First Report of Leaf Spot of Smooth Bromegrass Caused by Pithomyces chartarum in Nebraska

Abstract

Smooth bromegrass (Bromus inermis Leyss.) is the most common perennial grass species cultivated for forage in North America. During late fall of 2004, smooth bromegrass plants in Lincoln, NE were observed to have brown lesions on leaf midveins that were several centimeters long. Symptomatic leaves were surface disinfested for 1 min in 2% NaOCl and incubated at 25°C on potato dextrose agar (PDA) and water agar. The fungus, Pithomyces chartarum (Berk. & Curt) Ellis, was isolated consistently and identified on the basis of morphological characteristics (1). Colonies were effused and black on PDA. Conidiophores measured 3.5 to 8 × 1.9 to 3.9 μm and were smooth and single. Conidia (7 to 25 × 9.5 to 14 μm) were broadly ellipsoidal, pale brown to dark brown, verrucose with mainly three transverse septa and one to two longitudinal septa. Pathogenicity tests were conducted on 50-day-old plants by spraying with a conidial suspension (2.5 × 105 spores per ml). Control plants were sprayed with sterile water. All plants were kept in a moist chamber (100% relative humidity) for 3 days and then transferred to a greenhouse (25°C, >70% relative humidity, and a 12-h photoperiod). One week after spraying, elongated lesions developed on leaf midveins of inoculated plants from which P. chartarum was consistently reisolated. No symptoms were observed on control plants. While P. chartarum has been described as a saprotroph or a parasite on a wide range of plants primarily in the tropics and subtropics, including the southern United States (2), it was reported previously on B. inermis only in Canada (3). This report expands the distribution and host range of P. chartarum as a pathogen in the United States. References: (1) M. B. Ellis. Dematiaceous Hyphomycetes. Commonwealth Mycological Institute, Kew, Surrey, England, 1971. (2) D. F. Farr et al. Fungal Databases, Systematic Botany and Mycology Laboratory, On-line publication. ARS, USDA, 2005. (3) J. H. Ginns. Compendium of Plant Disease and Decay Fungi in Canada 1960-1980. Res. Br. Can. Agric. Publ. 1813, 1986.

A history of facial eczema (pithomycotoxicosis) research

“…Pithomyces chartarum has been reported as a pathogen of aerial parts of rice and sorghum in africa and india (Sutton & Gibson 1977), of Cannabis sativa in india (Ponappa 1977), of brome grass in Nebraska (Eken et al 2006), of wheat in Hungary (Toth et al 2007), and of Withania somnifera in india (Verna et al 2008), but it is usually saprophytic and has been found on a wide range of decaying plant material and in soil and air. Prior to the discovery that it was the cause of facial eczema, it was recorded most often from africa and Malaysia, but not from New Zealand nor other temperate regions.…”

Characterization of Nuclear and Mitochondrial Genomes of Two Tobacco Endophytic Fungi Leptosphaerulina chartarum and Curvularia trifolii and Their Contributions to Phylogenetic Implications in the Pleosporales

“…Alamo, etc. [7][8][9][10]. However, of note, the fruiting bodies of this fungus have also been reported to cause facial eczema in some animals (i.e., sheep, cattle, goats, and deer) as a consequence of the liver damage caused by a mycotoxin (sporidesmin) [11][12][13].…”

The Eurotiomycete Apinisia graminicola as the causal agent of a leaf spot disease on the energy crop Miscanthus x giganteus in Northern Germany

“…This is in contrast to already known fungal pathogens of M. giganteus with previous reports about infection of other plant species. Pithomyces chartarum, causing leaf blight of M. giganteus (Ahonsi et al 2010), has also been reported to cause leaf spot of smooth brome (Bromus inermis) (Eken et al 2006) and leaf blight of wheat (Triticum aestivum) (Tóth et al 2007); Stagnospora tainanensis, infecting especially young M. giganteus leaves (Pusz and Pląskowska 2010), was previously described as the causal agent of sugarcane (Saccharum officinarum) leaf blight (Hsieh 1979); and several Fusarium species, including F. culmorum and F. graminearum as causal agents of Fusarium head blight in wheat (Osborne and Stein 2007), caused rhizome rot in M. giganteus (Scauflaire et al 2013). Also in our recent study, where we screened for M. giganteus leaf pathogens, all four identified filamentous fungi causing necrotic lesions have previously been reported as pathogens of Poaceae including wheat and maize (Falter and Voigt 2014).…”