Non-chemical management of weeds through bioherbicides: current status, market, development, constraints and future prospects

Abstract

A weed, a kind of pest, is a plant growing where it is not desired, or a plant out of its place. Weeds are a major threat to biodiversity and agricultural productivity. The annual losses caused by weeds has been estimated to over US$26 billion in the USA, AU$ 3.3 billion in Australia and US$ 11 billion in India exclusively in 10 major crops. The rising awareness about the potential health risk with chemical residues among individuals and farmers, emphasis is on growing organic crops to keep us healthy and a long life. In addition, the constant use of herbicides in agriculture system also paves the way for the emergence of resistance of weed variety. Bioherbicides, an eco-friendly alternative to non-chemical management of weeds, are defined as the formulations based on indigenous living host-specific microorganisms and ancillary components applied in an inundative manner similar to chemical herbicides. The term microbial herbicide preferably be used for microbial-based formulations. These are derived from fungi, bacteria and viruses. The bioherbicides market is rapidly growing and expected to witness market growth at a rate of 15% and is expected to reach US$1.84 by 2029. In spite of all efforts, acceptance of bioherbicides by the users is low due to a wide range of constraints (e.g., environmental, technological, host-specificity, regulatory, funding and human-related). Environmental conditions playing a significant role on the microbial germination, penetration, infection and biocontrol efficacy of the target host. Twenty-six microbe-based herbicides have been developed globally. At present, 13 bioherbicides are available in the market namely DeVineTM, CollegoTM (LockdownR), BioMalR, BioChonTM, MycoTechTM, Chontrol™ (EcoClearTM), SmolderR, SarritorTM, SolvinixR, Gibbartrianth, BiophomaTM and Di-Bak ParkinsoniaR. For successful deployment of bioherbicides into agriculture, horticulture and forestry, in addition to boosting their market, scientists need to develop consumer-friendly bioherbicides with a long-shelf life, non-effected by environmental conditions, ability to control varied weeds in a crop, and with a biocontrol efficacy better than or at par with the synthetic herbicides. Objective of this review is to discuss biocontrol strategies for controlling weeds, phases of bioherbicide development, market, current global status, development of currently available bioherbicides, constraints/limitations in their production & demand and future prospects for their adoption in weed management system.