Acute toxicity of sodium chloride to first and fourth instar <i>Aedes albopictus</i> larvae

Abstract

e increase in the number of imported cases of dengue fever in Japan is of particular concern as Aedes albopictus is a vector of dengue fever. Due to the potential for insecticide resistance and the impact of insecticides on non-target species, increased attention is being paid to alternative methods of pest control. Placing salt in used tires has been recommended by the Ministry of Health, Labor and Welfare in Japan as a means of controlling mosquitoes. However, the e ectiveness of salt as a larvicide against Ae. albopictus are currently unclear. is study examined the acute toxicity of sodium chloride against rst and fourth larval instars of Ae. albopictus. Acute toxicity tests were conducted according to World Health Organization guidelines. e susceptibility of Ae. albopictus larvae was tested against 0.25%, 0.5%, 0.75%, 1.00%, 1.25% and 1.5% NaCl solutions. Larval mortality was correlated with an increase in NaCl concentration and exposure duration. First instar Ae. albopictus larvae were more sensitive to NaCl than fourth instar, and 72-h LC 90 values for rst and fourth larval instars were 0.49% and 1.01% NaCl, respectively. Our results suggest that the application of 0.5% NaCl to a habitat for 3 days is e ective for Ae. albopictus control.

An Experimental Evaluation of Toxicity Effects of Sodium Chloride on Oviposition, Hatching and Larval Development of Aedes albopictus

“…These findings indicated that the 3rd-4th instar larvae could be more susceptible to NaCl concentrations, which might be the cumulative toxicity effects attributed to longer exposure to the NaCl solution. Our experiments showed that LC95 of NaCl concentration on the 3rd-4th instar larvae was 11.4 g/L (1.14%), similar to previous studies [19]. Furthermore, taking the cumulative toxicity effects on a whole life cycle of Ae.…”

An Experimental evaluation of acute toxicity of Sodium Chloride against Aedes aegypti (Linnaeus) larvae

“…albopictus rst instar larvae were more susceptible to NaCl than fourth instar(Jinguji et al 2021) but our results indicated that the 3rd-4th instar larvae could be more susceptible to NaCl concentrations, possibly as a result of cumulative toxicity brought on by prolonged exposure to the Sodium Chloride solution which is at par with the recent studies conducted at China(Guo et al 2022). Our experiments showed that in 24 hours, LC50 and LC90 of NaCl concentration on 3rd-4th instar larvae was 2.27 and 1.32% respectively which is similar to previous studies(Jinguji et al 2021). These toxicity values suggested that if 2.27% concentration of NaCl is applied in larval habitat like used tyres, ower pots, 90% of larvae would be killed within one day.In our present study, when Ae.…”

“…In this regard, most common inorganic salt i.e., Sodium Chloride (NaCl) in aquatic habitats is worth being explored. Some Government Health Ministries in Japan have also suggested the application of salt in the possible mosquito habitats to kill their larvae (Jinguji et al 2021). It has been reported that saline water with more than 0.5% NaCl concentration act as an oviposition repellent in Aedes albopictus females (Jinguji et al 2020).…”