First report of Uredo crepidis-japonicae and Septoria crepidis on Crepis japonica in Brazil

Abstract

Crepis japonica Benth is a herbaceous plant native from China and Japan which was recently introduced into Brazil, where it is disseminating rapidly and already has become an important weed in nurseries (Plantas Daninhas do Brasil, 3 ed., pg.146, 2000). In July 2000 a leaf rust was observed on C. japonica growing in a citrus (Citrus sp.) nursery situated in Vicosa, Minas Gerais State, Brazil. The fungus was identified as Uredo crepidis-japonicae Lindroth which has been reported only from Australia, Continental China, Formosa (Taiwan) and Japan (Rept. Tottori Mycol. Inst., n.08, pg.1, 1980). Irregularly oval shaped leaf lesions were dark-brown due to the presence of a powdery mass of uredospores (Figure 1A). Severely infected leaves were clorotic. Morphological features for this fungus were: uredia, 0.3 to 0.5 mm diam; uredospores spherical, 14 to 20 μm diam, pale brown, with 3 to 4 germ pores, and walls 1μm thick. U. crepidis-japonicae is the uredial stage of Puccinia crepidisjaponicae Dietel, but no teliospores were found in the material examined (VIC 22136). However, size and shape of uredospore alone suffices for distinguishing this species from other rust fungi on Crepis spp. (Table 1). In January 2001 another foliar disease on young and old leaves was also observed on C. japonica, at a different site in Vicosa. The inciting agent was identified as Septoria crepidis Vestrerg. (Syll. Fung., XIV, pg. 974, 1899) known from USA, Europe and Asia. Lesions were necrotic, irregular, pale-brown, 1 to 8mm diam. The fungus had immersed, globose pycnidial conidiomata (Figure 1B), 60 to 70 μm diam, pale-brown, ostiolate, conidiophores were absent; conidia were hyaline, filiform, multiseptate, 25 to 35 μm x 1.0 to 1.5 μm (VIC 22137). These are the first reports of occurrence of these fungi in Brazil. Both fungi were probably introduced into Brazil TABLE 1 Morphological characteristics of uredospores of rust fungi (Puccinia spp.) with uredial stage on Crepis spp.