Herbicidal effects of n-hexane, ethyl acetate and methanol extracts of billygoat weed (Ageratum conyzoides L.) leaveson Amaranthus spinosus L. growth

ERIDA, G.; SAIDI, N.; HASANUDDIN; SYAFFRUDIN; SAMPIETRO, D.A.; AMIST, N.

ALLELOPATHY JOURNAL

ALLELOPATHY JOURNAL

Lugar: Rohtak; Año: 2021 vol. 54 p. 211 - 220

0971-4693

The herbicidal activity of Ageratum conyzoides L. extracts was evaluated on the weed Amaranthus spinosus L. The leaves of A. conyzoides were sequentially extracted with n-hexane, ethyl acetate and methanol. In pot culture, these extracts were applied to A. spinosus plants at concentrations of 5 % - 20 %. Positive and negative controls were 2,4-D (2,4-dichlorophenoxy-acetic acid) applied at 0.686 kg a.i.ha-1 and distilled water. The A. conyzoides extracts had variable effects on leaf area, and shoot and root dry weight and weed control (%) of A. spinosus. The ethyl acetate extract was most inhibitory than n-hexane extract, while the methanol extract had no effect. Twenty one days after application, the applied ethyl acetate extract at 20 % concentration completely controlled the A. spinosus similar to 2,4-D. Main constituents identified by GC-MS in ethyl acetate extract were: 1,8-cineole (3.90 %), caryophyllene (25.47 %), precocene II (59.22 %), and 2,6,10,14,18,22-tetracosahexaene (5 %). In n-hexane extract were: precocene II (16.63 %), neophytadiene (14.94 %), phytol (8.24 %), and α-Methyl linolenate (14.13 %) and in the methanol extract were: 1,8-cineole (3.78 %), precocene II (9.16 %), neophytadiene (20.6 %), phytol (14.12 %) and 9,12,15-octadecatrienoic acid methyl ester (9.36 %). The ethyl acetate extract proved promising to control the weed A. spinosus.