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Features of Hymenoscyphus fraxineus fruiting
in forests of Minsk Upland and Central forest-steppe Storozhenko V.G.1, Baranchikov Y.N.2, Seraya L.G.3, Chebotareva V.V.4, Chebotarev P.A.4, Yaruk A.V.5, Zviagintsev V.B.5
Hymenoscyphus fraxineus (T. Kowalski) Baral, Queloz, Hosoya is a
pathogenic ascomycete, the causative agent of infectious necrosis of ash
branches (pic.1), that leads to mass drying of ash trees all over the
Europe. Penetration of the pathogen into the host plant occurs through
the leaf plate, then the infection spreads through the petiole and is
transmitted to the shoots. After the foliage falls, a black pseudosclerotic
plate is formed on the surface of the affected petioles and then apothecia
are subsequently formed on it. The spread of infection occurs in the
summer with the help of wind-transported ascospores. Despite the wide
prevalence of the disease in the stands of Belarus and Russia, the
quantitative characteristics of H. fraxineus sexual sporulation have not
been reported in the literature yet.
The aim of our work was to study the features of fruiting of the fungus
in forests of Minsk Upland and Central forest-steppe.
1. Introduction
4. Discussion
It is revealed that the pathogen is able to massively form sexual
reproduction organs in a new area (Russia), but the intensity of fruiting in
the conditions of Belarus is much higher due to a much longer period of its
accumulation. The formation of apotecia correlates with the hydrogen
index in the warm period of the year, which form the level of the infectious
background. The absence of a black pseudosclerotic plate on the surface of
the petioles does not evidence of uncontaminating with pathogen. The
presence of this modification of the mycelium is not necessary for the
fruiting of this fungus.
5. References
Kowalski, T. Chalara fraxinea sp. nov. associated with dieback of ash (Fraxinus excelsior) in Poland / T. Kowalski // Forest Pathology. – 2006.
– Vol. 36. – Р. 264.
Schumacher, J. First record of Chalara fraxinea T. Kowalski sp. nov. in Germany – a new agent of ash decline / J. Schumacher, A. Wulf, S.
Leonhard // Nachrichtenbl. Deut. Pflanzenschutzd. – 2007. – Vol. 59. – P. 121–123.
Halmschlager, E. First report of the ash dieback pathogen Chalara fraxinea on Fraxinus excelsior in Austria / E. Halmschlager, T. Kirisits //
Plant Pathology. – 2008. – Vol. 57. – №. 6. – P. 1177–1177.
Gross, A. On the longevity of Hymenoscyphus pseudoalbidus in petioles of Fraxinus excelsior / A. Gross, O. Holdenrieder // Forest Pathology.
– 2013. – Vol. 43. – №. 2. – P. 168–170.
Kirisits, T. The current situation of ash dieback caused by Chalara fraxinea in Austria / T. Kirisits [et al.] // Proceedings of the conference of
IUFRO working party. – 2009. – Vol. 7. – №. 2. – P. 97–119.
Kowalski, T. The teleomorph of Chalara fraxinea, the causal agent of ash dieback / T. Kowalski, O. Holdenrieder // Forest Pathology. – 2009. –
Vol. 39. – №. 5. – P. 304–308.
Timmermann, V. Ash dieback: pathogen spread and diurnal patterns of ascospore dispersal, with special emphasis on Norway / V. Timmermann
[et al.] // EPPO Bulletin. – 2011. – Vol. 41. – №. 1. – P. 14–20.
Yaruk, A.V. and Zviagintsev, V.B. 2015. Ярук, А. В. Звягинцев, В. Б. Распространённость халарового некроза в насаждениях и посадках
ясеня обыкновенного [Occurrence of ash dieback in stands and plantings of European ash]. Proceedings of the Belorussian State
Technological University, series Forestry 174: 207-210.
Musolin D.L., Selikhovkin A.V. Shabunin D.A., ZviagintsevV.B. and Baranchikov Y.N. Between Ash Dieback and Emerald Ash Borer: Two
Asian Invaders in Russia and Future of Ashes in Europe (в печати).
Dvorak M., Rotkova G., Botella L. Detection of airborne inoculum of Hymenoscyphus fraxineus and H. albidus during seasonal fluctuations
associated with absence of apothecia //Forests. – 2015. – Vol. 7. – №. 1. – P. 1.
2. Method and experimental approach
In 2016 we set up registration areas in ash stands in the Negorelloe educational and
experimental forestry (Minsk Upland, Belarus) and in the Tellerman experimental
forestry (Central forest-steppe, Russia).
On sites measuring 1x1 m, the number of ash petioles in a leaf drop was recorded. While
accounting the petioles differentiated by the presence of the pseudosclerotic plate (black
color), its partial formation or without signs of a pseudosclerotic plate (light color). The
presence of fruiting bodies of H. fraxineus on the petioles and the correlation of the
petioles color with the formation of the apotecia of the pathogen were analyzed.
Confirmation of belonging sporocarps to species was selectively performed by PCR
analysis.
3. Results
On the fallen petioles of the ash in the litter, the abundant fruiting of the fungus H. fraxineus was revealed at all observation sites. Fruit bodies from
different regions had similar morphology and sizes, the color varied from white to brown depending on the age of apotecia (pic. 3). The period of
maximum fruiting in the Tellerman forestry was observed in early July, the percentage of petioles with developed fruiting bodies was 21.8%. In
Belarus, the peak of fruiting was observed at the end of the second decade of July and the number of petioles with fruiting bodies was 93.4% (pic. 4).
The distribution of apotecia formation is closely related to the dynamics of hydrothermal index, which confirms the possibility of predicting the
intensity of spread and development of the disease during the growing season. However, the relationship between the coloring of leaf petioles and
the presence of pathogenic fungus on them was not observed - apothecia formed both on completely dark and partially colored or light petioles.
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1. Institute of Forest Scienсe, Russian Academy of Scienсes, Russia, [email protected]
2. Department of Forest Zoology, V.N. Sukachev Institute of Forest, Russia, [email protected]
3. The Tsytsin Main Moscow Botanical Garden of Academy of Sciences, Moscow, Russia [email protected]
4. Tellerman Experimental Forestry of the Institute of Forestry of the Russian Academy of Sciences, Russia
5. Belarussian State Technological University, Minsk, Belarus, [email protected], [email protected]
Picture 1. The symptoms of ash dieback
Picture 2. Ash petioles with black pseudosclerotic
plate (a) and with its partial formation (b)
(Tellerman experimental forestry , 2016)
b
a
Picture 3. Ash petioles with apotecia (a) Minsk Upland, Belarus (b) Central forest-
steppe, Russia (2016) Picture 4. Dynamics of apotecia formation and
hydrothermal index (Minsk Upland, Belarus, 2016)
