Exploitation of Fungal Phytotoxin as Natural Herbicide for Ecofriendly Weed Management: Problems and Prospects

Abstract

Weeds are major problems in crop production, associated with reduction of crop plant growth, reduce the quality by competing for nutrients and water provided to crops and releasing chemicals that suppress crop growth. Current weed control largely relies on chemical herbicide. The increasing prevalence of both herbicide resistant weeds and bans on chemical herbicide use has created a strong option for development of novel method for weed control. Mycoherbicides include phytopathogenic fungi or fungal compounds or fungal cell free broths or fungal crude broth useful for weed control. The major barriers in the application of fungal spores are returns in investment, which may prohibit the development of highly expensive mycoherbicide, and registration may be impeded if safety and efficacy tests required by the environment protection agencies are too critical, dependency on environment conditions for infection and subsequent development are the major barriers for the application of fungal spores as herbicide. The phytotoxin that inhibit the germination and growth of weed species which are produced and released by fungi or other microbes are receiving increased attention for use as weed controls and as herbicides. Fungal phytotoxins often act as the initiator factor for successful pathogenesis. Several phytotoxins are known to be the determinant factor in pathogenesis. Various phytotoxins viz., tentoxin, AAL-toxin, auscaulitoxin aglycone, hydantocidin, thaxtomin and tabtoxin have the potential for use as herbicides. Fungal phytotoxins are great source for the development of new herbicides and offer ecofriendly alternative approach to weed control. The use of fungal phytotoxins has stimulated the search for alternative to chemical weed control. This review is to highlight the potential of fungal phytotoxin in the weed control, their current progress, problems and potential in their exploitation as Mycoherbicides.