Articles
LEAF MG SPRAYS REDUCE LEAF CHLOROSIS AND NECROSIS SYMPTOMS IN APPLE TREES ‘NICOTER’
Article number
984_41
Pages
339 – 346
Language
English
Abstract
Apple cultivar Nicoter fruits have been appreciated by consumers, which are commercialized under the brand Kanzi®, through a so called Club system.
In Italy, as well as in other countries, young plantings of this cultivar often show leaf necrosis in summer as well as early drop of basal and median leaves, a phenomenon that may depress tree productivity as well as fruit quality.
We have investigated the role of magnesium (Mg) in this syndrome by applying Mg (and in one orchard also manganese – Mn) salts in contrasting periods of the season to the tree canopy, or to soil, in two orchards located in South Tyrol (Italy) where trees previously showed leaf necrosis symptoms.
The experiments were carried out in 2008 and 2009. Contrasting to the Mn sprays and soil Mg supply, the Mg foliar sprays have severely reduced the number of leaves affected by necrosis as well as the degree of severity of the symp¬toms, also enhancing the Mg concentration of leaves.
Unsprayed, control trees often had leaf Mg concentration below 0.15%, while leaves with severe necrosis symptoms had an average Mg concentration of 0.08%. We concluded that temporary Mg deficiency of old leaves is responsible for leaf necrosis and early leaf drop in trees of Nicoter. Leaf spray of Mg salt is effective in reducing the symptom intensity.
In Italy, as well as in other countries, young plantings of this cultivar often show leaf necrosis in summer as well as early drop of basal and median leaves, a phenomenon that may depress tree productivity as well as fruit quality.
We have investigated the role of magnesium (Mg) in this syndrome by applying Mg (and in one orchard also manganese – Mn) salts in contrasting periods of the season to the tree canopy, or to soil, in two orchards located in South Tyrol (Italy) where trees previously showed leaf necrosis symptoms.
The experiments were carried out in 2008 and 2009. Contrasting to the Mn sprays and soil Mg supply, the Mg foliar sprays have severely reduced the number of leaves affected by necrosis as well as the degree of severity of the symp¬toms, also enhancing the Mg concentration of leaves.
Unsprayed, control trees often had leaf Mg concentration below 0.15%, while leaves with severe necrosis symptoms had an average Mg concentration of 0.08%. We concluded that temporary Mg deficiency of old leaves is responsible for leaf necrosis and early leaf drop in trees of Nicoter. Leaf spray of Mg salt is effective in reducing the symptom intensity.
Authors
D. Zanotelli, M. Rechenmacher, M. Tagliavini, W. Guerra, A. Cassar, R. Stainer
Keywords
deficiency, foliar sprays, leaf necrosis, magnesium
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