First report of a rust disease of plumeria caused by Coleosporium plumeriae in Southern China and Vietnam

Abstract

A rust of Plumeria spp. was found in Southern China (Yunnan Province in 2003 and Hainan Island in 2006) and in Vietnam in 2010. Orange to yellow uredinial sori appeared on the lower leaf surface and then spread to the whole leaf. The leaf infection resulted in early abscission and many branches without leaves were frequently observed in affected trees that finally died. Specimens were collected and morphological observations carried out with light and electron microscopy to identify the causal rust fungus. Uredinia were hypophyllous and produced under the epidermis. Urediniospores were catenulate, globose, ovoid or ellipsoid, sometimes angular in shape, and 20.0-42.0 x 14.1-25.6 micro m in size. Their walls were verrucose and 1.3- to 3.2- micro m thick. These morphological characteristics agree with those of C. plumeriae except telia were not found in the specimens. This is thought to be the first report of this rust fungus from China and Vietnam.