Field trial of Novaluron, an insect growth regulator larvicide against larvae of polluted-water mosquitoes in Thailand
Apiwat Tawatsin 1*
Preecha Asavadachanukorn 2
Usavadee Thavara 1
Mir S. Mulla 3

Affilications :
      1 National Institute of Health, Department of Medical Sciences, Ministry of Public Health, Nonthaburi 11000, Thailand
       2 Department of Statistics, Faculty of Commerce and Accountancy, Chulalongkorn University, Bangkok 10330, Thailand
       3 Department of Entomology, University of California, Riverside, California 92521, USA
      *Contact e-mail: apiwat@dmsc.moph.go.th

Source:
      Presented in the 15th European congress of the Society for Vector Ecology, Serres, Greece, 10-14 April 2006.

Language :
      English

Abstract :
       Novaluron, an insect growth regulator belonging to the benzoylphenyl urea insecticide, was evaluated in the field against larvae of polluted-water mosquitoes, mostly Culex quinquefasciatus. The study was carried out in highly polluted developmental sites infested with heavy populations of mosquito larvae in low-income communities in urban areas of Bangkok, Thailand. An EC10 (emulsifiable concentrate containing 10% active ingredient) formulation of the larvicide was premixed in water and applied by pressurized spray tank at the rate of 0.1 ml of the EC10/m2 (equal to 10 mg AI/m2) of the breeding sites. Assessments were made by sampling mosquito larvae and pupae to determine the trends of immature populations before treatment and then 3 days and weekly after treatment. Reduction of the populations in percent was then computed by comparing counts of larvae and pupae to the pretreatment counts of the same stages at each particular site. It was found that the immature populations of mosquitoes in the treated areas were dramatically suppressed and remained at extremely low levels for 3 to 7 weeks after each treatment depending on the prevailing conditions of each experimental site. No negative impact on fishes or aquatic plants in the treated areas was detected during and after the experiment. It is thus evident that novaluron is effective to control immature populations of polluted-water mosquitoes, especially Culex quinquefasciatus in urban areas.

Key Words: Novaluron, IGR, larvicide, mosquito control, Culex quinquefasciatus