Since the late 1940s, synthetic herbicides have provided effective and economical control of many weeds. However, an excessive reliance on chemicals has created problems related to their overuse, such as toxic residues in plant and animal products and the pollution of soil and waterways. Furthermore, chemical herbicides fail to provide adequate control of some weeds, and increasingly stringent regulatory requirements for registration of new pesticides makes the development of new herbicides prohibitively expensive. These factors have lead to an increasing interest in the use of biocontrol agents to replace or augment traditional weed management systems. Biocontrol agents have less adverse effects on non-target species and are perceived by many to be more environmentally friendly than synthetic herbicides. They are also likely to provide greater operator safety than most synthetic herbicides, some of which have been shown to be carcinogens or have other adverse effects (Brown, 1992).There have been two main approaches to biocontrol of weeds using plant pathogenic fungi; the classical approach and the inundative (or bioherbicide) approach