Reducing russeting of Golden Group Apple Cultivars organically grown with Potassium Bicarbonate

Abstract

One of the biggest problems for organic apple growing is the quality of fruits that means size, color, and shape characteristic to the cultivar, without russeting. The fruits are very sensitive six weeks after bloom (Gildemacher, 2000). Sensitivity to russeting can be built in the period before bloom (Babin, 1977, Berkett, 2005. The effects are more visible when the cooper based fungicides before bloom are used. When the copper was replaced with sulphur or lime sulfur, better results were obtained (Jong, 2008). Experiments were conducted in 2008 in a commercial orchard at SC Agroindustriala SA ClujNapoca. The former is 5 ha of five years old trees on M9 spaced at 3,5 X 0,9 m including five cultivars of Golden Group: Golden Delicious, Golden Reinders, Lysgolden, Smoothee. The objective of this study was to test the effect of potassium bicarbonate in reducing apple russeting in comparison with classical product used in organically apple grown The experimental applied products were: copper hidroxid, 50%, wettable sulphur 80%, potassium bicarbonate 20% . Best results in reducing russeting to Golden Group were obtained in variants treated with potassium bicarbonate, where values obtained were ranged in scale between light and moderate russet, with differences statistically insured against variants treated with copper hydroxid. Treatment with wettable sulphur were less indus russeting than those with copper hydroxid.