Phytotoxicity of Piper marginatum Jacq. essential oil on detached leaves and post-emergence of plants

ABSTRACT Essential oils used as bioherbicides are a promising alternative in agriculture. This study aimed to assess the phytotoxic potential of Piper marginatum essential oil through an in vitro study with detached and post-emergence leaves of three commercial species (lettuce, pepper, and tomato) and a weed (Spermacoce verticillata). The experiments were conducted in a randomized design with six treatments that consisted of four concentrations of essential oil (0.001, 0.01, 0.1, and 1% [v/v]) and two control treatments (distilled water, and 1% polysorbate 80 in distilled water). The P. marginatum essential oil had a phytotoxic effect on the leaves of the experimental species. The highest essential oil concentration resulted in greater toxicity effects on tomato, lettuce, and pepper leaves. The 0.1% essential oil concentration completely destroyed the S. verticillata leaves. Seven days after application, the P. marginatum essential oil did not show adverse effects on plant growth in the post-emergence phase. It is recommended to investigate its possible phytotoxic activity in other phases of plant development to understand its mode of action and potential as an alternative to developing bioproducts for weed control.