Abstract – Classical biological control of Rubus niveus in Galapagos – the on-going search for suitable agents

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Abstract

Rubus niveus (Rosaceae, subgenus Idaeobatus), native to the Himalayas and erroneously called Mysore raspberry (‘mora’ in Spanish), has been the target of a classical biological control (CBC) programme for Galapagos since 2014. Invasive on five of the larger islands in the archipelago, R. niveus impacts severely on farmland and on biodiversity, particularly threatening endemic Scalesia (daisy tree) species and their unique ecosystem. As part of an integrated management strategy, CBC aims to complement current manual and chemical control measures. With native members of the Rosaceae absent, and only one commercially important introduced Rubus species present in Galapagos, R. niveus is an ideal target for CBC. The focus has been on fungal pathogens, primarily Phragmidium rust species associated with R. niveus in its native range. However, most rust species/pathotypes sourced to date have been shown to be non-infective to the biotype of R. niveus invasive in Galapagos, whilst others are insufficiently virulent or need an alternate host to complete their life cycle. In contrast, a leaf-spot pathogen belonging to the genus Septoria (Mycosphaerellaceae), found to be damaging on R. niveus in Pakistan, causes severe disease symptoms on the Galapagos weed biotype under quarantine greenhouse conditions and is currently under evaluation. This talk gives an overview of the fungal pathogens studied so far, as well as an update of research on the Septoria leaf-spot and future project plans.

keywords 

Invasive alien weed 

fungal pathogens 

Phragmidium rust 

Septoria leaf spot 

integrated management strategy 

Highlights 

Classical biological control (CBC) as management strategy for invasive Rubus niveus on Galapagos 

Focus for CBC agents of Rubus niveus is on fungal pathogens from the Himalayas 

Septoria leaf-spot pathogen ex Pakistan under evaluation as potential CBC agent for Rubus niveus