Mark:                                                    GB_000002

Author(s):                                            Ligetfalusi Kovács, I.

Title:                                                     Potential biological control of Heterobasidion annosum by antagonistic Rbizobacteria on Scots pine seedlings. Part I.

Source:                                                Erdészeti és Faipari Tudományos Közlemények, Erdészeti és Faipari Egyetem Sopron ; 1994-1995. év. 40-41 évfolyam. p.: 67 - 81 Egyetemi Jegyzetsokszorosító, Sopron, 1996.

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Keywords: microbial antagonism, biological control, Heterobasidion annosum, rhizomicrobes, Scots pine, Pinus silvestris L.

SUMMARY

H.annosum could be isolated from two of the five diseased Scots pine stand on humic sandy soil. All of the stands were of first generation forests and the usual tending was carried out in them. From the two sound-looking trees found in one of the diseased stands besides H.annosum two other fungi also developed from the root-segments. According to the identification for genera one of them was a Verticillium sp. while the other Cylindrocarpon sp. From the root samples of the sound stand without any tending experimentally Chalara and Cladosporium sp. were cultured. In a separate cross plating test on malt agar these fungus could arrest the growth of H.annosum isolates. Remarkable phisiological variation was found among the different isolates with regard to the growth on different pH-values and temperature.

From the fine root system of the sound and sound-looking trees tree hundred rhizomicrobe isolates were obtained. The majority of them was bacterium but there were some actinomycetes and moulds, too among them. By the crossing plate technique twenty were screened as antagonists to the three H.annosum strains of different growth activity. It has been found that there was such bacterium in the microbial community of the root region under sound and sound-looking trees in stands sampled which could inhibit the growth of H.annosum in sterile conditions. Degree of the inhibition changed depending on the bacterial and fungal isolates tested. By the size of the inhibiting zones five bacterial isolates look promising for biopreparatum containing anatagonists. Two of them belong to the group of Bacillus megaterium sp., the third belongs to Rhizobium genus, the fourth was identified as a Pseudomonas fluorescens sp. and finally, the fifth belongs to Coryneform bacteria.