Mycelial interactions on Hagem agar between 156 isolates of Stereum sanguinolentum obtained from wounded Picea abies or from slash in 12 sample plots located in Sweden, Finland and Lithuania revealed 97 vegetative compatibility groups (VCGs). Of the 23 VCGs that consisted of two or more (maximum, 23) isolates, 13 came from different sample plots, and sometimes from two or all three countries, whereas 10 were confined to a single sample plot. Some variation was observed in cultural characteristics among isolates belonging to the same VCG. Within a sample plot compatible isolates were randomly distributed indicating that distances up to 180 m in a forest stand have little influence on spread of S. sanguinolentum VCGs. Proportions of compatible pairings decreased among isolates collected within the bigger spatial scale. Occurrence of compatibility and consequent grouping of the isolates into VCGs was more pronounced in Swedish populations then Finnish and Lithuanian populations.

Ancorasporella mexicana gen. et sp. nov., collected on the dead leaf stalk of an unidentified fern in a cloud forest in the state of Veracruz, México, is described and illustrated. This singular hyphomycete is distinguished from known genera by its euseptate, triangular or fusiform conidia which are attached at 90° to the long axis of the cicatrized conidiogenous cell.

The saprotrophic wood-degrading abilities of strains from the intersterility groups S and P of the necrotrophic root and white rot fungus Heterobasidium annosum were tested using a conventional soil jar method and small wood blocks of Pinus sylvestris, Picea abies and Betula verrucosa. Weight loss in dry matter of wood blocks was compared with the ability of the same strains to secrete the phenol oxidase laccase under liquid and solid-state culture conditions. Results showed the much greater ability of H. annosum P strains to degrade wood, with weight losses comparable to those reported for other white rot fungi cultivated under similar conditions. In contrast, the S isolates except Br228 and Fr154 degraded the wood blocks poorly with a maximum weight loss of ca 12% recorded after 5 mo incubation. Light and scanning electron microscopy showed hyphal colonization and decay to be typical for white rot, with both simultaneous attack by cell wall thinning and preferential lignin degradation recorded for P strains. Results for wood block degradation correlated well with the ability of the intersterility groups to produce laccase in liquid culture and solid-state culture conditions, with P strains producing ca 5–6 times more laccase than S strains. Results indicate that great differences exist between H. annosum intersterility P and S groups ability to cause wood decay, but that P strains have a significantly greater competitive saprotrophic wood-degrading ability than previously realized.

The genetic relatedness of twenty isolates of Paecilomyces farinosus was determined by comparison of the products of polymerase chain reaction amplification of anonymous regions of genomic DNA with single arbitrary sequence oligonucleotide primers (RAPD analysis). Isolates were collected from seven insect species in eastern Canada and they differed greatly in cultural and morphological phenotype. All P. farinosus isolates were clearly distinguished from three other entomopathogenic fungi, including P. fumosoroseus. RAPD banding patterns did not, however, correlate with ecological backgrounds or morphological phenotypes of P. farinosus isolates. These observations support the conclusion that P. farinosus from eastern Canada is not composed of strains which can be separated on the basis of the ecological or morphological criteria selected.

Gloeocantharellus lateritius and Lentinellus pseudobarbatus, previously known only from their type specimens, are described, illustrated and discussed based on fresh collections made in southern India.

Barley plants experimentally infected with Erysiphe graminis f. sp. hordei were subjected to a curative treatment with tetraconazole (TC), to find out if the thickenings induced by the treatment in the fungal and host cell walls might be related to an increased production of chitosan. The presence of chitosan was assessed by colorimetric method, histological staining and ultrastructural localization with chitosanase bound to colloidal gold. The results showed that after TC treatment the amount of chitosan increase in the cell walls of hyphae and haustoria, and also in the haustorial encasements.

Variation in Gremmeniella abietina var. abietina was studied in three stands of Scots pine in northern Finland and in the Kola Peninsula. Eighty-four isolates of large- and small-tree types of G. abietina var. abietina (LTT and STT, respectively) were identified on the basis of tentative characteristics (spore morphology, disease type and host size), fatty acid and sterol profiles (FAST), and random amplified microsatellite technique (RAMS). Both LTT and STT occurred in all three stands. In general, the classifications obtained using the three methods agreed with one another, although a few contradicting results were observed. Variation in fatty acids and sterols in G. abietina var. abietina was rather low, although the amounts of some individual extractives showed statistically significant differences between the stands. All pathogenic and asymptotic G. abietina var. abietina isolates originating from branches located at heights above the annual snow cover were identified as LTT based on RAMS, but some were grouped to STT according to their FAST profiles. Both STT and LTT were detected among the isolates obtained from seedlings according to both FAST and RAMS. In addition, in two cases RAMS markers thought to be STT- or LTT-specific were found in the same isolate. The results presented here suggest that LTT of G. abietina var. abietina caused the devastating epidemics on pines in the first-thinning stage or middle age similar to pines in this study reported in northern Finland and in the Kola Peninsula during the 1980s.

Seventeen species of Rickia are reported from Sulawesi. Five are described: R. corylophidorum, R. mammillata, R. pocadii, R. serrulata, and R. sphindidorum. The slime mould feeding beetle family Sphindidae is reported for the first time as host for a species of the Laboulbeniales and R. minuta is recorded for the first time from a beetle, this species previously being known to parasitize only mites. For each of the reported species a detailed description with information on the known geographical distribution and host range is presented along with illustrations and a key to identification.

Nine species of Trametes and five other wood inhabiting basidiomycetes, were collected from the indigenous forests of Zimbabwe and analysed for cellulases, ligninases, extracellular phenolases and wood degrading ability for the first time. Cellulase enzyme activities varied widely among the species. After 15 d growth exo-glucanase activity had increased in the majority of species whilst filter paper activity showed the opposite trend, being greatly reduced in all species on day 15 compared to day 10. Endo-glucanase activity was relatively uniform at both sampling times. The fungi were more active against water soluble cellulose derivatives than filter paper cellulase. In all the fungi tested, cellulose activity on filter paper was significantly less than endo- and exo-glucanase activities. The highest cellulase activity was expressed by Cerrena meyenii (683 U mg−1) Phaeotrametes decipiens, Trametes modesta, and T. pocas also expressed relatively high cellulase activity on all types of cellulose tested. All Trametes species tested positive for extracellular phenol oxidases whilst Fomotopsis spragueii and Irpex stereoides tested negative. All but one of the Trametes species in the study were able to degrade two different lignin preparations in tests for lignin degradation. T. menziesii was unable to degrade both lignin preparations although it had tested positive for production of extracellular oxidase. The species in this study degraded hardwood to a greater extent than softwood. Eight of them caused more than 80% dry weight loss of wood blocks during 70 d incubation. Those fungi that expressed high cellulase activity also caused high weight loss on wood.

Cultures derived from ascospores of an Orbilia, described as a new species, O. fimicoloides, from small mammal droppings, developed conidia of Dactylella cf. oxyspora. This connection is discussed in relation to the anamorph–teleomorph connections of nematophagous fungi classified in the anamorph genera Arthrobotrys and Dactylella.

Inocybe inexpectata sp. nov., from Spain, is described and illustrated. It is characterized by its small size, brown–argillaceous tinges, strongly decurrent gills, absence of metuloid cystidia, cylindrical to suballantoid spores and a well-developed trichoderm.

Concentrations of potassium nitrate, potassium phosphate, or calcium chloride were varied in stream-simulating microcosms containing leaf discs colonized by the aquatic hyphomycetes Anguillospora filiformis or Lunulospora curvula. Cumulative conidium production of the fungi determined from rates of sporulation at 2 d intervals was stimulated by increasing concentrations of both potassium nitrate and potassium phosphate but not by calcium chloride. Leaf weight loss was also stimulated by increasing concentrations of potassium nitrate and potassium phosphate. The amount of fungal biomass (determined as ATP concentrations) associated with leaf discs increased significantly only in the treatments in which A. filiformis received increasing concentrations of potassium nitrate. These results indicate that as aquatic hyphomycetes grow on leaf litter, they can obtain at least a portion of their inorganic nutrition from the water flowing over the leaves. They also suggest that sporulation is more sensitive to changes in nutrient concentrations than growth.

In situ gene amplification (in situ PCR) is a recent, powerful molecular technique which allows the localization of low abundance nucleic acids targets directly within tissue sections. The work presented here is, to our knowledge, the first report of successful direct detection of in situ PCR amplification with fluorescently-labelled primers, and the first successful in situ PCR performed on arbuscular mycorrhizal (AM) fungi. Ribosomal SSU genes within AM fungal spore sections were amplified by using fluorescent, glomalean-specific primers, then directly detected by means of epifluorescence microscopy. Different controls confirmed the successfulness of the in situ amplification. These results open new avenues in the study of arbuscular mycorrhizas, where genetic processes seem to be transient and very localized.

Eudarluca caricis, the teleomorph of Sphaerellopsis filum, was found on blackberry rust (Phragmidium violaceum) in south west England and its morphology is described. Cultures derived from ascospores produced pycnidial conidiomata and conidia typical of S. filum, confirming the connection between the meiotic and mitotic stages of the fungus. Microconidia were also found in the cultures derived from ascospores. Conidiomata developed on the majority of uredinial pustules of P. violaceum 10 d after inoculating detached, uredinia-bearing blackberry leaves with the conidia from the cultures derived from ascospores.

Three new species of Corynespora: C. morindae-tinctoriae, C. nana and C. rosacearum on Morinda tinctoria, Lantana indica and Eriobotrya japonica respectively, are described and illustrated from Gorakhpur (U.P.) India.

Olpidium paradoxum sp. nov. was found to attack adult loricate rotifers and their eggs in a sample of pond water in Japan. The fungus produced zoosporangia inside the host from which exit tubes of variable length grew to the outside environment. Pyriform zoospores with a single long posterior flagellum were released from the sporangia.

To identify Stagonospora avenae genetically, 53 isolates from Europe and North America were assessed by RFLP analysis and internal transcribed spacer (ITS) sequence polymorphisms in comparison with isolates of S. nodorum, S. arenaria and Septoria tritici. Our results also provided insight on possible phylogenetic divergence within the species currently identified by characteristic conidial morphology as S. avenae. Isolates from Europe, Canada, Minnesota and North Dakota showed little genetic variation. In RFLP and ITS sequence analyses, S. avenae isolates from New York and ATCC 12277 (origin unknown) had a closer relationship with barley-biotype S. nodorum, and S. avenae f. sp. triticea isolates of ATCC 26370 and ATCC 26377 from Minnesota were closely associated with wheat-biotype S. nodorum. Enzyme restrictions of ITS PCR-amplified products could facilitate the identification of Stagonospora on cereals.

Chlorotic leaf distortion (CLD) is an unusual disorder of sweet potato caused by a morphologically unique strain of Fusarium lateritium. This study compared 15 isolates of F. lateritium from sweet potato with nine isolates from other hosts for genetic diversity by RAPD analysis and RFLP analysis of the intergenic spacer region and the ITS region of the rDNA. In RAPD analysis, 12 of the sweet potato isolates clustered very closely, nine with similarity of >0·99, and three additional isolates at a similarity of >0·86. This group comprised two pathotypes and included isolates from U.S.A., South America, Asia and Africa. The remaining isolates, comprising three from sweet potato and all isolates from other hosts, showed little similarity with the cluster of sweet potato isolates. RFLP analysis produced similar results, with the 12 isolates that were clustered in RAPD analysis and one additional sweet potato isolate clustered at >0·80 similarity. These data suggest that the sweet potato CLD pathogen is relatively homogeneous and genetically distinct from other strains of F. lateritium. There was relatively little similarity among isolates of F. lateritium from other hosts.

Primary colonization and the early growth of the mycelium of Agaricus bisporus in compost could be improved to increase the rate of substrate utilization. The production of enzyme activities during the vegetative growth of a commercial strain in compost were determined. N-acetyl-glucosaminidase activity peaked during the first week whereas the activities of polysaccharidases decreased with the replacement of autochthonous micro-organisms by A. bisporus. A low level of water soluble sugars was maintained in compost inoculated with A. bisporus in comparison with a non-inoculated compost. Microbial residues and hemicelluloses appeared to be important nutrient sources during the early growth.

Results of an investigation into the fungi associated with submerged wood in Lake Barrine, north Queensland, Australia are reported. Thirty-nine fungi were identified, 15 ascomycetes, 23 deuteromycetes and one basidiomycete. The frequency of occurrence and the effect of the incubation period on the recovery of fungi has also been investigated and is presented. The new species Massarina lunispora and Dactylaria lakebarrinensis, and some other notable species, are described and illustrated.