Efficacy of novaluron against Culex quinquefasciatus in small- and medium-scale trials, India.

Novaluron 10% emulsifiable concentrate (EC), an insect growth regulator (IGR), was tested against Culex quinquefasciatus immatures at 1, 5, and 10 mg active ingredient (AI)/m2 applied to cesspits, drains, and abandoned wells. The IGR produced 80-100% inhibition of adult emergence (IE) for > 1 week (10-14 days) in cesspits, 1-2 weeks in street drains, and 5-10 weeks in abandoned wells at the 3 application rates. The efficacy increased with the increasing dose in street drains and abandoned wells. The residual activity of the IGR was longer in abandoned wells compared to drains and cesspits. Based on the small-scale trial, doses of 1, 5, and 10 mg AI/m2 were used in the medium-scale trial for cesspits, abandoned wells, and street drains, respectively. The efficacy observed in medium-scale trial was similar to that in the small-scale trial. The results indicate that novaluron 10% EC can be used for larval control against Cx. quinquefisciatus at the application rate of 1 mg AI/m2 at 10-day intervals in cesspits, at 5 mg AI/m2 at 2-month intervals in abandoned wells, and at 10 mg AI/m2 applied at fortnightly intervals to drains. Even at the lowest rate of 1 mg AI/m2, the IGR prevented adult emergence for at least a week in cesspits and street drains and for a month in abandoned wells. Novaluron 10% EC could be one of the options for larval control operations in integrated vector management.