Some Aspects of the Relationship between Shade and Fungal Pathogenicity in an Epidemic Disease of Pines
Some of the environmental factors predisposing Corsican Pine to an epidemic disease known as dieback were studied. The disease is most prevalent on north-facing slopes, while south-facing slopes are normally unaffected. Trees on north-facing slopes produce poor height growth and those showing the po...
| Veröffentlicht in: | New Phytologist. - New Phytologist Trust. - 67(1968), 1, Seite 39-48 |
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| 1. Verfasser: | |
| Format: | Online-Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
1968
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| Zugriff auf das übergeordnete Werk: | New Phytologist |
| Schlagworte: | Biological sciences Health sciences Physical sciences |
| Zusammenfassung: | Some of the environmental factors predisposing Corsican Pine to an epidemic disease known as dieback were studied. The disease is most prevalent on north-facing slopes, while south-facing slopes are normally unaffected. Trees on north-facing slopes produce poor height growth and those showing the poorest growth eventually succumb to the disease. A characteristic feature of the diseased slopes is the absence of sunlight in winter. Disease symptoms appear in this period of sun shadow. The effect of shade on disease susceptibility was therefore investigated. Large increases of infection by Brunchorstia pinea were found after 2, 4, 8 and 12 weeks artifical shading. Artificial shading caused reduction of the soluble carbohydrate content of the buds. Disease-susceptible buds on north-facing slopes had comparable low carbohydrate contents, while the levels in resistant buds on south aspects were significantly greater. Soluble carbohydrate content at the end of the growing season was found to be similar in both aspects, but there was a steady decrease through the winter on the north-facing slope until by January the content was considerably lower than that on the south aspect. Dieback is therefore believed to be caused by fungal attack following loss of respiratory substrate during a prolonged period of low light intensity. Factors such as low growing season temperature and high humidities play a subsidiary role by reducing host vigour and increasing the fungal population. |
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| ISSN: | 14698137 |