THE MYCOBIOTA OF THE WEED MIKANIA-MICRANTHA IN SOUTHERN BRAZIL WITH PARTICULAR REFERENCE TO FUNGAL PATHOGENS FOR BIOLOGICAL-CONTROL

A survey of the fungi associated with the tropical weed Mikania micran tha was conducted during 1988 and 1989 in part of its native range in southern Brazil. Sampling was concentrated mainly in the state of Rio de Janeiro, covering 70 sites in different climatic or ecological zone s, Nine species were identified, including the recently described down y mildew species Basidiophora montana and the previously undescribed M ycosphaerella mikania-micranthae sp. nov. with its anamorph Septoria m ikania-micranthae. Asperisporium mikaniae comb. nov., Asperisporium mi kaniigena comb. nov., Pseudocercospora plunketii comb. nov., and Cerco spora mikaniacola are new records for Brazil. Field observations indic ate that Basidiophora montana has potential as a classical biological control agent of the weed in Old World subtropical or montane climates , whilst Mycosphaerella mikania-micranthae and the microcyclic rust Pu ccinia spegazzinii appear to be equally damaging to the host but to ha ve a wider climatic range and thus are highly promising agents for int roduction throughout the Palaeotropics.