M. C. Rombach

Metarhizium album, a fungal pathogen of leaf- and planthoppers of rice

Metarhizium album, a name widely regarded as a synonym of M. anisopliae, is restored for a fungus collected on plant- and leafhoppers (Homoptera : Auchenorrhyncha) from rice. In the Philippines and Indonesia it caused epizootics in populations of Nephotettix virescens and/or Cofana spectra, respectively. A single collection on an unidentified leaf hopper from mango is reported. Comparison of types revealed that M. brunneum is a synonym of M. album; the species is characterized by the pale brown colour of its conidial masses, clavate phialides (10–12.5 × 2–3.5μm), ovoid to ellipsoidal conidia ((3–4)4–6 × 1.5–2.5 μm) and growth of bulging masses of hyphal bodies rather than mycelium prior to sporulation. The primary taxonomic criteria for delimiting species of Metarhizium are the shapes of conidia and conidiogenous cells, presence or absence of a subhymenial zone of swollen hyphal bodies, and whether conidial chains adhere laterally to form prismatic columns. The occurrence of many natural and artificial colour variants of Metarhizium species suggests that colours of conidial masses and mycelium have only secondary taxonomic value. Conidial size is useful in delimiting varieties. A synoptic key to the taxa of Metarhizium is provided.

Torrubiella ratticaudata sp. nov. (Pyrenomycetes: Clavicipitales) and other fungi from spiders on the Solomon Islands

Torrubiella ratticaudata sp. nov. is described from salticid spiders from the Solomon Islands. The anamorph of this fungus, Gibellula clavulifera var. alba var. nov., produces ovoid conidia on phialides on penicilloid conidiophores and bacilliform conidia from polyblastic conidiogenous cells arising directly from the mycelium. Both teleo- and anamorphic states occur on spiders bearing a single, whiplike fungal stroma projecting from the tip of the hosts abdomen. Gibellula is extended and emended to include species of Granulomanus, which is regarded as a synonym of Gibellula. The different conditions under which morphologically distinct synanamorphs may reasonably be amalgamated in a single genus or should be retained in separate genera are discussed. Nomuraea atypicola and Gibellula pulchra were also found on the spiders; no teleomorphic state for either of these species was present.