• Korean journal of applied entomology
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• v.24 no.3 s.64
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• pp.157-162
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• 1985

Leaf damage rate and actual damaged leaf area by the apple leaf miner (ALM), Phyllonorycter ringoniella(Matsumura), and its parasitism were investigated in 1982 and 1983 in apple orchards. Percent leaf damage was higher in the occasionally sprayed orchards than in the periodically sprayed orchards from May to August, but the trend was reversed after September. Seasonal changes of the leaf damage seemed to be different with the varieties of apple trees. A few species of Eulophidae and Holcothorax testaceipes R. of Encyrtidae were the predominant parasites of the ALM. Overall percent parasitism was highest in the 5th (overwintering) generation, and conspicuously decreased in the 3rd-4th generation (July-August) when insecticides were sprayed periodically. Actual damaged leaf area per mine of the ALM was apparently different with the generations; $0.67cm^2$ for the 1st, $0.8{\sim}0.9cm^2$ for the 2nd-4th on the first growth shoot, and $1.49cm^2$ for the overwintered generation on the second growth shoot. When ALM leaf damage rate was about $53{\sim}73%$, the decrease in the photosynthetic area to the damaged leaf was about $6{\sim}8%$.

• Journal of Bio-Environment Control
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• v.25 no.1
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• pp.57-62
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• 2016

This study was conducted to find out the influence of red LED (Light Emitting Diode) lighting on the photosynthesis, vegetative growth and fruit quality of 'Fuji'/M.26 adult apple tree during night after sunset. The photosynthetic rate, stomatal conductance and transpiration rate at daytime of red LED treatments was not different to those of the control. However, the stomatal conductance and transpiration rate at the nighttime of red LED treatments were lower than those of the control, and the red LED lighting during night after sunset was not induce to photosynthesize at nighttime. In the leaf characteristics, the red LED lighting seemed to increase leaf area and C/N ratio, but decrease SPAD value. The bourse shoot length of the red LED treatments was shorter than that of the control. In the fruit quality, the red LED lighting seemed to increase ethylene production, respiration rate, soluble solid content and fruit red color, and especially the fruit red color tend to increase as the red LED lighting time was longer. In conclusion, the red LED lighting during night after sunset of 'Fuji'/M.26 apple tree promoted the fruit maturation.

• Research in Plant Disease
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• v.21 no.4
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• pp.261-267
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• 2015

During the period from 2013 to 2014, disease occurrences by various pathogens in apple cultivars have been investigated in northern Gyeongbuk province of Korea. Anthracnose, white rot, Alternaria leaf spot, Marssonina blotch, and bacterial shoot blight as major diseases have been observed. Pathogens isolated from the symptomatic plants were identified as Colletotrichum gloeosporioides for anthracnose, Botryosphaeria dothidea for white rot, Alternaria alternata for Alternaria leaf spot, Marssonina mali for Marssonina blotch, and Pseudomonas syringae pv. syringae for bacterial shoot blight. Of all diseases, the bacterial shoot blight has been severely increased in chronically infested fields in Gyeongbuk province.

• Korean Journal of Organic Agriculture
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• v.5 no.1
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• pp.137-147
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• 1996

For the purpose of acquiring microbial agents that can be utilized to biologically control the major airborne diseases to apple trees, such as canker(Botryosphaeria dothidea), bitter rot(Glomerella cingulata), alternaria leaf spot(Alternaria mali), root rot(rosellinia necatrix), canker(Valsa ceratosperma) and gray mold rot(Botrytis cinerea), the effective microorgaisms were isolated, tested for antagonistic activity to the pathogens causing major diseases to apple trees and identifed. Screening of more than 5,000 species of microorganisms collected in nature for them antagonistic action to the pathogens causing 5 major diseases to apple trees resulted in selection of effective species. Out of the 11 species, one species designated as CAP134 demonstrated outstanding activity. The bacterial strain, CAP134 exerted antagonistic efficiency of 57% on an isolated strain and 40% on a donated strain of Botryosphaeria dothidea., 52% on an isolated strain and 46% on a purchased strain of Alternaria mali, 60% on Valsa ceratosperma 25% on Glomerella cingulata, and 64% Rosellinia necatrix. The CAP134 was identified as a bacterial strain to Bacillus subtilis ATCC 6633 based on morephology, culture conditions, and physio-biochemical characteristics.

• Journal of Plant Biotechnology
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• v.46 no.3
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• pp.228-235
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• 2019

Apple (Malus pumila) is one of the most economically important fruits in Korea. but virus infection has decreased the sustainable production of apples and caused serious problems such as yield loss and poor fruit quality. Virus or viroid infection including apple chlorotic leaf spot virus (ACLSV), apple stem pitting virus (ASPV), apple stem grooving virus (ASGV), apple mosaic virus (ApMV) and apple scar skin viroid (ASSVd) have been also reported in Korea. In many cases, as apple gets infected with virus and viroid with no specific symptoms, the damage and symptoms caused by the viruses are not detected. In our research, viruses in the rootstock were eliminated for a virus-free apple dwarfing rootstock of M.9 and M.26. The virus elimination methods were apical meristem culture, thermotherapy ($37^{\circ}C$, 6 weeks) and chemotherapy($Ribavirin^{(R)}$). The detection of apple viruses was accomplished by Enzyme-linked Immuno-Sorbent Assay (ELlSA) and reverse transcription-polymerase chain reaction (RT-PCR). RT- PCR method was 10 ~ 30% more sensitive than the ELISA method. The efficiency of virus elimination was enhanced in apical meristem culture method. The acquisition rate of virus-free apple dwarfing rootstocks was 30 ~ 40% higher in apical meristem culture. After the meristem culturing of M.9, the infection ratio of ACLSV, ASPV and ASGV was 45%, 60% and 50%, respectively. In the apple dwarfing rootstock of M.26, the infection ratio of ACLSV, ASPV and ASGV was 40%, 55% and 55%, respectively. Based on this study, the best method for the production of virus-free apple dwarfing rootstocks was the apical meristem culture.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.5
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• pp.449-455
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• 2016

'Gamhong' apple cultivar which was bred by National Institute of Horticultural and Herbal Science, has high sugar contents, large types of fruit and mid-season types of cultivar. However, 'Gamhong' apple tree is very sensitive cultivar to bitter pit. Therefore, many farms have not solved the problems on bitter pit to cultivate 'Gamhong' apple tree. This study was carried out to find out the exposed length of rootstocks on the occurrence of bitter pit and fruit quality of 'Gamhong'/M.26 apple tree and seek the ideal cultivation strategy to decrease bitter pit to cultivate it. For this research, ten-years-old 'Gamhong'/M.26 apple trees were used. The difference among the treatments of the exposure of rootstock of RL (5 cm), RM (15 cm) and RH (20 cm) from the soil surface was observed with 4 repetition from 2010 to 2011. Decreased exposure of rootstocks resulted in more vigorous growth, taller height, and greater number of shoots. N and K/Ca of RH was tend to be lower than RM and RL, whereas as the exposure of rootstock decreased, fruit weight and bitter pit increased. Therefore, occurrence of bitter pit in RH was significantly lower than that of RM and RL treatment and fruit weight also decreased. There was no difference on nutrient contents of leaf and the fruit quality by the exposed of rootstock in 'Gamhong' M.26 apple tree. To reduce the occurrence of bitter pit, it may be helpful to keep the optimum exposure of rootstock within 20 cm from the soil surface.

• The Plant Pathology Journal
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• v.33 no.6
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• pp.608-613
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• 2017

The full-length sequence of a new isolate of Apple chlorotic leaf spot virus (ACLSV) from Korea was divergent, but most closely related to the Japanese isolate A4, at 84% nucleotide identity. The full-length cDNA of the Korean isolate of ACLSV was cloned into a binary vector downstream of the bacteriophage T7 RNA promoter and the Cauliflower mosaic virus 35S promoter. Chenopodium quinoa was successfully infected using in vitro transcripts synthesized using the T7 promoter, detected at 20 days post inoculation (dpi), but did not produce obvious symptoms. Nicotiana occidentalis and C. quinoa were inoculated through agroinfiltration. At 32 dpi the infection rate was evaluated; no C. quinoa plants were infected by agroinfiltration, but infection of N. occidentalis was obtained.

• The Plant Pathology Journal
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• v.20 no.2
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• pp.142-146
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• 2004

Woody plant tissues contain great amounts of phenolic compounds and polysaccharides. These substances inhibit the activation of reverse transcriptase and/or Taq polymerase in RT-PCR. The commonly used multiple-step protocols using several additives to diminish polyphenolic compounds during nucleic acid extraction are time consuming and laborious. In this study, sodium sulfite was evaluated as an additive for nucleic acid extraction from woody plants and the efficiency of RT-PCR assay of commercial nucleic acid extraction kits and small-scale dsRNA extraction was compared. Sodium sulfite was used as an inhibitor against polyphenolic oxidases and its effects were compared in RNA extraction by commercial extraction kit and small-scale double-stranded RNA (dsRNA) extraction method for RT-PCR. During nucleic acid extraction, addition of 0.5%-1.5%(w/v) of sodium sulfite to lysis buffer or STE buffer resulted in lighter browning by oxidation than extracts without sodium sulfite and improved the RT-PCR detection. When commercial RNA extraction kit was used, optimal concentrations of sodium sulfite were variable according to the tested plant. However, with dsRNA as RT-PCR template, sodium sulfite 1.5% in STE buffer improved the detection efficiency of Apple chlorotic leaf spot virus (ACLSV) and Apple stem grooving virus (ASGV) in fruit trees, and reduced the unspecific amplifications signi-ficantly. Furthermore, when viruses existed at low titers in host plant, small-scale dsRNA extractions were very reliable.

• The Plant Pathology Journal
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• v.32 no.5
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• pp.441-451
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• 2016

Deep sequencing has generated 52 contigs derived from five viruses; Apple chlorotic leaf spot virus (ACLSV), Apple stem grooving virus (ASGV), Apple stem pitting virus (ASPV), Apple green crinkle associated virus (AGCaV), and Apricot latent virus (ApLV) were identified from eight apple samples showing small leaves and/or growth retardation. Nucleotide (nt) sequence identity of the assembled contigs was from 68% to 99% compared to the reference sequences of the five respective viral genomes. Sequences of ASPV and ASGV were the most abundantly represented by the 52 contigs assembled. The presence of the five viruses in the samples was confirmed by RT-PCR using specific primers based on the sequences of each assembled contig. All five viruses were detected in three of the samples, whereas all samples had mixed infections with at least two viruses. The most frequently detected virus was ASPV, followed by ASGV, ApLV, ACLSV, and AGCaV which were withal found in mixed infections in the tested samples. AGCaV was identified in assembled contigs ID 1012480 and 93549, which showed 82% and 78% nt sequence identity with ORF1 of AGCaV isolate Aurora-1. ApLV was identified in three assembled contigs, ID 65587, 1802365, and 116777, which showed 77%, 78%, and 76% nt sequence identity respectively with ORF1 of ApLV isolate LA2. Deep sequencing assay was shown to be a valuable and powerful tool for detection and identification of known and unknown virome in infected apple trees, here identifying ApLV and AGCaV in commercial orchards in Korea for the first time.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.8
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• pp.3312-3327
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• 2020

Plant diseases are a significant yield and quality constraint for farmers around the world due to their severe impact on agricultural productivity. Such losses can have a substantial impact on the economy which causes a reduction in farmer's income and higher prices for consumers. Further, it may also result in a severe shortage of food ensuing violent hunger and starvation, especially, in less-developed countries where access to disease prevention methods is limited. This research presents an investigation of Directional Local Quinary Patterns (DLQP) as a feature descriptor for plants leaf disease detection and Support Vector Machine (SVM) as a classifier. The DLQP as a feature descriptor is specifically the first time being used for disease detection in horticulture. DLQP provides directional edge information attending the reference pixel with its neighboring pixel value by involving computation of their grey-level difference based on quinary value (-2, -1, 0, 1, 2) in 0°, 45°, 90°, and 135° directions of selected window of plant leaf image. To assess the robustness of DLQP as a texture descriptor we used a research-oriented Plant Village dataset of Tomato plant (3,900 leaf images) comprising of 6 diseased classes, Potato plant (1,526 leaf images) and Apple plant (2,600 leaf images) comprising of 3 diseased classes. The accuracies of 95.6%, 96.2% and 97.8% for the above-mentioned crops, respectively, were achieved which are higher in comparison with classification on the same dataset using other standard feature descriptors like Local Binary Pattern (LBP) and Local Ternary Patterns (LTP). Further, the effectiveness of the proposed method is proven by comparing it with existing algorithms for plant disease phenotyping.