Evaluation of the insect growth regulator Pyriproxyfen against populations of Aedes aegypti from Trujillo, Venezuela

Abstract

Insect growth regulators have been proposed as an alternative for the control of insect pests because they interfere with normal development, mimicking juvenile hormone and molting hormone or interfering with chitin synthesis. The objective of this study was to evaluate the efficacy and persistence of Sumilarv 0.5 G (pyriproxyfen) at the doses 0.01 ppm and 0.05 ppm on Aedes aegypti populations from Trujillo, Venezuela. Bioassays were carried out with the immersion technique, using fourth instar larvae from three localities: Tres Esquinas, Paramito and Hatico and the Rockefeller strain for reference. In the Tres Esquinas population the percent inhibition of emergence (%IE) was 73.5% at 0.01 ppm and 94.7% at 0.05 ppm.  In the Paramito and Hatico populations the %IE were low (66 and 69%) at 0.01 ppm, and 79 and 77% at 0.05 ppm, respectively showing a higher efficacy of the compound at the higher dose used. The persistence of pyriproxyfen at 0.05 ppm over the course of the test yielded IE above 90% in all populations during the first four weeks after treatment and after eight weeks decreased to 59% in Tres Esquinas, 73% in Paramito and 83% in Hatico; the Rockefeller reference strain maintained an IE at 99%. Our results show the effectiveness and persistence of pyriproxyfen at the dose of 0.05 ppm suggesting its use for the control of Aedes aegypti in the study areas.