Host-specific fungal plant pathogens offer significant opportunities for the classical biological control (biocontrol) of environmental weeds in Australia. Three recent cases of successful or highly promising fungal pathogen biocontrol agents are discussed: the white-smut fungus Entyloma ageratinae R.W. Barreto & H.C. Evans on mistflower (Ageratina riparia (Regel) R.M.King & H.Rob.); the rust fungus Baeodromus eupatorii (Arthur) Arthur on Crofton weed (Ageratina adenophora (Spreng.) R.M.King & H.Rob.); and the leaf-smut fungus Kordyana sp. on wandering trad (Tradescantia fluminensis Vell.). The mistflower white-smut fungus, now established across the range of the weed in eastern Australia, has been highly damaging on mistflower in many areas of New South Wales. Following extensive host-specificity testing, the Crofton weed rust fungus (ex. Mexico) was approved for release in Australia in May 2014. The fungus established readily in the field on the New South Wales South Coast and extensive defoliation of Crofton weed has been observed 6-12 months after release. A large-scale release program for this fungus, in partnership with the community, is currently underway across New South Wales. Host-specificity testing of the wandering trad leaf-smut fungus (ex. Brazil) is on-going in the CSIRO Canberra quarantine facility. Initial results are highly promising and it is hoped that this fungus will eventually be approved for release in Australia.
Morin, L. (2015) Using pathogens to biologically control environmental weeds – updates. Plant Protection Quarterly. 30(3), 82-85.