Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

First report of downy mildew on Gynura aurantiaca caused by Plasmopora halstedii sensu lato in Florida.

Abstract

During February 2013, a local nursery submitted Gynura aurantiaca samples to the Florida Extension Plant Diagnostic Clinic in Homestead, Florida, USA, where 30% of 1000 plants were affected. Downy, white mycelium was observed on the abaxial leaf surface and the adaxial surface of affected leaves appeared darker in colour. Severely affected leaves began to curl as the tissue turned necrotic. The pathogen was identified as Plasmopara halstedii based on morphological, genetic (PCR) and pathogenicity analyses. This is thought to be the first report of P. halstedii causing downy mildew on G. aurantiaca.