With increasing intensification of forest management and limited options for control of competing vegetation, there is need for research on alternative vegetation management methods, including biological control. Most forest weeds in Canada are native species with useful as well as detrimental roles, and therefore classical biological control with introduced natural enemies generally cannot be considered. At present, use of native fungal pathogens, or mycoherbicides, is one of the most promising approaches, and recent advancements in agriculture indicate that effective, site-specific controls using mycoherbicides are possible. Mycoherbicide use in forestry appears attractive because of the likelihood of fewer off-target effects than present vegetation management methods and because it could provide either selective controls for specific weeds or broad spectrum controls.Vegetation management in forestry has some unique aspects which will make the development of biological controls different from that in agriculture. There are many indigenous plant pathogens that are potential mycoherbicides, but their efficacy will need to be enhanced by adjuvants, stress treatments, and integration with other vegetation control practices. Currently, at three Canadian institutions and several other locations worldwide, there are research programs on biological control of forest vegetation.
Limited host range in the idiobiont parasitoid Phymasticus coffea, a prospective biological control agent of the coffee pest Hypothenemus hampei in Hawaii