Additions to the mycobiota of the invasive weed Miconia calvescens (Melastomataceae)

Abstract

Miconia calvescens (Melastomataceae) is a shrub or small tree native to the Neotropics that has become one of the worst invaders of forest ecosystems, particularly in Pacific islands such as Hawaii and French Polynesia. It has been a target for biological control for more than 10 y, both with arthropod and pathogen natural enemies. Until now Colletotrichum gloeosporioides f. sp. miconiae was the only organism to be used in biological control against this weed. This fungus was introduced both in Hawaii and in French Polynesia in the late 1990s/early 2000s, where it has caused some damage to the weed, but it became evident that additional agents are needed to achieve adequate control. Exploratory surveys for plant pathogens as potential biocontrol agents of M. calvescens were undertaken in Brazil, Costa Rica and Ecuador and yielded a diverse list of pathogens, including one phytoplasma, two nematodes, one oomycete and numerous fungi. A study including the description of five fungal species found attacking M. calvescens was published recently. Herein the following additional fungi also belonging to the mycobiota of M. calvescens are described: Hyalosphaera ornata sp. nov, Microsphaeropsis miconiae sp. nov., Myrothecium miconiae sp. nov., Phyllachora miconiiphila sp. nov., as well as Hyalosphaera miconiae, Lembosia melastomatum and Microsphaeropsis clidemiae, which are recorded here for the first time on this host. Although preliminary our observations of damage to M. calvescens caused by these seven fungal species did not indicate any potential for use in classical biological control.

• biological control
• fungal diversity
• Hawaii
• Hyalosphaera
• Microsphaeropsis
• Myrothecium
• Phyllachora
• taxonomy

This study is part of an master’s dissertation presented by J.L. Alves to the Departamento de Fitopatologia/Universidade Federal de Viçosa and was undertaken with financial support from USGS BRD Pacific Islands Ecosystem Research Center, National Park Service and the Research Corporation University of Hawaii, CNPq (Conselho Nacional do Desenvolvimento Científico e Tecnológico) and CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior). The authors acknowledge the Núcleo de Microscopia e Microanálise of the Universidade de Federal Viçosa for the use of equipment, with the technical support of C.A. Vanetti. The authors also thank J. Jaramillo for providing information on occurrences of M. calvescens in Ecuador and A.Y. Rossman and J.L. Bezerra for their help and suggestions in selected taxonomic issues.