Duangdean Cheramakara. (1993) Laboratory investigation on efficacy of extract from sweetflag (Acorus calamus Linn.) rhizomes on brown planthopper (Nilaparvata lugens Stal.). Mahidol University,:ม.ป.ท.Duangdean Cheramakara. 1993. Laboratory investigation on efficacy of extract from sweetflag (Acorus calamus Linn.) rhizomes on brown planthopper (Nilaparvata lugens Stal.). ม.ป.ท.:Mahidol University,;Duangdean Cheramakara. Laboratory investigation on efficacy of extract from sweetflag (Acorus calamus Linn.) rhizomes on brown planthopper (Nilaparvata lugens Stal.). ม.ป.ท.:Mahidol University, 1993. Print.