Exposure to Attractive Toxic Sugar Baits containing Piriproxyfen (ATSB-PPF) in surfaces reduces the number of eggs and larvae produced by Aedes aegypti (Diptera: Culicidae) females

ABSTRACT The significant role of Aedes aegypti as a vector of several arboviruses has intensified studies on vector control tools, including Attractive Toxic Sugar Baits containing Pyriproxyfen (ATSB-PPF). PPF is an insect growth regulator (IGR) that has been used to control immature mosquitoes, but it also has direct effects on female reproduction. This study evaluated the effect of physical exposure of Ae. aegypti females with ATSB-PPF on fecundity and fertility at different times before and after blood meal. Females were confined in cages impregnated with ATSB-PPF at different concentrations (5, 50, and 500 ppm). One group of females was exposed to the baits 24 and 48 hours Before the Blood Meal (BBM), and in the other group, exposure occurred 24 and 48 hours After the Blood Meal (ABM). The number of eggs laid, larvae, and pupation rate were analyzed. Exposure of Ae. aegypti females to ATSB-PPF bait 24 hours after the blood meal was able to reduce the number of eggs laid, especially at the higher concentrations used, but the number of larvae obtained was reduced regardless of the exposure time to ATSB-PPF, i.e., 24 hours before or after the blood meal, or the concentration of PPF used. No changes were observed in the number of pupae from larvae obtained from eggs laid by mosquitoes exposed to ATSB-PPF. Physical exposure of mosquitoes to sugar baits is sufficient to reduce the investigated reproductive parameters of Ae. aegypti.

Sugar Bait Composition Containing Ivermectin Affect Engorgement and Mortality of the Mosquito Aedes aegypti (Diptera: Culicidae).

Toxins and attractants have been studied and used in sugar baits for mosquitoes. However, little importance has been given to the combination of sugar concentration, bait composition, and their relationship with mosquito engorgement and mortality. Therefore, the present study evaluated the effects of three concentrations of sucrose on baits with and without an attractant (concentrated guava juice), on engorgement and mortality rates of adult Aedes aegypti (Linnaeus, Diptera: Culicidae). Toxic sugar baits (TSB) and attractant toxic sugar baits (ATSB) containing 10, 50, and 70% sucrose and 100 ppm ivermectin (IVM) were prepared to assess engorgement and mortality rates. Subsequently, different concentrations of IVM (0.312-100 ppm) in TSB and ATSB were prepared with sucrose concentrations of 10 and 70% to determine the lethal concentrations (LC50 and LC90) values. Engorgement on the baits was observed under a stereomicroscope, and mortality was followed up to 48 h after feeding. In general, more mosquitoes engorged on TSB regardless of the sugar concentration, while higher concentrations of sugar in ATSBs resulted in higher numbers of mosquitoes engorging. A large increase in the LC90 of IVM was observed for females feeding on ATSBs and TSBs with 70% sucrose relative to those feeding on baits with lower sugar concentrations. No such effect was observed for males.

Larvicidal activity of Maytenus guianensis (Celastraceae) against Aedes aegypti (Diptera: Culicidae).

INTRODUCTION: Bioprospection of plant products is used to discover new insecticides. METHODS: The larvicidal activity of ethanolic extract and triterpene (tingenone B) from the bark of Maytenus guianensis and their effect on pupation and emergence were evaluated against Aedes aegypti. RESULTS: Crude extract LC50 was 11.3 ppm and caused ejection of the larvae intestine; tingenone B LC50 was 14.8 ppm. Pupation was reduced by 20% and 10%, respectively; however, the emergence was not affected. CONCLUSIONS: The crude bark extract exhibited a higher larvicidal effect against the vector.

Larvicidal activity of Maytenus guianensis (Celastraceae) against Aedes aegypti (Diptera: Culicidae)

Abstract INTRODUCTION: Bioprospection of plant products is used to discover new insecticides. METHODS: The larvicidal activity of ethanolic extract and triterpene (tingenone B) from the bark of Maytenus guianensis and their effect on pupation and emergence were evaluated against Aedes aegypti. RESULTS: Crude extract LC50 was 11.3 ppm and caused ejection of the larvae intestine; tingenone B LC50 was 14.8 ppm. Pupation was reduced by 20% and 10%, respectively; however, the emergence was not affected. CONCLUSIONS: The crude bark extract exhibited a higher larvicidal effect against the vector.