Field evaluation of the pirimiphos-methyl as a larvicide

With respect to the importance of chemical control of malaria, the present study was conducted in order to evaluate the pirimiphos-methyl as a larvicide. In this respect, its stability, activity, and the interval between two treatments with pirimiphos-methyl were evaluated. This study was performed in artificial and natural breeding place at two villages in Kazeroon area. It was an experimental study. Having prepared the artificial breeding places, they were sprayed by concentrations of 12.5, 20, 25, 40, 50, and 80 gr/ha. Meanwhile, temphos, reldan and pirimiphos-methyl were compared in concentrations of 25, 22.5, and 25gr/ha, respectively. Bioassay test was used to evaluate the poison stability. The recorded mortality rate for Anopheles larvae were 91.7, 99.7, 100, 100, 100, and 100%, respectively. Results have revealed there was a significant statistically difference between the concentrations of 12.5 and 20gr/ha of pirimiphos-methyl, however, this difference did not reach the statistical significant between concentrations of 20gr/ha and higher. Reldan has shown a great larvicide activity. Temphos is quite safe but expensive, thus can not be widely used. On the other hand, Reldan is not biologically safe. Pirimiphos-methyl is a versatile, easy-to-handle, broad-spectrum insecticide of low toxicity to mammals. Further studies are needed to determine the rate of degradation of pirimiphos-methyl in natural breeding sites.