Intensity of brown eye spot in young coffee plants under influence of N and K doses in nutrient solution
Intensity of brown eye spot was evaluated in young coffee plants (variety Catuai) in the presence of increasing levels of N and K. An experiment was carried with 16 treatments, 3 replicates and 2 plants per plot, using a factorial with 4 levels of N(3, 7, 11 and 15 mmol/L) combined with 4 levels of K (3, 5, 7 and 9 mmol/L) in a coffee nursery at Vicosa, MG. After 7 inoculations with suspensions of Cercospora coffeicola (15 000 conidia/mL), the total number of leaves, number of leaves with lesions, total number of lesions and the number of lesions per leaf were determined. Plants were picked and defoliation (percent), total leaf area and leaf area with lesions were determined. Then the leaves, roots and stems were placed in separate paper bags and oven-dried for 3 to 4 days at 70°C until they reached a constant weight. The N, P, S, K, Ca, Mg, Cu, Zn and Fe leaf contents were analysed. Total dry matter production, total leaf area and the area below the curve of progress for the total number of leaves were not influenced by the levels of K, but increased with increasing levels of N. There was an increase in areas below the curve of progress for the total number of lesions, number of lesions per leaf and defoliation (percent), with increasing levels of K and a reduced levels of N. There was a tendency for a reduction of leaf area with lesions (percent) with increasing levels of N and decreasing levels of K. The area below the curve of progress for the number of leaves with lesions was not influenced by the studied levels of N and K. Increasing levels of K reduced the Ca and Cu leaf contents, indicating a possible relation between their contents and the increase of disease.
| Main Authors: | , , , , |
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| Format: | biblioteca |
| Published: |
2000
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| Subjects: | COFFEA, CERCOSPORA COFFEICOLA, COBRE, DEFOLIACION, POTASIO, CALCIO, NITROGENO, NUTRIENTES MINERALES, NUTRICION DE LAS PLANTAS, ORGANISMOS PATOGENOS, ENFERMEDADES DE LAS PLANTAS, ENFERMEDADES FUNGOSAS, PLANTAS ESTIMULANTES, MINAS GERAIS, BRASIL, |
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| Summary: | Intensity of brown eye spot was evaluated in young coffee plants (variety Catuai) in the presence of increasing levels of N and K. An experiment was carried with 16 treatments, 3 replicates and 2 plants per plot, using a factorial with 4 levels of N(3, 7, 11 and 15 mmol/L) combined with 4 levels of K (3, 5, 7 and 9 mmol/L) in a coffee nursery at Vicosa, MG. After 7 inoculations with suspensions of Cercospora coffeicola (15 000 conidia/mL), the total number of leaves, number of leaves with lesions, total number of lesions and the number of lesions per leaf were determined. Plants were picked and defoliation (percent), total leaf area and leaf area with lesions were determined. Then the leaves, roots and stems were placed in separate paper bags and oven-dried for 3 to 4 days at 70°C until they reached a constant weight. The N, P, S, K, Ca, Mg, Cu, Zn and Fe leaf contents were analysed. Total dry matter production, total leaf area and the area below the curve of progress for the total number of leaves were not influenced by the levels of K, but increased with increasing levels of N. There was an increase in areas below the curve of progress for the total number of lesions, number of lesions per leaf and defoliation (percent), with increasing levels of K and a reduced levels of N. There was a tendency for a reduction of leaf area with lesions (percent) with increasing levels of N and decreasing levels of K. The area below the curve of progress for the number of leaves with lesions was not influenced by the studied levels of N and K. Increasing levels of K reduced the Ca and Cu leaf contents, indicating a possible relation between their contents and the increase of disease. |
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