Articles containing the keyword 'spreading'

An attempt was made to restrict the aerial distribution of Fomes annosus (now Heterobasidion annosum) through the cut surfaces of spruce stumps by inoculating the surfaces, immediately after felling, with mycelial suspension, grown in the laboratory on malt agar, of Fomes pinicola, Lenzites sepiaria, Peniophora gigantea (now Phlebiopsis gigantea), Polyporus abietinus and Trichoderma viride. Trees were felled once a month for a year. Samples were taken from the cut surfaces of the stumps approximately one year after the felling and the inoculation.

P. gigantea inhibited the infection of cut stump surfaces by airborne F. annosus. P. gigantea cut down both the total number and the number of the species of fungi infecting the stump through aerial distribution. T. viride had a parallel but less marked effect. F. pinicola, L. sepiaria and P. abietinus proved to be weak colonizers of spruce stumps. When they were used to inoculate the stumps, the number of fungi infecting the cut surfaces was larger than that infecting the stumps treated with P. gigantea and T. Viride. A year after the inoculation some stumps were excavated with their roots. Fungi from the discoloured spots of wood in the stumps were cultured for identification. It was found that many different fungal species from the soil and the points of root grafting had infected the roots of the stump in the course of the year. The majority of the identified microbes were non-Basidiomycetes fungi, and bacteria.

A year after the felling and inoculation, a white mycelial sheet was seen between the wood and bark of many stumps. Several fungi, including Armillaria mellea, Trichoderma viride, Penicillium species, and Peniophora gigantea were isolated from this sheet.

The PDF includes a summary in Finnish.

• Kallio, E-mail: tk@mm.unknown

An investigation into the aerial distribution of Fomes annosus (now Heterbasidion annosum) in Finland was carried out. Prevalence of the fungus in the air was estimated from cultural counts of mycelia produced by diaspores which had fallen onto spruce discs and agar plates. The influence of climate on deposition of diaspores was determined from weather recordings.

For the main study, F. annosus diaspores collected from spruce stands in Helsinki, Anjala and Jokioinen were recorded at weekly or fortnightly intervals throughout 1968. Diaspores fell during the 24-hour periods almost continuously at all three observation sites from April to November, but the deposition was most frequent from late May to the end of October. The amounts of deposition varied greatly with the observation sites, seasons of the year, and time of the day. The fall was heaviest at Anjala and slightest at Jokioinen.

Throughout the season of deposition, more diaspores were trapped on all observation sites at night than during the day. A significant positive correlation was found between the fall of F. annosus diaspores and the air temperature. Diaspores of F. annosus were found in the forest on needles and leaves, and underneath the humus layer in mineral soil. The fall of diaspores decreased as the distance from sporophores increased.

The aerial distribution of two antagonists to F. annosus, viz. Peniophora gigantea and Trichoderma viride, was also studied. It was found that the diaspores of the former fell mainly during the same seasons as those of F. annosus.

• Kallio, E-mail: tk@mm.unknown