Abstract

Parthenium hysterophorus is an aggressive invasive weed that threatens agricultural productivity, biodiversity and ecological stability. This study explores the bioherbicidal potential of crude metabolites derived from endophytic Alternaria and Gibberella species as sustainable alternatives to synthetic herbicides. Fungal strains were isolated from the stems of Sageretia thea, identified based on morphological and microscopic characteristics, and cultured in a yeast extract-supplemented medium to enhance metabolite production. Crude extracts were obtained using ethyl acetate and evaluated for their weedicidal efficacy against P. hysterophorus under a Completely Randomized Design (CRD). The synthetic herbicide 2, 4-dichlorophenoxyacetic acid (2, 4-D) was used as a standard for comparison. The results revealed significant inhibitory effects of the fungal extracts on seed germination and seedling growth. The extract from Alternaria reduced germination by 60% and markedly suppressed shoot and root growth at concentrations ranging from 250 to 1000 μg/mL. The Gibberella extract demonstrated even greater potency, achieving complete inhibition of germination and growth at 1000 μg/mL. In contrast, 2, 4-D exhibited a gradual inhibitory effect but failed to completely suppress germination at the highest tested concentration. These findings highlight the promising potential of fungal metabolites as eco-friendly bioherbicides that can offer an effective and sustainable approach to managing P. hysterophorus.

Keywords: 2, 4-D, Bioherbicide, Fungal natural products, Sageretia thea, Slide culture technique, Weed management.