title: Larvicidal activity of micronized aqueous suspension of calcium hydroxide against Aedes aegypti and Culex quinquefasciatus (Diptera: Culicidae).
abstract: In the search of alternatives for the control of mosquitoes of medical importance, we evaluated the larvicidal activity of micronized suspensions of calcium hydroxide [Ca(OH)₂] against Aedes aegypti and Culex quinquefasciatus. Tests conducted under laboratory conditions determined a LC50 = 0.027% (LC90 = 0.096%) for A. aegypti and a LC50 = 0.092% (LC90 = 0.2%) for C. quinquefasciatus, at 24 h post-treatment. Considering that the LC50 for the less susceptible species killed 100% of larvae for both species at 48 h post-treatment, we decided to use the diagnostic concentration of 0.1% which eliminated 100% of larvae at 48 h under a simulated field trial. There was a residual effect for up to 84 and 70 days for A. aegypti and C. quinquefasciatus, respectively. Evaluation of Ca(OH)₂ on breeding sites showed a larvicidal activity of 100% for up to 56 days. When the micronized Ca(OH)₂ was incorporated at concentrations from 0.02% (w/v), a superficial film was formed which killed 100% of the larvae of both species after 24 h of contact, and the activity remains until the film broke apart due to stirring. The fact that Ca(OH)₂ is cheap and the people in rural areas of Mexico and other countries know the handling procedures for this compound led us to consider that 0.1% suspensions of Ca(OH)₂ could be used for mosquito control in deposits of water placed in human premises both in urban and rural areas.
authors.affiliation: Escuela Nacional de Ciencias Biológicas-IPN, 11340 México, DF, Mexico.
authors.forename: Armando
authors.initials: A
authors.lastname: Estrada-Aguilar
authors.forename: Rosa M
authors.initials: RM
authors.lastname: Sánchez-Manzano
authors.forename: José A
authors.initials: JA
authors.lastname: Martínez-Ibarra
authors.forename: Alejandro D
authors.initials: AD
authors.lastname: Camacho
authors.forename: Adrián
authors.initials: A
authors.lastname: Márquez-Navarro
authors.forename: Benjamín
authors.initials: B
authors.lastname: Nogueda-Torres
mesh_terms: D000330:Aedes / Q000187:drug effects* / Q000254:growth & development; D000818:Animals; D002126:Calcium Hydroxide / Q000494:pharmacology*; D003465:Culex / Q000187:drug effects* / Q000254:growth & development; D007306:Insecticides / Q000494:pharmacology*; D007814:Larva / Q000187:drug effects / Q000254:growth & development; D007928:Lethal Dose 50; D009032:Mosquito Control / Q000379:methods; D012996:Solutions; D014867:Water
chemical_list: D007306:Insecticides; D012996:Solutions; D014867:Water; D002126:Calcium Hydroxide