenidium giganteum

  • One indigenous isolate was found to be highly pathogenic to anophelines and culicines.
  • It caused mortality of Cx. quinquefasciatus larvae breeding in polluted cess pits and suppressed fourth instar larvae and pupal production up to a period of 40 days.

Coelomomyces indicus

  • Coelomomyces indicus This aquatic fungus was found to be naturally present in the rice fields infecting anophelines and culicines.
  • Experimental infection of An. subpictus larvae by this fungus showed that Mesocyclops leuckarti, a crustacean acts as intermediate host.

A fungal metabolite showing oviposition attractancy

  • The culture filtrate of a fungus designated as F24 was found to attract gravid Cx. quinquefasciatus females for oviposition at 10 ppm.
  • The oviposition active index was found to be +0.52.
  • The production technology has been assigned to NRDC.

Romanomermis iyengari

Romanomermis iyengari

  • A mermithid nematode has been found parasitizing aquatic stages of mosquitoes in rice fields.
  • This nematode was used to control culicines breeding in semi-polluted water, anophelines breeding in fresh waters and also tree-hole breeders like Aedes albopictus.

 

Microsporidians

  • Microsporidians (Nosema algerae and Amblyospora indicola) infected mosquito larvae are frequently found in nature.
  • The infection leads to a chronic disease causing the eventual death of the host.
  • Plasmodium failed to develop in Nosema algerae infected anopheline mosquitoes.

Parasitoids

  • The hymenopteran parasitoids viz., Pachycrepoideus vindemmiae and Dirhinus himalayanus caused 98.8% and 95.5% reduction in house flies when released at a parasitoid to host ratio of 3:10 and 10:20 respectively.
  • Tetrastichus hagenowii, an oothecal parasitoid caused 100% mortality of the host, Periplaneta americana.
Plant based Biocides

 

  • Petroleum ether extract of Croton sparsiflorus, a common weed was found to exhibit larvicidal activity at 1 mg/l.
  • Acorus calamus and Madhuca longifolia were found to produce significant inhibition in adult emergence of the three vector mosquitoes at 5 mg/l.

 

Predatory fishes, bugs, mosquitoes

Fishes

  • Aplocheilus blochii was found to be a better candidate than Gambusia affinis for the control of An. stephensi in wells
  • Ophiocephalus striatus and Macropodus cupanus were found to be effective in controlling Mansonioides mosquito breeding.
  • Among the omnivorous fishes, Ctenopharyngodon idella, Cyprinus carpio var. communis and Catla catla have been found to have a high larvivorous potential during their fry and fingerling stages.
  • Among the phytophagous fishes, Osphronemus goramy feed exclusively on aquatic vegetation and thus control mansonioid mosquito breeding.

Predatory bugs

  • Adults and nymphs of Anisops bouveri feed on mosquito larvae.
  • Diplonychus indicus and notonecta were found to be potential predators for controlling Aedes mosquitoes.

Predatory mosquitoes

Toxorhynchites splendensToxorhynchites splendens

  • Inoculative release of Toxorhynchites splendens in containers
  • Armigeres and Aedes was successfully used for controlling mosquito breeding in containers and tree-holes.

 

Evaluation of bio-control agents from industries
  • The aqueous suspension formulation of Bti (Vectobac AS) at 1.2 l/ha was effective for 2 to 8 days against Anopheles larvae whereas it was effective for 1 to 4 days against Cx. quinquefasciatus
  • The granular formulation (Vectobac G) at 7 kg/ha was effective for 2 to 9 days against Anopheles larvae and for 1 to 3 days against Cx. quinquefasciatus
  • Spicbiomoss, an aqueous suspension formulation of B. sphaericus at 120 l/ha was not effective against the immature of anophelines and was effective against Cx. quinquefasciatus for 6-13 days in cement tanks, 3-8 days in cesspits, 2-9 days in drains.

 

By-products Identified

Production of Cyclosporin A, an immunosuppressive agent

  • In the search for microbial agents for mosquitocidal properties, a fungus, Tolypocladium sp. producing cyclosporin was isolated.
  • A pilot scale process for the production of cyclosporin A and a HPLC method for the identification of cyclosporin A, B and C in fermentation samples were developed and the same was transferred to M/s Nixcil Pharmaceuticals & Specialities Ltd., Lucknow.

Production of Thrombinase, a thrombolytic enzyme


 

  • A protease enzyme with fibrinolytic Thrombolytic enzymeactivity was identified while searching for the by-products of biocides.






  • A pilot scale production process for thrombinase from the culture broth of B. sphaericus was developed and the same has been transferred to Maladi Research Centre, Chennai.
Last Updated on : 07/04/2014