title: Aedes aegypti (Diptera: Culicidae): evaluation of natural long-lasting materials containing pyriproxyfen to improve control strategies.
abstract: Natural materials such as beeswax or a paraffin/stearin mixture containing pyriproxyfen and used as a slow release formulation may convert any breeding place into a larvicidal ovitrap for Aedes aegypti (L.) control. Effectiveness and residual activity of beeswax and paraffin/stearin 1:1 discs containing from 10(-5) to 10(-1) % pyriproxyfen and sticked at the bottom of plastic jars were evaluated for adult emergence inhibition (EI) on late 3rd or early 4th instar A. aegypti larvae. At the initial time t = 0, the EI was 100% for vessels containing beeswax or paraffin/stearin 1:1 discs containing up to 10(-4)% pyriproxyfen. For the lowest pyriproxyfen concentration of 10(-5)%, paraffin/stearin mixture gave a higher EI% value than beeswax (100 and 50%, respectively). Jars were kept at room temperature, and water was totally replaced every 15 days. Bioassays for residual activity repeated monthly showed that at 30 days and for pyriproxyfen 10(-5) % and both matrices, the EI values were low and comparable to control values. For pyriproxyfen 10(-4) %, EI remained above 95% for at least 90 days and around 75% up to 180 days. The EI values are always higher for paraffin/stearin mixture than for beeswax. For all other higher concentrations, 100% EI was obtained at least during 300 days. In a semi-field trial, paraffin/stearin/sand O-rings (2:1:2), containing pyriproxyfen 1%, were sunken in 200-l water-storage tanks and held outdoors in a shadow place. After 72 h, a 250-ml aliquot was taken (t = 0) obtaining 100 % EI. Water level was completed to 200 l every 15 days and bioassays repeated monthly as before. Residual activity remains with 100% EI at least for 6 months.
authors: Centro de Investigaciones de Plagas e Insecticidas (CIPEIN-CITEDEF-UNIDEF (MINDEF/CONICET), Juan Bautista de La Salle 4397, B1603ALO, Villa Martelli, Buenos Aires, Argentina.
authors: Emilia
authors: E
authors: Seccacini
authors: Laura
authors: L
authors: Juan
authors: Eduardo
authors: E
authors: Zerba
authors: Susana
authors: S
authors: Licastro
mesh_terms: D000330:Aedes / Q000187:drug effects*; D000818:Animals; D007605:Juvenile Hormones / Q000737:chemistry / Q000494:pharmacology*; D007814:Larva / Q000187:drug effects; D009032:Mosquito Control / Q000379:methods; D010058:Oviposition; D010232:Paraffin / Q000737:chemistry*; D011725:Pyridines / Q000737:chemistry / Q000494:pharmacology*; D014885:Waxes / Q000737:chemistry*
chemical_list: D007605:Juvenile Hormones; D011725:Pyridines; D014885:Waxes; C038228:beeswax; C055613:pyriproxyfen; D010232:Paraffin