Assessment of the microcyclic rust Puccinia lantanae as a classical biological control agent of the pantropical weed Lantana camara

Abstract Lantana camara is a flowering shrub of the family Verbenaceae, native to the Americas which has become a major invasive weed in the Palaeotropics; affecting both natural and agricultural ecosystems. It has been the focus of classical biological control for over a century but has proven to be a problematic target because of its high genetic diversity. Here, we report on an aggressive pathotype of the microcyclic rust Puccinia lantanae collected in the Amazonian rainforest, which – based on greenhouse screening – is damaging to a wide range of biotypes of the L. camara complex. Host-range testing within the Verbenaceae and related plant families, involving leaf clearing and staining, showed the pathotype to be highly specific to L. camara sensu lato but with detectable symptoms in several other verbenaceous species. These results, together with a taxonomic re-appraisal of Puccinia lantanae, are discussed in relation to the potential of the rust as a classical biological control agent of L. camara. We conclude that this pathotype of P. lantanae is a valuable addition to the biological control armoury and posit that it should be especially successful in humid forest situations.