Canadian Forest Service Publications

Biological control of weeds. 2001. Evans, H.C.; Frohlich, J.; Shamoun, S.F. Pages 349-401 in S.B. Pointing and K.D. Hyde, editors. Bio-exploitation of filamentous fungi. Fungal Diversity Research Series 6. Fungal Diversity Press, University of Hong Kong, Hong Kong.

Year: 2001

Issued by: Pacific Forestry Centre

Catalog ID: 18108

Language: English

Availability: PDF (request by e-mail)

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The history of biological control of weeds using fungi is outlined from the 1970s to the present. Two broad approaches are distinguished: classical (inoculative) and inundative (augmentative) biological control. The former involves the release of exotic, co-evolved fungal pathogens from the natural range of the target weed into the country or region where it is an alien. The principles, protocols and methodology under-pinning this approach are detailed. Thus far, over 20 fungal species, in the main biotrophs such as rusts, have been exploited for the control of invasive weeds. Despite early and spectacular successes, there has been a general reluctance to adopt this strategy for weed management. The reasons, including lack of public sector funding, absence of legislation and pathophobia, are discussed. However, there is still cause for optimism, since a range of fungi, including smuts and coelomycetes, are currently being exploited to control alien weeds. Inundative biological control, typically using facultative pathogens, is discussed for agricultural and environmental weeds, as well as for weeds in forestry. The steps involved in this approach, whereby indigenous pathogens are mass-produced and applied as formulated products (mycoherbicides), are outlined. For agricultural weeds, relatively few products have been commercialised and the problems relating to their marketing are discussed. Nevertheless, for forestry weeds, the exploitation of plurivorous, wood rotting fungi has shown promise. In this case, safety and risk assessment is based on epidemiological data, rather than on the host range screening which is central to classical biological control.