EFFECT OF TEMPERATURE AND STAGE OF DEVELOPMENT ON SUSCEPTIBILITY OF AEDES EUEDES AND AEDES STIMULANS (DIPTERA: CULICIDAE) LARVAE TO TEMEPHOS

Abstract

AbstractIn laboratory trials, the susceptibility of Aedes euedes Howard, Dyar and Knab and Aedes stimulans (Walker) larvae to temephos (Abate®), was positively correlated with increasing temperature. Early instar larvae were more susceptible than late instars. Susceptibility differed 36 times from the fourth instars at 4 °C (24 h LC50 = 16.92 ppb) to the first instars at 19 °C (24 h LC50 = 0.47 ppb) the extremes of instar and temperature tested. The minimum recommended dosage of temephos (6 ppb) was ca. 9 times the LC90 of first instar A. stimulans and A. euedes at 19 °C. By contrast, the 24 h LC90 of 67.4 ppb for the fourth instar of A. stimulans at 4 °C was ca. 4 times the maximum concentration of temephos (18 ppb) currently recommended for Aedes spp. control. However, in simulated pool studies, satisfactory control of A. stimulans was achieved by 72 h posttreatment at the highest recommended dosage.