• The Bimonthly Magazine for Agrochemicals and Plant Protection
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• v.1 no.8
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• pp.64-68
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• 1980

• The Science & Technology
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• v.14 no.7 s.146
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• pp.56-57
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• 1981

• The Bimonthly Magazine for Agrochemicals and Plant Protection
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• v.3 no.3
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• pp.73-78
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• 1982

• The Bimonthly Magazine for Agrochemicals and Plant Protection
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• v.13 no.2 s.107
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• pp.48-55
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• 1992

• Research in Plant Disease
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• v.22 no.3
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• pp.198-201
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• 2016

Recently, severe dieback of apple tree has occurred in the apple orchards of Chungbuk province. Dieback rate and its casual agents have been investigated on the Chungbuk province apple orchards in 2013-2015. Out of 29,265 apple trees in the 27 orchards throughout Chungbuk province, 4,000 apple trees (13.7%) showed dieback symptoms. The causes of dieback were Phytophthora rot (50.4%), violet root rot by Helicobasidium sp. (27.1%), rodents (10%), white root rot by Rosellinia sp. (6.3%), and freezing injury (6.3%). Compared to previous reports published in 1995 and 2006, Phytophthora rot was the most dominant disease, which is thought to be due to high temperature during growing season and the increase of lowland cultivation. Results of this study will be useful to establish of the management strategy of apple tree dieback that has been increased recently.

• The Bimonthly Magazine for Agrochemicals and Plant Protection
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• v.10 no.2 s.89
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• pp.34-43
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• 1989

• The Journal of Natural Sciences
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• v.18 no.1
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• pp.55-63
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• 2007

This research was conducted to investigate the effects of calcium solution spray on the accumulation of calcium into apple fruit. $^{45}_{CaCl_2}$ applied to fruit with different growth stages showed that more $^{45}Ca$ was penetrated into fruits when applied in the late stage than early stage. Slight radioactivity was detected only in pedicel except leaf when $^{45}Ca$ was treated on the leaves proximate to the fruit. When the Ca was treated on fruit surface only, calcium contents of fruit was increased.

• Korean journal of applied entomology
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• v.26 no.4 s.73
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• pp.245-249
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• 1987

In the 82 apple varieties tested, the distribution of varieties grouped on the damage degree to Alternaria leaf spot were 15 varieties(l8.3%), which damaged above 50%, and 51 varieties(62.2%) damaged below 5%. Susceptible varieties to Alternaria leaf spot were Raritan, Indo, Winesap and Starkrimson, moderately resistant varieties Sekaiichi and Starking, and resistant Jonathan, Tsugaru, Molliies, Jonagold, Gala etc. The leaf hair density on the backside of leaf were rarer inresistant varieties than susceptible one. In inoculation test, penetration and infection of Alternaria mali were easier on the backside than surface of apple leaf at the same varity, and infection rate with Alternaria mali were higher at removal treatment than non-removal one of leaf hairs, so we can guess that leaf hair are related to resistance of variety to Alternaria mali.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.4
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• pp.357-364
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• 1999

This study measures the influence of grass cover on water use and shoot growth of apple trees growing under different soil water regimes in temperate climate conditions and evaluates monthly crop coefficients of such conditions during four months of the growing season in 1995. To do so, double pot lysimeter experiments of 3-year-old Fuji' apple (Males domestica Borkh.) trees under a transparent rain shield were designed and installed. Trees were triplicate under three soil water regimes: (A) drip-irrigation at -50 kPa of soil matric potential (IR50). (B) drip-irrigation at -80 kPa of soil matric potential (IR80), and (C) constant shallow water table at 0.45 m below the soil surface (WT45). In each treatment, two soil surface conditions were tested: the soil surface bare, and covered with turf grasses. Mean monthly water use increased with increasing soil matric potential for drip irrigation and was greatest in the WT45 treatment. Monthly crop coefficients increased linearly in time for drip-irrigated apple trees ($r^2$ values of $0.953^{***}$ for turf grass-covered system and of $0.862^{***}$ for bare surface system), while those obtained in the WT45 treatment fluctuated, Duncan's multiple range tests for shoot growth showed that grass-covered IR50 was most favorable to apple trees. while bare surface waterlogged situation was most adverse at least in part due to a lack of oxygen in the root zone. Mid-season leaf Kjeldahl-N was higher in drip-irrigated apple trees than in WT45 trees, while soil Kjeldahl-N was not different irrespective of treatments.

• Journal of Bio-Environment Control
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• v.30 no.4
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• pp.342-350
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• 2021

This study was conducted to investigate the effect of time of hand-thinning on vegetative growth, bitter pit incidence, fruit quality, and return bloom in 'Gamhong'/M.9 apple trees. The time of hand-thinning were 3, 5, 7 and 9 weeks after full bloom, and the primary thinning (leaving only the king fruit on cluster) and secondary thinning (adjusting crop load) were conducted at the same time. The time of hand-thinning was correlated to the vegetative growth, average fruit wight, yield, soluble solids content, bitter pit incidence, and return bloom, negatively, and to the yield of middle grade fruits (fruit weight was 250-299g and none pit on fruit surface) per tree, calcium contents of leaves, and fruit red color, positively. There was no significant effect of time of hand-thinning on fruit firmness, titratable acidity, and total incomes per tree. In conclusion, if the time of hand-thinning of 'Gamhong'/M.9 apple tree was completed at 9 weeks after full bloom, it could produce about 300g of high-quality fruit without bitter pit.