Phytotoxicity of Callistemon viminalis essential oil against some weeds

Abstract

The present study investigated the phytotoxic potential oil Callistemon viminalis essential oil against some weeds viz. Ageratum conyzoides, Sorghum halepense, Leptochloa chinensis and Commelina benghalensis in order to assess its herbicidal activity. The laboratory bioassay revealed that Callistemon oil (0.025-0.1 %) decreased the emergence and early growth of test species in a dose-dependent manner. At 0.1 % Callistemon oil treatment none of the seeds of C. benghalensis germinated. The Callistemon oil not only affected the germination and early growth of weed species but also severely decreased the chlorophyll content of the test plants. The chlorophyll content decreased by ~ 71% in C. benghalensis in response to 0.05 % Callistemon oil treatment. These results strongly indicate the adverse effect of Callistemon oil on photosynthesis of test plants. Based on the study, it can be concluded that Callistemon oil possess phytotoxic potential and can be used as bioherbicide in weed management programmes.