Assessing the potential of fedaleh () essential oils as a natural herbicide for spring-summer crops.

Large quantities of chemical herbicides are used in agroecosystems every year, which not only imposes a significant financial burden on farmers but also leads to environmental pollution. To address this challenge, the present study aimed to replace Treflan with Fedaleh essential oils (EO). Treflan is a commonly used chemical herbicide for spring-summer crops, and has been chosen as a prevalent and abundant weed in many agricultural ecosystems. Four types of inhibitors, including Treflan herbicide and essential oils extracted from the leaf, stem, and flower of Fedaleh, were used in this experiment. These inhibitors were tested at five different concentrations: 0, 0.5, 1, 2, and 5 μL/mL. Based on GC-MS results, the key compounds found in Fedaleh EO were α-pinene, α-phellandrene, γ-terpinene, linalool, sabinol, β-myrcene, neric acid, carvacrol, β-phellandrene, thymol, and spathulenol. A dose-dependent increase in hydrogen peroxide, malondialdehyde, electrolyte leakage, and proline content was observed with Fedaleh EO or Treflan. However, a decline in cell viability, germination, radicle length, radicle weight, plumule length, plumule weight, and seedling vigor index was observed in a dose-dependent manner with Fedaleh EO or Treflan. The weight of the radicle and plumule was noticeably decreased by 27 %, 28 %, and 14 %, 19 % respectively when treated with essential oils derived from the stem and flower of the Fedaleh, as compared to Treflan. Interestingly, at concentrations of 5 μL/mL EO, the germination, radicle length, plumule length, and seedling vigor index significantly decreased by 64-72 %, 56-56 %, 41-44 % and 90-93 % % as compared with control, respectively. The essential oils extracted from different parts of Fedaleh showed no significant difference in terms of hydrogen peroxide, electrolyte leakage, cell viability, and proline content, compared to Treflan ( > 0.05). Compared to the control, Treflan did not affect germination ( > 0.05), but the EO of Fedaleh's different parts significantly inhibited germination ( < 0.05). The growth inhibitors at a concentration of ≥1 μL/mL significantly reduced the length of the radicle and plumule in . Overall, Fedaleh EO has significant potential as a growth inhibitor and oxidative stress inducer to prevent weed interference. This makes it a suitable option for the commercial production of a natural herbicide.