The Effectiveness of Dibutyltin (IV) and Di-tert-butyltin (IV) Alkyl-phenyl Dithiocarbamate Compounds as Larvicide against <em>Aedes aegypti</em> Linn. (Diptera: Culicidae) in Laboratory

Abstract

Extensive use of insecticides to control dengue vectors has led to the development of mosquito resistance, environmental pollution and undesirable effects on non target organisms. Thus, the potential of organotin (IV) compounds has been explored to be developed as insecticides to obviate the existing problems. The aim of this study was to examine the larvicidal effect of dibutylt in (IV) and di-tert-butyltin (IV) alkyl-phenyl dithiocarbamate compounds against Aedes aegypti Linn. in laboratory. Larvicidal bioassay test of four compounds dibutyltin (IV) ethyl phenyl dithiocarbamate, di-tert-butyltin (IV) ethyl phenyl dithiocarbamate, dibutyltin (IV) butyl phenyl dithiocarbamate and di-tert-butyltin (IV) butyl phenyl dithiocarbamate against third instar larvae of A. aegypti was carried out. The study indicated that dibutyltin (IV) butyl phenyl dithiocarbamate showed the highest larvicidal effect with LC50 and LC90 values of 0.59 and 3.91 ppm, respectively. However, the other three compounds showed lower larvicidal effects. Dibutyltin (IV) ethyl phenyl dithiocarbamate showed moderate larvicidal effect with LC 50 and LC90 values of 4.45 and 11.08 ppm, respectively, followed by di-tert-butyltin (IV) butyl phenyl dithiocarbamate compound with LC50 and LC90 values of 5.08 and 11.50 ppm, respectively. Di-tert-butyltin (IV) ethyl phenyl dithiocarbamate compound showed the least larvicidal effect with LC 50 and LC90 values of 8.59 and 36.74 ppm, respectively. Morphological anomalies such as elongated neck region, shortened length and destructed digestive tract in the larvae were observed and recorded during the larvicidal bioassay testing. As a conclusion, dibutyltin (IV) butyl phenyl dithiocarbamate compound is the most effective compound against the dengue vector, A. aegypti and has the potential to be explored as a larvicide. Further study is needed to ensure that this compound can be used safely as a larvicide.