BIOHERBICIDES: RESEARCH AND RISKS

Abstract

Many microbes have bioherbicidal activity, and several phytopathogenic fungi and bacteria have been patented as weed-control agents. The phytotoxic components of most agents have not been elucidated, but some phytotoxins and other secondary compounds produced by such microbes may be toxic to mammalian systems. Furthermore, few rigorous assessments have addressed uptake, translocation, metabolism, and persistence of these phytotoxins (some of which have not been identified), or the environmental effects of repeated augmentative applications of these microorganisms on long-term impact, environmental fate, or interactions with other microbial communities. Generally, there is a lack of definitive research on the overall toxicological risk of bioherbicidal microorganisms to the degree achieved or required for synthetic herbicides. This article presents a brief overview of bioherbicides (microorganisms and/or their phytotoxins), with emphasis on the toxicity of certain bioherbicides, and general considerations of risks associated with bioherbicidal use. A subsequent article presents some of our research results and future research directions on efforts to develop the bioherbicidal fungus Myrothecium verrucaria as a safe and efficacious bioherbicide have been published elsewhere.

Keywords: :

• Bioherbicide
• phytotoxin
• microbial weed control
• mycotoxin regulation
• natural product toxicology
• phytopathogen
• secondary products
• trichothecene biosynthesis