Herbicidal Activity of Coumarin When Applied as a Pre-plant Incorporated into Soil

Due to having a short half-life and novel site of action, the herbicidal potential of natural compounds are lionized. Coumarin is a secondary metabolite from Lavandula sp., family Lamiacae. The impact of eight concentrations of coumarin (0, 100, 200, 400, 800, 1600, 3200 and 6400 ppm) were separately used as a pre-plant incorporated into soil on six plant species under greenhouse conditions. Generally, coumarin had phytotoxic effect against all plant species. The phytotoxic effect was concentration-dependent. The high concentrations could inhibit the emergence of seedlings (probably by stopping germination of seeds). Based on ED50 parameter, the ranking of plant species for tolerance to coumarin was S. halepense > Z. mays > C. album > A. retroflexus > E. cruss-gali > P. oleracea. Based on selectivity index, coumarin at a concentration of 365.69 ppm can control P. oleracea without damaging Z. mays, whereas any concentration it cannot control other weeds without damaging Z. mays.