INSIGHTFUL REVIEW OF BIOHERBICIDES DERIVED FROM PLANTS (PHYTO-HERBICIDES)

Abstract

ABSTRACT Weed control during crop cultivation with integrated management remains a challenge. Bioherbicides such as plant extracts, allelochemicals, and microbes, are alternatives for weed control in sustainable agriculture. There are a few studies on the physiological influence of plant and microbial biopesticides on the germination and growth of weeds. Weed seed germination or growth is hindered when plant metabolites or extracts are absorbed, damaging the cell membrane, DNA, mitosis, amylase activity, and other biochemical processes. Weed growth is slowed by decreased rates of root-cell division, food absorption, photosynthetic pigment synthesis, and plant growth hormone synthesis, while the production of reactive oxygen species, stress-mediated hormones, and erratic antioxidant activity is increased. Bacterially produced lytic enzymes and toxins degrade the endosperm and utilize it for survival, preventing the growth of weed seeds. Forty-six plant species were assessed as phytoherbicides against 43 weeds, belonging to 19 families and 42 genera. Lamiaceae was the most represented family (21.7%) due to their volatile oils and phytotoxic substances, which eliminate weed growth. Thymus, Eucalyptus and Pinus were the most represented genera. Thirteen species’ oils (38 %) and 21 species’ extracts (62 %) were used as herbicides. This review provides an overview of the physiological alterations on undesired weeds by using phytoherbicides, which is of the least studied eco herbicides, for sustainable agriculture outlined in the Sustainable Development Strategy 2030.