Herbicidal activity of eugenol towards some grassy and broad-leaved weeds

Abstract

The present study investigated the phytotoxic potential of eugenol, a major component from the essential oil of clove [Syzygium aromaticum (L.) Merrill and Perry], towards four grassy [Echinochloa crus-galli (L.) Beauv., Phalaris minor Retz., Sorghum halepense (L.) Pers. and Leptochloa chinensis (L.) Nees] and four broad-leaved [Ageratum conyziodes L., Commelina benghalensis L., Cassia occidentalis L. and Bidens pilosa L.] weeds. The effect of eugenol (50–1,000 μM) on the growth and development of seedlings after 7 days of treatment was studied in terms of percent germination, root and shoot length, total chlorophyll content and cellular respiration. Eugenol at 1,000 μM caused 55–70 and 42–90 % decrease in percent germination in grassy and broad-leaved weeds, respectively. Likewise, root length declined by 55–90 and 57–71 %, whereas shoot length was decreased by 50–83 and 36–73 % in grassy and broad-leaved weeds, respectively, in response to 1,000 μM eugenol. The observed reduction in the plant growth was accompanied by a decline in the total chlorophyll content (37–53 %) and cellular respiration (36–57 %) in the test plants. However, the inhibitory effect was stronger towards grassy weeds than towards the broad-leaved ones. Thus, future research can be focused on developing eugenol, a natural plant product, as an environmentally safe herbicide in replacement to the harmful chemical herbicides.