Experiments were conducted under laboratory and screenhouse conditions of CanthoUniversityin order to determine the concentrate of  three kinds of weeds had good control blast disease and compare the effect of two methods seed soaking or seed coating with either plant extracts of Eupatoriumodoratum, Kalanchoe pinnata or Ageratum conyzoides. Experiments were carried out on Jasmine 85 rice cultivar and consist of 10 treatments  and four replications. The rice plants at 15 days after sowing were inoculated with Pyricularia grisea at the concentration of  50.000 spores/ml (3ml/pot). Data was recorded at 7 and 14 days after inoculation based on scale of  Pinnschmidt et al.1993. Results showed that seed soaking or coating by Ageratum conyzoides 4% or Eupatoriumodoratum 4% gave good control of rice blast disease.