Permanence of free water on coffee leaves :
The presence of free water on both surfaces of the leaves of shaded and unshaded coffee trees (cv. Colombia) was evaluated at Chinchiná, Colombia where the average annual rainfall is 2530 mm. Rainfall was the main source of humidity and dew was not registered during the experiment (7 Feb-27 April 1984). Five mm of rain caused canopy saturation and water began to reach the underside of the leaves. The period of wetness lasted 9.7 h on average and no significant moisture differences were found between leaves on east or west facing branches, at different levels within the tree, or externally or internally positioned on the branches, either for exposed or shaded trees. Between 1700 and 0500 h (local time), a close relationship was found between the time of rain initiation and the duration of the period of wetness. Leaves had dried out by about 1000 h. These findings provide a reasonable guide to the number of hours with adequate humidity for coffee leaf rust (Hemileia vastatrix) spore germination under field conditions as a function of the initial onset of rain
| Main Authors: | , |
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| Format: | biblioteca |
| Language: | eng |
| Published: |
1987
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| Subjects: | COFFEA ARABICA, HOJAS, AGUA, SUPERFICIE FOLIAR, GERMINACION, ESPORAS, CONTENIDO DE HUMEDAD, COLOMBIA, HEMILEIA VASTATRIX, |
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