Herbicidal Activities of Seven Native Plants on the Germination and Growth of Phalaris minor,Echinochloa crusgalli,Portulaca oleracea and Lactuca sativa

Plant extracts could turn out to be herbicides used in weed control. We evaluated the herbicidal effect of seven plants from the Al-Qassim Region of Saudi Arabia on germination and growth of Phalaris minor, Echinochloa crusgalli, Portulaca oleracea and Lactuca sativa. In the laboratory, plant extracts at 5, 10, 20 and 40 g/L inhibited the germination and seedling growth of test seeds. P. minor and P. oleracea were more sensitive to the extracts than L. sativa and E. crusgalli. The germination of either P. minor or P. oleracea were completely inhibited by Prosopisjuliflora at 10 g/L and by Rumex vesicarius and Teucrium baccatus at 20 g/L. Extract of Pulicaria undulate completely inhibited germination of target seeds at concentrations ranged from l 0 g/L to 40 g/L. The rank order of bioactivity was Prosopis jul（17ora 〉 Pulicaria undulata 〉 Rumex vesicarius 〉 Withania somnifera 〉 Teucrium baccatus 〉 Artemisia monosperma 〉 Anvillea garcinii. In the greenhouse trial, the extracts of seven plant species at 30, 60 and 90 g/L reduced growth of six-weeks-old target plants. Anvillea garcinii and Prosopisjuliflora showed the greatest effects. At 90 g/L, the reduction in the growth of target species reached between 20% and 30% for Anvillea garcinii and between I 1% and 25% for Prosopis juliflora. Overall, Prosopis juliflora, Pulicaria undulata, Anvillea garcinii and Rumex vesicarius had potential for use as natural herbicides or for development as novel plant-derived herbicides.