Melampsora allii‐fragilis f. sp. galanthi‐fragilis reported for first time to cause rust on Galanthus plicatus in Latvia

Abstract

In Europe, Melampsora allii-fragilis f. sp. galanthi-fragilis (syn. Melampsora galanthi-fragilis) has been reported on leaves of snowdrop (Galanthus nivalis) in Romania (Savulescu, 1953; Bagyanarayana, 2005) and on Galanthus plicatus in Ukraine (Gutsevich, 1952). The GBIF Database has additional records of this fungus on G. nivalis from Austria, Czech Republic and France but the USDA SMML Specimens Database has also records from Hungary and Poland. According to this database, the established distribution area of M. allii-fragilis f. sp. galanthi-fragilis is ‘Central Europe’. Melampsora allii-fragilis f. sp. galanthi-fragilis belongs to the heteroecious rust fungi that require two hosts to complete their life cycles, and includes five spore stages. The telial hosts are willows Salix fragilis, S. fragilis · pentandra and S. pentandra but the aecial host is Galanthus (Saccardo et al., 1925; Bagyanarayana, 2005). Melampsora allii-fragilis f. sp. galanthi-fragilis is a newly recognized forma specialis that resembles M. allii-fragilis morphologically but differs in having Galanthus as its aecial host (Bagyanarayana, 2005). In May 2009, snowdrops (G. plicatus) showing symptoms of rust were found in the Botanical Garden of University of Latvia in Riga, Latvia. A specimen of infected snowdrop leaves (F.1. 8616) was deposited in the herbarium of the Faculty of Biology University of Latvia (RIG). Symptoms were small orange pustules (aecia) of about 0AE7–1AE7 mm in diameter on the undersides of leaves. Tiny yellow aecia of about 1AE0–1AE5 mm in diameter appeared concurrently on the upper sides of leaves. The aecial state of this rust under light microscopy had the morphology of M. allii-fragilis f. sp. galanthi-fragilis (Saccardo et al., 1925; Bagyanarayana, 2005): aecia hypophyllous, yellow or orange, aeciospores globose or ellipsoid, 17AE4–24AE6 · 14AE5–21AE7 lm in size. This is the first report of Melampsora allii-fragilis f. sp. galanthi-fragilis causing rust on Galanthus plicatus in Latvia.