The 1^st commercially exploited mycoherbicide is

The 1^st commercially exploited mycoherbicide is COLLEGO.
A mycoherbicide is an herbicide based on a fungus. As a biological agent, it works by producing toxic compounds that dissolve the cell walls of targeted plants". Unlike traditional herbicides, mycoherbicides can reproduce themselves and linger in the soil for many years to destroy replanted crops.
Collego is a wettable powder formulation of Collectotrichum gloeosporoids f. Sp. aeschenomene is used for controlling Northern joint with (Aschenomene virginica) in rice and soybean.