treated trees became so susceptible to colonisation by H. annosum is not clear.
Growth of Heterobasidion annosum in Sitka spruce bark: influence on position and chemistry of the ligno-suberized boundary zone.
BECKETT, E., BODLES, W.J.A. & WOODWARD, S. University of Aberdeen, School of Biological Sciences, Hilton Campus, Hilton Avenue, Aberdeen AB24 4FA, Scotland, UK
The effects of inoculation with Heterobasidion annosum on wound boundary zone formation and traumatic resin duct production was assessed using a combination of light, epifluorescence and fourier-transformed infra-red (FTIR) microscopy. Lignification and suberization occurs at the boundary zone to form the LSZ, which prevents desiccation and further pathogen infection. Different genetic types of Sitka spruce were wounded and/or inoculated with H. annosum and the temporal and spatial development of the LSZ was quantified. Initial results show that less susceptible genotypes respond with thicker lignified layers. No differences in traumatic resin canal formation were observed in wounded or wounded and inoculated plants. FTIR microscopy suggested that lignin and suberin chemistry differed in bark of plants (a) inoculated with the pathogen, compared to those that were wounded only, and (b) between clones of Sitka spruce forming long or short bark lesions following inoculation.
Modelling Heterobasidion annosum: validating MOHIEF with real-time data from a species-susceptibility trial in Britain.
MOSELEY, D.1, PRATT, J.2, PUKKALA, T.3, THORPE, K.4, TRACEY, D.5, WOODWARD, S.1.
1: University of Aberdeen, School of Biological Sciences, Hilton Campus, Hilton Avenue, Aberdeen AB24 4FA, Scotland, UK, 2: Forest Research, Roslin, Midlothian EH25 9SY, Scotland, UK., 3: University of Joensuu, Faculty of Forestry, Joensuu, FIN-80101, Finland. 4: Forest Research, Alice Holt Lodge, Farnham, Surrey GU10 4LH, UK.5: Forest Research, Forestry Commission, Lochgilphead, Argyll, Scotland, UK.
Data on infection of 10 species of conifer and the estimated frequency of inoculum sources (stumps) present, collected from a third-rotation site at Lael forest, NW Britain were used to validate part of a Europe-based model of Heterobasidion annosum known as MOHIEF (Modelling of Heterobasidion in European Forests). The model was used to derive infection rates for standing trees, across the range of species, by varying the probability of disease transfer from stump to tree (P[S-T]), in an effort to replicate the range of infection measured in the field trial. Values of (P:S-T) were then used to estimate long-term disease development in successor crops. The results indicated that the optimum treatment for this site would be to replace the existing crop with oak, a Heterobasidion resistant species, using Scots pine as a nurse species.
Pathogenicity of Rhizoctonia solani isolates of different anastomosis groups to Scots pine seedlings
Sylwia Stępniewska and Małgorzata Mańka,
Department of Forest Pathology, The August Cieszkowski Agricultural University, ul. Wojska Polskiego 71c, 60-625 Poznań, Poland, fax 004861/848-77-11, e-mail:
Thirty eight isolates of Rhizoctonia spp. were obtained from Scots pine (Pinus sylvestris L.) seedlings with damping-off symptoms, from two forest nurseries in Wielkopolska region in central-west Poland (Wronczyn and Jarocin). The majority of the isolates (79%) had multinucleate cells and were identified as Rhizoctonia solani Kühn. The remaining isolates were recognized as binucleate Rhizoctonia spp. Rhizoctonia solani isolates were characterized using hyphal anastomosis and divided into 5 anastomosis groups (AGs). The most prevalent one was AG5 (37% of isolates), 30% belonged to AG2-1 and 27% of isolates were identified as AG4. Groups AG1-IB and AG2-2 were represented by single isolates. Their pathogenicity to Scots pine seedlings in tests on Petri dishes was comparatively high for R. solani isolates from all AGs. Variation in seedling mortality levels was not influenced by the origin of the isolates, either. Within 7 days post inoculation most of isolates were highly pathogenic to pine seedlings. The average seedlings’ mortality ranged from 0% for 3 isolates to 100% for 8 isolates.
Study of endophytic mycobiota of selected fruit trees with special reference to genus Pezicula (including Neofabrae) in the Czech Republic - a preliminary results
David Novotný Department of Mycology, Division of Plant Medicine, Research Institute of Crop Production, Drnovska 507, 161 06 Praha 6 – Ruzyne, Czech Republic, email: email@example.com
Trees harbour many species of asymptomatically living endophytic fungi which can be potentially plant pathogen. Endophytic communities are often specific at the host species, organ and tissue level. So far, little attention has been paid to composition of endophytic mycobiota of fruit trees. Neofabraea alba, N. malicorticis and Glomerella cingulata are known as a pathogens of apple and pear trees, but can be probably plant endophyte. According EPPO standards certification schemes apple and pear candidate nuclear stock should be free from these fungal species. The aim of present study is recognize composition of endophytic mycobiota of selected parts of apple and pear trees (Malus domesticus and Pyrus communis). The special attention is focused to occurrence Neofabraea alba, N. malicorticis and Glomerella cingulata (anamorph Colletotrichum gloeosporioides) in apple and pear trees in the Czech Republic. The present study started in spring 2004 and