LAUSR

The development of botanical insecticides for pest control in agriculture is an important challenge nowadays. The plant extract derived from tea leaves was evaluated for its insecticidal activity toward green peach aphid. Evaluation of the efficacy of different concentrations of tea extract formulation [250, 350, 450, 550, 1000 ppm plant extract + 5 vol% polysorbate 20 + 10% (v/v) oil] on green peach aphid with two methods, leaf-dipping and leaf-spraying methods, was performed. The chemical compounds of hydroalcoholic extract of tea were determined by GC–MS analysis and FTIR. The results of GC–MS showed that caffeine may be an insecticidal active component. Creaming and phase separation of the prepared emulsion was investigated as the quality control factors. After 10 days, no phase separation and no color change were observed. The results indicated that LC50 of tea extract formulation contact toxicity was 357.72 ppm for 48-h exposure. The increased concentration of plant extract formulation led to increased green peach aphid mortality percent. The results of laboratory bioassay have shown that tea leaf extract could be considered as a potential source for the development of a botanical insecticide for controlling aphid.