First report of Plumeria spp. rust caused by Coleosporium plumeriae in Louisiana and Malaysia and Catheranthus roseus, a new host of this rust.
Plumeria spp., native to tropical America, are popular small trees grown widely in tropical areas of the world and as potted plants elsewhere. P. rubra and P. obtusa cultivars and hybrids are most common. A rust disease of a Plumeria sp. (likely P. rubra based on pointed leaf tips, leaves more than 18 cm (7 inches) long, and high rust susceptibility) was observed in November 2008 and again in June 2009 on homeowner plants in Baton Rouge, Louisiana, USA. A survey of 5 Baton Rouge retail nurseries in September 2009 revealed that 87% (90 of 103) of the plumeria plants were heavily infected with rust. Early symptoms included numerous 1-mm chlorotic spots on adaxial leaf surfaces followed by leaf chlorosis, necrosis, and abscission. Based on morphological characteristics, molecular data, and pathogenicity tests (on plumeria plants and other Apocynaceae family members that included Allamanda cathartica, Catharanthus roseus (Madagascar periwinkle), Mandevilla splendens, Nerium oleander and Vinca major), the rust was identified as Coleosporium plumeriae. Plumeria rust was also observed on plumeria trees in urban landscapes in peninsular (Penang) and Bornean (Kota Kinabalu, Sabah) Malaysia in December 2007. Plumeria rust was first found on the island of Guadeloupe and then spread to Central and South America. It has been known from Florida since 1960 under the synonym Coleosporium domingense, but has not been reported elsewhere in the continental United States. In more recent years, plumeria rust has spread to Hawaii, many Pacific islands, India, China, Taiwan, Thailand, Australia, and Nigeria. This is thought to be the first report of plumeria rust from Louisiana and Malaysia and of susceptibility of another member of the Apocynaceae, Catharanthus roseus, to Coleosporium plumeriae.