Investigation of the Phytotoxic Effects of the Pyrethroid Tau-fluvalinate on Lactuca sativa (Asteraceae)

The increasing use of pesticides in recent years is considered a threat to the environment and health. The current study intended to assess the potential phytotoxic impacts of tau-fluvalinate, a pyrethroid pesticide, on Lactuca sativa (Asteraceae) using germination and seedling development endpoints. For this purpose, germination percentage, relative seed germination, relative root growth, and germination index were determined for L. sativa seeds exposed to five different concentrations of tau-fluvalinate (12, 24, 48, 96, and 192 mg/L) for 48 h. Statistically significant differences were observed among the tested concentrations in terms of germination percentage, root and shoot length, relative seed germination, relative root growth, and germination index (p < 0.0001). Based on the calculated germination indices, the concentration of 12 mg/L was classified as non-phytotoxic but moderately inhibitory, 24 mg/L as moderately phytotoxic, and 48, 96, and 192 mg/L as highly phytotoxic. These findings indicate that tau-fluvalinate may pose environmental risks due to its acute toxic, sublethal, and phytotoxic effects, particularly at high concentrations. Furthermore, the results confirm that L. sativa is a sensitive and reliable bioindicator for assessing the phytotoxicity of synthetic pyrethroids.