Aedes aegypti (Diptera: Culicidae): evaluation of natural long-lasting materials containing pyriproxyfen to improve control strategies

EMILIA SECCACINI ; LAURA JUAN ; EDUARDO ZERBA ; SUSANA LICASTRO

PARASITOLOGY RESEARCH

SPRINGER

Lugar: Berlin; Año: 2014 vol. 113 p. 3355 - 3360

0932-0113

Abstract Natural materials such as beeswax or a paraffin/stearin mixture containing pyriproxyfen and used as a slowrelease formulation may convert any breeding place into alarvicidal ovitrap for Aedes aegypti (L.) control. Effectivenessand residual activity of beeswax and paraffin/stearin 1:1 discscontaining from 10−5 to 10−1 % pyriproxyfen and sticked atthe bottom of plastic jars were evaluated for adult emergenceinhibition (EI) on late 3rd or early 4th instar A. aegypti larvae.At the initial time t=0, the EI was 100 % for vessels containingbeeswax or paraffin/stearin 1:1 discs containing up to10−4 % pyriproxyfen. For the lowest pyriproxyfen concentrationof 10−5 %, paraffin/stearin mixture gave a higher EI%value than beeswax (100 and 50 %, respectively). Jars werekept at room temperature, and water was totally replacedevery 15 days. Bioassays for residual activity repeated monthlyshowed that at 30 days and for pyriproxyfen 10−5 % andboth matrices, the EI values were low and comparable tocontrol values. For pyriproxyfen 10−4 %, EI remained above95%for at least 90 days and around 75%up to 180 days. TheEI values are always higher for paraffin/stearin mixture thanfor beeswax. For all other higher concentrations, 100 % EIwas obtained at least during 300 days. In a semi-field trial,paraffin/stearin/sand O-rings (2:1:2), containing pyriproxyfen1 %, were sunken in 200-l water-storage tanks and heldoutdoors in a shadow place. After 72 h, a 250-ml aliquotwas taken (t=0) obtaining 100 % EI. Water level wascompleted to 200 l every 15 days and bioassays repeatedmonthly as before. Residual activity remains with 100 % EIat least for 6 months.