Chemical agents for mosquito control

Due to development of resistance in vectors to conventional insecticides and undue persistence of certain insecticides in environment, research is warranted for the development of new chemical agents for vector control. The Centre has evaluated many indigenous compounds and insecticides from pesticide industries for developing products for controlling mosquito vectors as per the World Health Organization Pesticide Evaluation Scheme (WHOPES).

indigenous Products
Evaluation of insecticides from Pesticide Industries
 

Indigenous Products

 

Development of an insect repellent DEPA (N,N-DIETHYL PHENYL ACETAMIDE)

  • Out of 120 substituted amides synthesized, six compounds offered more than 6 hr protection against Ae. aegypti and among them, DEPA was more effective.

  •     The repellent has been formulated as vanishing cream, a polymer based liquid and a microsphere lotion.

  •     The technology was transferred to Defence Research and Development Establishment, Gwalior for commercial exploitation.


Development of synthetic pyrethroid esters

 

  •     Out of thirty-nine pyrethroid esters synthesised two, a-Cyano-3-phenoxybenzyl-2(4-fluorophenoxy)-3-methyl butanoate and a-Cyano-3-phenoxybenzyl-2 (4-chlorophenoxy)-3-mehyl butanoate were found to exhibit larvicidal and adulticidal activities against Cx. quinquefasciatus.

Development of insect growth regulators

  •     Among 30 substituted diphenyl ethers and 120 diphenylureas synthesised and tested, three compounds DPE-16, 19 & DPE-28 were found to be effective against Cx. quinquefasciatus.

  •     The technology for the development of controlled release formulation of DPE-28 has been assigned to NRDC.

  • Environment-friendly controlled release formulations of mosquito larvicides

  •     Incorporation of gelatin, an interactive polymer with NaCMC increased the stability of fenthion, temephos and diflubenzuron for 55 weeks enabling single application for one year. Equipment for application is not required.

Development of an oviposition attractant

  •     Among 108 esters synthesized, Ethyl crotonate (E-57) was found to exhibit significant oviposition attractancy even in the presence of a pheromone extracted from the apical droplets of egg rafts of Cx. quinquefasciatus.

 

Evaluation of insecticides from Pesticide Industries

Organophosphorus compounds

  •     Zolone was found to be effective as an adulticide against An. culicifacies in the laboratory.

  •     Reldan and Dursban were found to be highly effective against larvae and adults of An. fluviatilis and An. culicifacies.

  •     Reldan at 500 g(ai)/ha was effective for a mean duration of 4, 4.5 and 3.6 days in cesspits, cement tanks and U-drains against Cx. quinquefasciatus.

  •     Dursban at 500 g(ai)/ha this application rate was effective for 4.6 and 3.7 days in cesspits and cement tanks and not effective in drains.

  •     Dursban was effective at 1000 g(ai)/ha for 4 days in drains.

  •     Pirimiphos-methyl and phendal were effective against larvae and adults of Cx. quinquefasciatus, Ae. aegypti, An. stephensi and An. culicifacies in the laboratory.

Carbamate compounds

  •     Bendiocarb in the laboratory evaluation was found to be an effective adulticide and larvicide against Cx. quinquefasciatus, Ae. aegypti, An. stephensi and An. culicifacies.

  •     Bendiocarb (Ficam W) when sprayed in houses made up of mud, cement and thatch at the rate of 400 mg(ai)/m2 was found to be effective for six weeks in keeping the mosquito abundance of Cx. quinquefasciatus and An. subpictus low.

  •     The granular formulation of fenoxycarb (OMS 3010) was more effective than EC and ME by preventing adult emergence of Cx. quinquefasciatus in cement tanks and cesspits.

Synthetic pyrethroids

  •     Permethrin was found to be an effective adulticide and larvicide in laboratory evaluation against Cx. quinquefasciatus, Ae. aegypti, An. culicifacies and An. culicifacies.

  •     Permethrin impregnated bednets at 0.5 g(ai)/m2 was found to reduce the indoor resting density of An. culicifacies for three months.

  •     K-Othrine (Deltamethrin) was found to be effective as an larvicide and adulticide in laboratory evaluation against vector species.

  •     The residual effect of K-Othrine on different surfaces under simulated condition lasted for 17 weeks at 100 mg(ai)/m2.

  •     Indoor residual treatment with deltamethrin at 25 mg(ai)/m2 was found to keep the indoor resting density of Mansonia annulifera low for six weeks.

  •     Cyfluthrin (OMS 2012) at 20 and 50 mg(ai)/m2 was found to keep the indoor resting density of Cx. quinquefasciatus low for 14 and 18 weeks respectively.

  •     Fenfluthrin (OMS 2013) at 20 mg(ai)/m2 was found to reduce the indoor resting density of An. subpictus for five weeks following spraying.

  •     Alphacypermethrin (OMS 3004 - Fendona) at dosages 0.01 to 0.1 mg/l gave control for one to four weeks against Cx. quinquefasciatus in different habitats.

  •     When Fendona was sprayed at 100 mg(ai)/m2, the density of Cx. quinquefasciatus and An. subpictus was kept low for 18 - 27 weeks.

  •     Tralomethrin (OMS 3048), a pro-pesticide at 50 mg(ai)/m2 showed a residual effect for 15 weeks against vector mosquitoes.

  •     Tralomethrin was effective in suppressing the immature of Cx. quinquefasciatus for 1-2 days in cesspits and drains and for 10-24 days in cement tanks at 0.2 mg/l.

  •     Lambdacyhalothrin impregnated bed-nets reduced the malarial parasite rate in all the age groups for six months after the use of impregnated nets.

Insect growth regulators

  •     Methoprene successfully inhibited adult emergence of Cx. quinquefasciatus at a target dose of 2 mg/l.

  •     OMS 3009, OMS 2015 & OMS 3013 were effective against Cx. quinquefasciatus for one week in cesspits at 1.0 mg/l.

  •     OMS 3009 and OMS 3013 were effective for 3 and 6 weeks in cement tanks at the respective doses of 0.5 and 0.05 mg/l.

  •     S-21149 and S-31183 produced more than 80% emergence inhibition against Cx. quinquefasciatus in cesspits for 2-19 days at the dosages ranging from 0.05 to 0.5 mg/l and in cement tanks for 7-45 days at the dosages ranging from 0.005 to 0.5 mg/l.

  •     Hexaflumuron (OMS 3031 - XRD 473) was found to be more effective against Cx. quinquefasciatus than the other species in suppressing the adult emergence.

  •     The effect on non-target organisms like predatory fishes, insects, cyclopoid copepod and nematode parasite, R. iyengari clearly showed that this IGR is safe and selective for mosquito control.

  •     Insecticidal activity of an organosilane (HOE 84498-OMS 3055), organophosphorus (MAT 9460-OMS 3052) and a synthetic pyrethroid, ether, Trebon (OMS 3002) was limited to larval stages only.


Surface film-producing compounds

  •     Monox CI-FCM successfully inhibited the adult emergence of Cx. quinquefasciatus at a target dose of 1.89 litres of 1% solution per square meter.

  •     Arosurf MSF-ISA 20E) significantly alters the surface tension of water in all types of breeding habitats and causes mortality in larvae and pupae and inhibits adult emergence of Cx. quinquefasciatus for upto twelve weeks at a dosage of 11.2 l/ha.

Insecticide impregnated fabric trap (IIFT)

  •     IIFT has been developed to sample mosquitoes for monitoring vector density and transmission parameters and the samples from this trap were quantitatively comparable with the hand catch.

Insecticidal paint

 

  •     The insecticidal paint formulation, Vernacide tested for its adulticidal efficacy was highly effective in producing 100% mortality against Cx. quinquefasciatus and Periplaneta americana for eight months.

Last Updated on : 07/04/2014