Biotechnological Approaches for Weed Management

Biotechnology has provided new dimensions to herbicide technology. Transgenic technology has
generated herbicide-resistant crops (HRCs), which have had a profound impact on the herbicide
market. This same technology has the potential to make crops better competitors with weeds through
improving competitive traits or making the crop more allelopathic. Living bio control agents can
sometimes be applied to weeds, much like a herbicide. In the bio herbicide approach, microbial plant
pathogens are applied to target weeds. Fungi, bacteria and viruses offer great promise as
bioherbicides. Formulations of Phytophthora palmivora (De Vine) as a selective mycoherbicide for the
control of milk weed (Morreniaodorata) in citrus, and Colletotrichum gloeosporioides (Collego) for the
control of Northern joint vetch in rice and soybean, are now widely used in developed countries.
Extensive research has demonstrated that several allelochemicals possess good herbicidal activity.
Thus, A crop that is genetically engineered to be resistant to yet another selective herbicide must fulfill
a weed management need that is unmet, such as those niches that were filled by bromoxynil-resistant
crops.