Field efficacy and non‐target effects of temephos granules against Culex pipiens (Diptera: Culicidae) and microorganisms in septic tanks, Republic of Korea

Abstract

A granular formulation of 1.0% temephos (temephos G) was tested for its efficacy in mosquito larval control, residual effects and effects on non‐target microorganisms. Culex pipiens complex in septic tanks in Yangsan, Republic of Korea were used for this study. Microorganisms in the same septic tanks were used for study of non‐target organisms. After the application of temephos G at the rates of 2.0 and 5.0 mg/L to selected septic tanks, mortalities were recorded for 50 days. The effect of temephos G on non‐target organisms was studied by evaluating its effects on the bacterial populations in the treated septic tanks. It was observed that using 1.0% temephos G at a rate of 2.0 mg/L resulted in 100% mortality against Cx. pipiens larvae by the eighth day after treatment. The residual activity of temephos G was observed to continue for a time; for example 29 days after treatment, average larval mortality rates of >68.0% were observed for both concentrations. At the 50th day after treatment, the mortality rates of the Cx. pipiens larvae were observed to decrease to below 42.7% for both concentrations. Application of temephos G did not have significant effects on the bacteria populations in the septic tanks. Since temephos did not seem to have any major effects on the microorganisms, it was concluded that it is a safe and effective larvicide to use in the septic tanks at a rate of 2.0–5.0 mg/L of 1.0% temephos G.

Predation and Control Efficacies ofMisgurnus mizolepis(Cypriniformes: Cobitidae) TowardCulex pipiens molestus(Diptera: Culicidae) and Fish Toxicity of Temephos in Laboratory and Septic Tank Conditions

“…It has been suggested that the chemical characteristics of septic tank water, such as DO and turbidity, did not seem to affect the abundance or the control of Cx. pipiens larvae in septic tanks (no description of septic tank systems) treated with temephos (Kang et al 2011). Temephos 5% granule applied at 10 ppm active ingredient (AI) to scrap tires was reported to provide 100% mortality of Aedes triseriatus (Say) larvae for 14 mo with a drop to 21% mortality after 21 mo (Beehler et al 1991).…”

“…However, application rate of 2 ppm (AI) of temephos 1% water soluble granule to EF of septic tanks resulted in 100, 68, and 43% mortality of Cx. pipiens larvae at 8, 29, and 50 DAT, respectively (Kang et al 2011), suggesting a need for repeated treatments for the effective mosquito control.…”

Assessment of selected larvicides for the control of Culex pipiens biotype pipiens and Culex pipiens biotype molestus under laboratory and semi‐field conditions

“…By contrast, several chemical insecticides that have been traditionally applied for mosquito control are banned or restricted in developed countries 3 . For example, one of the most commonly used larvicides worldwide is the organophosphate temephos, which can effectively control mosquito larvae by inhibiting cholinesterase enzyme activity in the acetylcholine receptors of the insect nervous system 8 . However, temephos use was phased out in the EU ~ 10 years ago leaving a gap in mosquito control 9,10 …”