Cladochytrium salsuginosum sp. nov. — a new zoosporic fungus from Poland

<i>Cladochytrium salsuginosum</i> sp. nov. isolated from braskish water of the Baltic bay Zalew Wiślany in Poland on onion skin bails is described. The new species is allied to the american <i>C. crassum</i> Hillegas but differs in many morphological features.

Zoosporic fungi in springs in the vicinity of Białystok

Zoosporic fungi and environmental factors in 5 springs were analysed at monthly intervals for one year. A total of 83 zoosporic fungus species were noted. 13 species are new to the hydromycoflora of Poland.

Zoosporic fungi in the ice of some water reservoirs

The presence of 65 zoosporic fungi species was noted in the water obtained from melting ice from five water (3 ponds and 2 rivers). In the water of the all basins the number of zoosporic fungus species decreases along with the increasing chemical loading (more eutrophic water). Out of these 65 species, 18 are known as necrotrophs of fish. The following fungi were recorded for the first time from Poland: <em>Achlya conspicua</em>, <em>Apodachlyella completa</em>, <em>Pythiomorpha undulata</em>, <em>Pythium butleri</em>, <em>Pythium carolinianum</em>, <em>Pythium gracile</em>, <em>Pythium imperfectum</em>, <em>Pythium indicum</em>, <em>Pythium irregulare</em>, <em>Pythium myriotylum</em>, <em>Pythium papillatum</em>, <em>Pythium pyrilobum</em> and <em>Pythium rostratum</em>.

Olpidium bornovanus-Mediated Germination of Ascospores of Monosporascus cannonballus: A Host-Specific Rhizosphere Interaction

Monosporascus cannonballus, a host-specific root-infecting ascomycete, is the causal agent of a destructive disease of melon (Cucumis melo L.) known as vine decline. Ascospores germinate only in the rhizosphere of melon plants growing in field soil. However, no germination occurs in the rhizosphere of melon plants if the field soil is heated to temperatures >50°C prior to infestation with ascospores. This observation suggested that germination is mediated by one or more heat-sensitive members of the soil microflora. Although bacteria or actinomycetes were heretofore suspected as the germination-inducing microbes, our data demonstrate that Olpidium bornovanus, an obligate, host-specific, root-infecting zoosporic fungus, is responsible. In four experiments conducted in autoclaved field soil amended with various population densities of culturally produced ascospores, significant ascospore germination was recorded only in the rhizosphere of cantaloupe seedlings colonized by O. bornovanus.

Pathogenicity and Management of Olpidium bornovanus, a Root Pathogen of Melons

Greenhouse studies document, for the first time, that Olpidium bornovanus, an obligate, holocarpic, root-inhabiting zoosporic fungus heretofore regarded as a nonpathogenic parasite, is a root pathogen. Significant browning of the roots and reductions in shoot and root growth were recorded within 28 days following inoculation of melons with the fungus. Amending the recirculating nutrient solution with either a nonionic surfactant (Agral 90) or a strobilurin fungicide (azoxystrobin) resulted in efficacious management of the disease caused by the fungus.

Aquatic fungi growing on the spawn of certain amphibians

The mycoflora developing on the spawn of nine species of amphibians was investigated under laboratory conditions. Fifty-two zoosporic fungus species were found to grow on the spawn investigated, including 6 chytridiomycetes, 1 hyphochytriomycete, 44 oomycetes and 1 zygomycete fungus. Out of these 52 species, 23 are known as parasites or necrotrophs of fish. Five fungus species were recorded for the first time from Poland.

Morphology and zoospore ultrastructure of Lacustromyces hiemalis gen. et sp.nov. (Chytridiales)

As part of a baseline study of chytridiomycete fungi in two Maine lakes, a polycentric, chitinophilic, and heretofore undescribed zoosporic fungus was found. The tubular thallus of Lacustromyces hiemalis gen. et sp.nov. has intercalary thin-walled zoosporangia, has thick-walled resistant sporangia, and does not grow at temperatures greater than 23 °C. Transmission electron microscopy revealed that its zoospores are a variant of the chytridialean type. The microbody – lipid globule complex is of a previously undescribed type, lacking a rumposome or other membrane cisterna and consisting of multiple lipid globules enclosed in a microbody that extends towards the kinetosome. Three kinds of microtubule roots arise near the kinetosome, a root leading to the microbody, a ribosomal root, and a microtubule organizing center that gives rise to microtubules that extend singly into the cytoplasm. Key words: Chytridiales, fungus, Lacustromyces, lake, ultrastructure, zoospore.