• 한국균학회소식:학술대회논문집
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• 한국균학회 2014년도 춘계학술대회 및 임시총회
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• pp.37-37
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• 2014

Glomerella leaf spot pathogens can infect apple leaves, causing extensive necrosis and premature defoliation, as well as necrotic spots on fruit. In recent years, the disease has been reported with increasing frequency in China, and appears to be spreading rapidly in some apple-producing areas. In this study, fungal isolates from diseased apples leaves collected in Henan and Shaanxi provinces were analyzed based on morphology, cultural characters, pathogenicity and molecular phylogenetics. It was found that Glomerella leaf spot of apple was caused by two pathogens, Colletotrichum fructicola and C. aenigma. Pathogenicity tests showed that C. fructicola and C. aenigma could infect apple leaves of cultivar Golden Delicious, as well as Gala, Qinguan, Pink Lady, Pacific Rose, Golden Century and Honeycrisp, all of which include Golden Delicious in their parentage. In wound inoculation experiments, C. fructicola and C. aenigma were pathogenic to fruit of Gala, Qinguan, Golden Delicious, Pacific Rose, Starkrimson and Fuji. With non-wounded fruit, C. fructicola was pathogenic to Gala and Golden Delicious, and C. aenigma was pathogenic to Gala. It is concluded that the two pathogens could be differentiated according to pathogenicity to leaves and fruits of different apple cultivars.

• 원예과학기술지
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• 제34권5호
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• pp.708-718
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• 2016

Two different pest control programs were applied on 8-year-old 'Ryoka'/M.26 apple trees (Malus domestica Borkh.). Lime sulfur or Bordeaux mixture with emulsified oil were applied 12 times from late March to mid-September as organic treatment, and synthetic chemicals were 7 times applied as control treatment. Over the entire apple-growing season, photosynthesis rates of apple trees were significantly lower in the organic treatment than in the control, and this photosynthetic differences were larger in July and August. Photosynthesis-related parameters such as stomatal conductance and transpiration behaved similarly to photosynthesis. The leaf area in the organic treatment was significantly smaller ($24.7cm^2$) than that in the control treatment ($30.7cm^2$). Organic leaves contained significantly less Chl. a ($15.5mg{\cdot}g^{-1}$) than did control leaves ($17.6mg{\cdot}g^{-1}$). Fruit yield per tree was significantly lower in the organic treatment (18.8 kg) than in the control (24.5 kg), because organic fruits experienced a higher rate of disease infection such as white rot (Botryosphaeria dothidae) and bitter rot (Glomerella cingulata) than did control fruits. Organic fruits had high flesh firmness but less color development (lower Hunter's a values). In this experiment, the pest control program with frequent applications of organic fungicides showed negative effects on photosynthesis and disease infection on leaves and fruits, and thus reduce the fruit quality and yield in 'Ryoka'/M.26 apple trees.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 1999년도 임시총회 및 추계 학술발표회
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• pp.29.1-29
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• 1999

• The Plant Pathology Journal
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• 제25권3호
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• pp.291-293
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• 2009

The low virus titer in woody plant tissues and the presence of inhibitor compounds such as polyphenols, tannins and polysaccharides are common difficulties that compromise purification of plant viroids from their woody hosts. A simple, reliable method of RNA isolation using CF11 cellulose column on a microcentrifuge tube scale for detecting Apple scar skin viroid (ASSVd) in apple was developed. Total RNA extracted from leaf, woody bark and the fruit skin was used for reverse transcription. RT-PCR products could be detected from RNA prepared from dormant woody bark, fruit skin and fresh leaves with both the CF11 cellulose column method and NucliSens extractor in February, August and November. Meanwhile, with the RNeasy kit RT-PCR, products were detected only in leaves and not from bark or fruit skin. The PCR product, about 330 base pairs, was analyzed by agarose gel electrophoresis. The CF11 cellulose column method was effective for detecting ASSVd. The method enabled the processing of a large numbers of samples of dormant woody bark, leaf and fruit skin of apple.

• 한국토양비료학회지
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• 제33권4호
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• pp.242-246
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• 2000

근적외 분광분석기를 이용하여 과수의 영양진단을 위한 신속한 엽분석 수단으로 활용하고자 본 시험을 수행하였다. 사과 '후지'품종 잎 177점, 포도 '캠벨얼리' 품종 잎130점의 시료를 이용하여 1,100~2.500nm까지 근적외영역의 흡수스펙트럼을 측정하였다. 총질소 분석은 살리실산-황산으로 분해후 켈달 증류하여 측정하였다. 근적외 스펙트럼과 총 질소함량과의 상관분석을 이용, 검량식을 개발하였고 화학분석한 결과에 대한 예측식을 구하였다. 사과는 중회귀계수 0.965, 검량식의 표준오차 0.086, 포도는 중회귀계수 0.926, 검량식의 표준오차 0.152이었다. 개발된 검량식을 이용하여 예측식을 작성한 결과는 사과의 경우 0.360, 포도 0.210의 결과를 얻었다. 지역간, 년차간 발생되는 변이가 보정된다면 신속한 엽분석 수단이 될 것으로 판단된다.

• The Plant Pathology Journal
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• 제39권4호
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• pp.397-408
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• 2023

Fire blight disease, caused by Erwinia amylovora, is a devastating affliction in apple cultivation worldwide. Chemical pesticides have exhibited limited effectiveness in controlling the disease, and biological control options for treating fruit trees are limited. Therefore, a relatively large-scale survey is necessary to develop microbial agents for apple trees. Here we collected healthy apple trees from across the country to identify common and core bacterial taxa. We analyzed the endophytic bacterial communities in leaves and twigs and discovered that the twig bacterial communities were more conserved than those in the leaves, regardless of the origin of the sample. This finding indicates that specific endophytic taxa are consistently present in healthy apple trees and may be involved in vital functions such as disease prevention and growth. Furthermore, we compared the community metabolite pathway expression rates of these endophyte communities with those of E. amylovora infected apple trees and discovered that the endophyte communities in healthy apple trees not only had similar community structures but also similar metabolite pathway expression rates. Additionally, Pseudomonas and Methylobacterium-Methylorobrum were the dominant taxa in all healthy apple trees. Our findings provide valuable insights into the potential roles of endophytes in healthy apple trees and inform the development of strategies for enhancing apple growth and resilience. Moreover, the similarity in cluster structure and pathway analysis between healthy orchards was mutually reinforcing, demonstrating the power of microbiome analysis as a tool for identifying factors that contribute to plant health.

• The Plant Pathology Journal
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• 제39권1호
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• pp.88-107
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• 2023

In the present investigation, bacterial isolates from infected apple trees causing apple canker during winter were studied in the northern Gyeongbuk Province, Korea. The pathogen was identified as Pseudomonas syringae pv. syringae (Pss) through various physiological and biochemical characterization assays such as BIOLOG, gas chromatography of fatty acid methyl esters, and 16S rRNA. Bioassays for the production of phytotoxins were positive for syringopeptin and syringomycin against Bacillus megaterium and Geotrichum candidum, respectively. The polymerase chain reaction (PCR) method enabled the detection of toxin-producing genes, syrB1, and sypB in Pss. The differentiation of strains was performed using LOPAT and GATTa tests. Pss further exhibited ice nucleation activity (INA) at a temperature of -0.7℃, indicating an INA⁺ bacterium. The ice-nucleating temperature was -4.7℃ for a non-treated control (sterilized distilled water), whereas it was -9.6℃ for an INA^- bacterium Escherichia coli TOP10. These methods detected pathogenic strains from apple orchards. Pss might exist in an apple tree during ice injury, and it secretes a toxin that makes leaves yellow and cause canker symptoms. Until now, Korea has not developed antibiotics targeting Pss. Therefore, it is necessary to develop effective disease control to combat Pss in apple orchards. Pathogenicity test on apple leaves and stems showed canker symptoms. The pathogenic bacterium was re-isolated from symptomatic plant tissue and confirmed as original isolates by 16S rRNA. Repetitive element sequence-based PCR and enterobacterial repetitive intergenic consensus PCR primers revealed different genetic profiles within P. syringae pathovars. High antibiotic susceptibility results showed the misreading of mRNA caused by streptomycin and oxytetracycline.

• 한국잡초학회지
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• 제7권3호
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• pp.337-347
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• 1987

Oxyfluorfen 살포(撒布)에 따른 과수종류(果樹種類) 및 품종간(品種間)의 표류비수(漂流飛數) 및 휘산해(揮散害) plastic house에서 조사(調査)하였고, 또한 사과에 대한 살포시기별(撒布時期別) 약해반응(藥害反應)을 포장(圃場)에서 비교(比較)하였다. 가. 수종(數種) 및 품종별(品種別) 약해반응(藥害反應) (1) 발아율감소(發芽率減少)에 미치는 oxyfluorfen의 해(害)를 보면 표류비산해(漂流飛散害) 및 휘산해(煇散害)가 비슷한 정도(程度)로 영향을 주었고 과수종류별(果樹種類別)로는 배와 복숭아가 사과보다 심하였다. (2) 신초당(新梢當) 엽수감소율(葉數減少率)은 사과와 복숭아가 배보다 컸으며 잎의 피해증상(被害症狀)은 배에서 가장 빨리 그러고 심하게 발현되었고 복숭아에서는 가장 경미하고 완만하였다. 피해요인별(被害要因別)로 보면 사과와 배에서는 표류비산해(漂流飛散害)와 휘산해(煇散害)를, 복숭아는 주로 휘산해(煇散害)를 받는 경향이었다. (3) 신초생장억제정도(新梢生長抑制程度)는 복숭아에 비하여 사과와 배에서 컷고, 배는 억제(抑制)가 급진적(急進的)이었으나 사과는 비교적 완만하게 진행(進行)되었다. 약해요인별(藥害要因別)로는 표류비산해(漂流飛散害)와 휘산해(煇散害)가 비슷한 정도(程度)로 나타났다. 나. 약제처리시기별(藥劑處理時期別) 약해반응(藥害反應) (1) Oxyfluorfen은 사과유목(幼木)의 발아(發芽)를 지연시켰는데 지연정도(程度)는 발아기(發芽期) 이전(以前)의 살포(撒布)가 발아기(發芽期)에서 발아완료기(發芽完了期) 사이에 살포(撒布)한 것보다 적었으나 최종 발아(發芽)된 수(數)는 oxyfluorfen 살포(撒布)에 의한 영향을 받지 않았다. 피해엽수(被害葉數)는 처리시기간(處理時期間)에 차이(差異)가 없었으나 피해정도(被害程度)는 발아전(發芽前) 살포(撒布)가 가벼웠다. (2) 신초당(新梢當) 엽수(葉數)와 묘목당(苗木當) 총신초생장량(總新梢生長量) oxyfluorfen의 어느 시기처리(時期處理)에서나 발아후(發芽後) 약 40일까지는 감소(減少)가 인정되었으나 신초생장(新梢生長)이 왕성한 5월 중순 이후에는 처리간(處理間)의 차이(差異)가 거의 없어졌다.

• 한국환경농학회지
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• 제42권4호
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• pp.396-407
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• 2023

The golden apple snail (Pomacea canaliculata) has been utilized as a natural and eco-friendly control of weeds in rice paddy fields. However, P. canaliculata can damage other crops. In this study, the effectiveness of plant extracts from various natural sources that are reportedly effective against pests in the control of P. canaliculata was investigated. The four plant extracts were effective against P. canaliculata and ranked in descending order as green tea seed (Camellia sinensis) > root of red spider lily (Lycoris radiata) > leaves of tobacco (Nicotiana tabacum) > root of sophora (Sophora flavescens). The mortality rate of P. canaliculata was increased using 200 to 2000 mg/kg of green tea seed powder. However, shrubby sophora root extract did not significantly increase the mortality rate. The LC₅₀ and LC₉₀ of green tea seed, tobacco leaves, shrubby sophora root, and red spider lily root were 900 and 2800 mg/L, 956 and 2320 mg/L, 2162 and 5325 mg/L, and 512 and 1054 mg/kg, respectively. The LC₅₀ and LC₉₀ of ground powder of C. sinensis, N. tabacum, S. flavescens and L. radiata were 248 and 646 mg/L, 403 and 733 mg/L, 409 and 905 mg/L, and 493 and 1141 mg/L, respectively. The findings indicate the remarkable control potency of green tea seeds against the golden apple snail. An organic material incorporating the four plant powders may help control green apple snail in an ecosystem-friendly manner.

• Current Research on Agriculture and Life Sciences
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• 제11권
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• pp.91-99
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• 1993

경북지방(慶北地方)사과원(園)의 사과나무 개식장해(改植障害) 발생여부(發生(與否)와 발생정도(發生程度)를 밝힐 목적(目的)으로 20년이상(年以上) 사과재배(栽培)가 계속되고 있는 23개(個) 사과원(園)의 토양(土壤)을 채취(採取)하여, 토양소독(土壤消毒)에 의(依)한 사과실생묘(實生苗)의 생장(生長)과 개식장해(改植障害)에 관련(關聯)된 것으로 알려진 몇 가지 요인(要因)을 조사(調査)한 결과(結果)는 다음과 같았다. 1. 사과실생묘(實生苗)의 생장(生長)은 6개(個) 과원(果園)에서 유의차(有意差)가 있었고, 가장 큰 차이(差異)를 나타낸 과원(果園)에서 38% 증가(增加)되었다. 2. 생체중(生體重)에서는 지하부(地下部)가 4개원(個園), 지하부(地下部)가 10개원(個園) 전생체중(全生體重)에서는 9개원(個園)에서 유의차(有意差)를 나타내었고, 지상부(地上部)에서 토양소독(土壤消毒)에 의(依)한 차이(差異)가 가장 현저(顯著)하였으며, 5개과원(個果園)에서는 50%이상(以上) 증가(增加)되었다. 3. 토양중(土壤中)의 Cu 및 As 농도(濃度), 토양선충수(土壤線蟲數)는 사과실생묘(實生苗)의 생장(生長)과 생체중(生體重)에 뚜렷한 영향(影響)을 미치지 않았다. 4. 토양(土壤) PH와 개식장해발생간(改植障害發生間)에는 뚜렷한 관계(關係)를 확인(認定)할 수 없었다.