Kirramyces viscidus sp. nov., a new eucalypt pathogen from tropical Australia closely related to the serious leaf pathogen, Kirramyces destructans

Kirramyces destructans is a serious pathogen causing a leaf, bud and shoot blight disease of Eucalyptus plantations in the subtropics and tropics of South-East Asia. During surveillance of eucalypt taxa trials in northern Queensland, symptoms resembling those of K. destructans were observed on Eucalyptus grandis and E. grandis × E. camaldulensis. Phylogenetic and morphological studies revealed that the Kirramyces sp. associated with these symptoms represents a new taxon described here as K. viscidus sp. nov., which is closely related to K. destructans. Plantation assessments revealed that while E. grandis from the Copperload provenance, collected in northern Queensland, recovered from disease, E. grandis × E. camaldulensis hybrids from South America were highly susceptible to infection by K. viscidus and are not recommended for planting in northern Queensland. Preliminary results suggest the fungus probably originates from Australia. K. viscidus is closely related to K. destructans and causes a disease with similar symptoms, suggesting that it could seriously damage Australian eucalypt plantations, especially those planted off-site.

Ceratocystis atrox sp. nov. associated with Phoracantha acanthocera infestations on Eucalyptus grandis in Australia

Ceratocystis spp. include important pathogens of trees as well as apparently saprophytic species. Four species have been recorded on Eucalyptus grandis in Australia, of which only one, C. pirilliformis Barnes and M.J. Wingf., is known to be pathogenic. A recent survey of pests and diseases of Eucalyptus trees in northern Queensland revealed a species of Ceratocystis associated with the tunnels made by the aggressive wood-boring insect Phoracantha acanthocera (Macleay) (Cerambicydae: Coleoptera). The aim of the present study was to identify the fungus based on morphological characteristics and comparisons of DNA sequence data for three gene regions. The fungus peripherally resembles C. fimbriata Ell. and Halst. but differs from this species most obviously by having much darker mycelium, longer ascomatal necks, segmented hyphae and an absence of aleuroconidia. Comparisons of combined sequence data confirmed that the Ceratocystis sp. from P. acanthocera represents an undescribed taxon, which is provided with the name Ceratocystis atrox sp. nov. C. atrox appears to have a close relationship with P. acanthocera, although its role in the biology of the insect is unknown and its pathogenicity has not been considered.

Tan spot: A new disease of pyrethrum caused by Microsphaeropsis tanaceti sp. nov

The isolation frequency of Microsphaeropsis sp. in spring in association with necrotic lesions on leaves in Tasmanian pyrethrum (Tanacetum cinerariifolium) fields has increased substantially since first identification in 2001. Examination of morphological features and sequencing of the internal transcribed spacer region (ITS) resulted in the identification of a new species, herein described as Microsphaeropsis tanaceti sp. nov. The pathogenicity of three M. tanaceti isolates to two pyrethrum cultivars was confirmed by inoculating glasshouse-grown plants in three experiments. No significant differences in the susceptibility of the two cultivars to infection by M. tanaceti were found. Symptoms were tan-coloured spots which coalesced around the margins of the leaves. Therefore, the name 'tan spot' is proposed for this new disease of pyrethrum. The sensitivity of seven M. tanaceti isolates to difenoconazole and azoxystrobin, commonly used fungicides for the management of foliar diseases in spring, was assessed under in vitro conditions. Sensitivity testing for difenoconazole was conducted using a mycelial growth assay on potato dextrose agar, whilst testing for sensitivity to azoxystrobin used a conidial germination assay on water agar. Microsphaeropsis tanaceti was found to be more sensitive to azoxystrobin than difenoconazole, with complete inhibition of conidial germination at concentrations above 0.625 µg a.i. mL-1. By comparison, concentrations of 50 µg a.i. difenoconazole mL-1 or greater were required for significant inhibition of mycelial growth. It therefore appears likely that there is currently some control of tan spot as a result of the use of azoxystrobin and to a lesser extent, difenoconazole, for the control of other diseases.

The rusts on Proteaceae, including Puccinia grevilleae sp. nov. from northern Australia

The first rust fungus recorded on Grevillea in Australia is described as Puccinia grevilleae. A key is provided for all rusts occurring on the Proteaceae.

The smut fungi (Ustilaginomycetes) on Triodia, including Ustilago lituana sp nov from Australia

A new smut fungus, Ustilago lituana, is described and illustrated on the grass Triodia epactia from Western Australia. It is compared with the three known smut fungi on Triodia and a key for identifying these species is given.

Bibulocystis gloriosa sp nov (Pucciniales) on Caesalpinia scortechinii in Queensland, with comments on Spumula caesalpiniae

A rust causing leaf spotting and distortion of twigs and branches of Caesalpinia scortechinii in Queensland is described as the new species Bibulocystis gloriosa. Uredinia and telia occur on spotted pinnules, and pycnia, aecial uredinia and telia on galled and twisted leaf rachides, twigs and branches. B. gloriosa is similar to Bibulocystis viennotii on Albizia granulosa in New Caledonia in having a macrocyclic life cycle with all spore states, and teliospores with two fertile cells and two cysts. It differs in having aecial urediniospores and urediniospores with uniformly thickened walls and several scattered germ pores, rather than the apically thickened walls and equatorial germ pores of B. viennotii. Teliospores in the two species are similar in size, but those of B. gloriosa have proportionally larger fertile cells and smaller cysts than in B. viennotii. To date, B. gloriosa is known from only two localities in south-eastern Queensland. Comparison with the type specimen of Spumula caesalpiniae on Caesalpinia nuga from Indonesia has shown that the two rusts are generically distinct.

Annellosympodia orbiculata gen. et sp. nov. and Scolecostigmina flagellariae sp. nov. from Australia

Two new fungi, Annellosympodia orbiculata and Scolecostigmina flagellariae, on Acacia ligulata and Flagellaria indica, respectively, from Australia are described and illustrated. The former species is placed in the new genus Annellosympodia, which is characterised by an unusual combination of features, viz. fasciculate conidiogenous cells (conidiophores reduced to conidiogenous cells), holoblastic conidiogenesis with sympodial, but rectilinear proliferation leaving annular structures and lateral conspicuous conidiogenous loci, and rhexolytic conidial secession. The generic placement of these two fungi is discussed.

Oidium perseae-americanae sp. nov. on avocado

Oidium perseae-americanae is described causing powdery mildew on avocado (Persea americana) in New Caledonia and Brazil.

Austropleospora osteospermi gen. et sp nov and its host specificity and distribution on Chrysanthemoides monilifera ssp rotundata in Australia.

Hendersonia osteospermi was found for the first time in Australia on leaf spots of the introduced invasive plant Chrysanthemoides monilifera ssp. rotundata (bitou bush) in coastal regions of New South Wales. Pathogenicity tests on species from 11 tribes in the family Asteraceae, demonstrated that H. osteospermi caused severe necrosis on leaves and stems of C. monilifera ssp. rotundata and its congener C. monilifera ssp. monilifera (boneseed). Small necrotic spots also developed on Osteospermum fruticosum and Dimorphotheca cuneata in the Calenduleae and on Helianthus annuus (sunflower) in the Heliantheae. None of the other plant species tested developed leaf spots, although H. osteospermi was re-isolated from senescent leaves of Cynara scolymus (globe artichoke) in the Cynareae and Vernonia cinerea in the Vernonieae. Single ascospores from ascomata of a Pleospora-like fungus found on diseased stems of bitou bush produced H. osteospermi in culture, which proved the anamorph/teleomorph connection. The ITS region of both a single-ascospore isolate and a single-conidium isolate were sequenced and found to be identical. The taxonomic status of H. osteospermi is re-examined and Austropleospora osteospermi gen. et sp. nov. is described as its teleomorph based on morphology, host range tests and DNA sequence analysis. The potential of A. osteospermi for the biological control of bitou bush and boneseed in Australia is discussed.

Ramichloridium spp. on Musa in northern Queensland: introducing Ramichloridium ducassei sp. nov. on leaf streaks of Ducasse banana.

The fungi associated with tropical leaf speckle diseases of banana (Musa spp. and cultivars) in northern Queensland were examined from fresh leaves and herbarium specimens. Ramichloridium biverticillatum was predominantly found associated with leaves of Cavendish banana (Musa acuminata cv. Cavendish) and a new species, R. ducassei was found associated with dark brown streaks on leaves of Ducasse banana (Musa acuminata x balbisiana cv. Pisang awak). A key is provided for all of the species of Ramichloridum that are known to occur on Musa.

Omnidemptus affinis gen et sp. nov., teleomorph of Mycoleptodiscus affinis sp. nov

Omnidemptus is described as a new monotypic genus of ascomycetes and O. affinis isolated from leaves of Panici effusi var. effusi in Queensland, Australia, is shown to have as its anamorph a new species of the hyphomycete genus Mycoleptodiscus, M. affinis.

Cochliobolus heliconiae sp nov (Ascomycota)

A new species of Cochliobolus, C. heliconiae, is described and illustrated. The species is heterothallic and ascomata were produced in pure culture using two isolates of its Bipolaris anamorph, also described as new, obtained from lesions on Heliconia spp. in northern Australia.

Paliphora intermedia sp nov from Australia

Paliphora intermedia sp. nov. (Hyphomycetes) from unidentified leaf litter collected in Queensland, Australia is described and compared with the two other species in the genus.

Sphaerophragmium quadricellulare sp nov (Mycota, Uredinales) on Acacia in Australia, with brief notes on some related rust genera

A telial rust on leaves of Acacia pennata ssp. kerrii from Cape York Peninsula is described as Sphaerophragmium quadricellulare sp. nov. No other spore stages have been observed. Brief notes on other related rusts occurring in Australia are given.

Emended description of Anomalomyces ( Ustilaginales), including Anomalomyces yakirrae sp. nov. on Yakirra pauciflora (Poaceae) from Australia

An emended description of the genus Anomalomyces is given to accommodate a new species of smut fungus, Anomalomyces yakirrae, on Yakirra pauciflora ( Poaceae) from Australia. The systematic placement of the fungus within the genus Anomalomyces is based on morphological characters and molecular data from two loci.