Potential Use of Pyriproxyfen for Control of Aedes aegypti (Diptera: Culicidae) in Iquitos, Perú

• Published in: Journal of medical entomology 2005-07, Vol.42 (4), p.620-630
• Main Authors: Sihuincha, Moisés, Zamora-perea, Elvira, Orellana-rios, Wagner, Stancil, Jeffrey D., López-sifuentes, Victor, Vidal-oré, Carlos, Devine, Gregor J.
• Format: Article
• Language: English
• Subjects: Aedes - growth & development; Aedes aegypti; Animals; Biological and medical sciences; eclosion; egg hatchability; fecundity; Fundamental and applied biological sciences. Psychology; horizontal insecticide transfer; horizontal transfer; Insect Repellents; Insecta; insecticide residues; Insecticides; Invertebrates; Juvenile Hormones; larvicides; lethal dose 50; Medically important nuisances and vectors, pests of stored products and materials: population survey and control; mortality; mosquito control; Mosquito Control - methods; oviposition sites; Peru; pesticide persistence; Pyridines; pyriproxyfen; toxicity; VECTOR CONTROL, PEST MANAGEMENT, RESISTANCE, REPELLENTS; Vectors. Intermediate hosts; water storage tanks
• ISSN: 0022-2585; 1938-2928
• DOI: 10.1603/0022-2585%282005%29042%5B0620%3APUOPFC%5D2.0.CO%3B2

The effects of pyriproxyfen were tested against a local population of Aedes aegypti (L.) in Iquitos, Perú. Bioassays showed that, when applied to late instars, pyriproxyfen prevented adult emergence at extremely low concentrations (LC50 = 0.012 ppb). There was no adult emergence from water sampled from storage tanks that had been seeded with the equivalent of 50–83 ppb (AI) pyriproxyfen. Five months after treatment, despite constant dilution of these tanks, water sampled from these sources continued to be lethal to larvae and pupae. Additional studies, carried out in the laboratory, showed that groups of five or 20 female blood-fed mosquitoes, exposed to residues of ≈0.003 g (AI) pyriproxyfen/m2, could transfer enough chemical to new oviposition sites to prevent ≈80% of adult emergence from larvae developing in that previously uncontaminated water. Moreover, although the fecundity of the adult females used as the transfer vehicles in these tests was unaffected, the subsequent eclosion of the eggs that these mosquitoes laid was decreased by 70–90%. It also was shown that, at very high concentrations (>30,000 ppb), pyriproxyfen-treated water sources were as likely to be used as oviposition sites as untreated sources. These data suggest that treated sites might act as sinks for mosquito reproduction and moreover that such sites might act as dissemination sources for the horizontal transfer of larvicides to new environments by mature females. We review the literature on the environmental and human health effects of this compound and discuss its potential for use as a mosquito control agent in the field.