Constraints in the Development of Bioherbicides

Bioherbicides are biological control agents applied in similar ways to chemical herbicides to control weeds. The active ingredient in a bioherbicide is a living microorganism and it is applied in inundative doses of propagules. Most commonly the microorganism used is a fungus and its propagules are spores or fragments of mycelium; in this case the bioherbicide is also referred to as a mycoherbicide. Commercial bioherbicides first appeared on the market in the USA in the early 1980s with the release of the product DeVine® in 1981 and in the next year, the release of the product Collego®. In spite of considerable public research effort and many promising candidate organisms, only one other bioherbicide product, BioMal®, has been registered (in Canada) since then. Furthermore none of these products are currently commercially available for a variety of reasons that will be discussed below.