The Effects of Fog Moisture Treatment on Reduction of Water Core Occurrence in Apple

The objective of this study was to examine the efficiency of fog system for decrease of water core, one of the physiological disorders, in fruits of apple cultivar 'Hongro'. Recently, global warming occurs abnormally high temperature in summer and it induces water core to increase in fruits. Therefore, we introduced a fog system to reduce temperature by exchange of heat energy, which decreases water core incidence. We performed field experiments at 9 orchards during the end of June to August in 2012. We tested 6-year-old+ 'Hongro' trees and the elevation of the orchards was 126 to 306 m. The fog system was sprinkled on at 3.5 L per a tree for half an hour twice at 6:00 and 8:00 p.m. when air temperature is over 28±1 °C at 6:00 p.m. The temperature of fruits and trunks showed higher than that of foliage. The fog system was sprinkled on average of 25 times during the experiment period. Temperature at the sprinkled by the fog system was lower 0.5 °C than that of control, regardless of the orchard environment. Fruit characteristics, such as weight, sugar degree, and acid content, were no different between treatments. However, severity of water core with fog system was reduced to average 22.7% and showed high significance between treatments and among orchards. In conclusion, the preceding results showed the possibility that the sprinkling of fog system reduces water core by exchanging heat energy in tree.