To provide some guidelines for minimizing cold injury in fruit trees, a survey was made to investigate the cold injury caused by the severe weather of 1980∼1981 in the mid-inland region. Summarized results are as follows:
1. Severe cold weather during the winter months of 1980∼1981 caused a serious injury on tree trunks, branching positions of main branches, and flower and leaf buds in fruit trees, resulting in partial or total winter killing. The percentage of fruit trees in Gyeonggi province in which 30% or more trees showed apparent cold injury was 50.2% for peaches, 19.8% for grapes, 7.6% for pears, and 2.4% for apples, respectively.
2. Regardless of the difference in fruit species, older trees showed weaker cold hardiness than younger trees. Severe cold injury was observed in peach trees planted in plain lands as compared to those in hilly sites.
3. Cold hardiness varied greatly depending upon the cultivars. The average percentages of cold injury in apple cultivars were 22.9% in Mutsu, 10.4% in Tsugaru and 6.7% in Golden Delicious, respectively. Fuji and Spur EarliBlaze showed only a slight injury.
4. Cold injury was sharply increased when the temperature dropped below - 18℃ for peaches, -21 to -25℃ for grapes and pears. In apples, however, the cold injury was slight even at -32.6℃ and no significant correlation was found between the recorded temperatures and the degree of cold injury.
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