Stem End Rind Breakdown Of Citrus Fruit A New Postharvest Physiological Disorder Of Lemon Fruit In Tucuman (Argentina)

Abstract

Lemon from packinghouses destined for exportation of the seasons 2008 to 2012 were surveyed. Fruits of lemon from Santa Lucia and Yacuchina (Monteros–Tucuman) exhibited unusual symptoms consisting in sunken brown spot around the stem of rind and later became dark during the packing process. The objective of this work was to determine the causal factor of these alterations. Affected tissue were collected and streaked onto PDA to identify possible causal pathogen agents. Meteorological data were analyzed from 2008 to 2012 of study area. No pathogen was isolated. Rain and relative humidity during the months previous to harvest (March to April) were lower, and temperature higher than the average values over the last 45 years. Based on symptoms and antecedent of other citric areas of the world a physiological disorder stem end rind breakdown of citrus (SERB) was determined. This disorder was found in thin-skinned fruit from humid, high rainfall areas and water stressed trees. Collapse of the rind tissue, and not discolored around the button (thick layer of natural wax of cuticle) were the first symptoms observed. Subsequently, the oil glands collapsed followed by a discoloration of the collapsed area. Postharvest management that reduced fruit desiccation lessens incidence and severity of SERB.