Chemical Characterization and Phytotoxicity of Foliar Volatiles and Essential Oil of Callistemon viminalis

We investigated the chemical composition and phytotoxicity of foliar volatiles (directly released from the macerated leaves) and essential oil extracted from the leaves of Callistemon viminalis against four weed species. Essential oil (EO) and foliar volatiles caused reduction in germination, seedling growth and dry matter accumulation in Bidens pilosa, Cassia occidentalis, Echinochloa crus-galli and Phalaris minor. Bidens pilosa was found to be the most sensitive towards foliar volatiles and EO, whereas C. occidentalis was the least sensitive. The chemical analyses of foliar volatiles and EO revealed the presence of 1,8-cineole and alpha-pinene as the main monoterpenes. The study concludes that volatile components of C. viminalis possess phytotoxicity against weeds and thus may hold promise for the management of weeds under sustainable agriculture.