• Title/Summary/Keyword: Orchards

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Morphological and Genetic Characteristics of Colletotrichum gloeosporioides Isolated from Newly Emerging Static-Symptom Anthracnose in Apple

  • Jeon, Yongho;Cheon, Wonsu
    • 한국균학회소식:학술대회논문집
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    • 2014.10a
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    • pp.34-34
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    • 2014
  • Filamentous fungi of the genus Colletotrichum (teleomorph, Glomerella) are considered major plant pathogens worldwide. Cereals, legumes, vegetables, and fruit trees may be seriously affected by this pathogen (1). Colletotrichum species cause typical disease symptoms known as anthracnoses, characterized by sunken necrotic tissue, where orange conidial masses are produced. Anthracnose appears in both developing and mature plant tissues (2). We investigated disease occurrence in apple orchards from 2013 to 2014 in northern Gyeongbuk province, Korea. Typical anthracnose with advanced symptoms was observed in all apple orchards studied. Of late, static fruit spot symptoms are being observed in apple orchards. A small lesion, which does not expand further and remains static until the harvesting season, is observed at the beginning of fruit growth period. In our study, static symptoms, together with the typical symptoms, were observed on apples. The isolated fungus was tested for pathogenicity on cv. 'Fuji apple' (fully ripe fruits, unripe fruits, and cross-section of fruits) by inoculating the fruits with a conidial suspension (105105 conidia/ml). In apple inoculated with typical anthracnose fungus, the anthracnose symptoms progressed, and dark lesions with salmon-colored masses of conidia were observed on fruit, which were also soft and sunken. However, in apple inoculated with fungi causing static symptoms, the size of the spots did not increase. Interestingly, the shape and size of the conidia and the shape of the appressoria of both types of fungi were found to be similar. The conidia of the two types of fungi were straight and cylindrical, with an obtuse apex. The culture and morphological characteristics of the conidia were similar to those of C. gloeosporioides (5). The conidia of C. gloeosporioides germinate and form appressoria in response to chemical signals such as host surface wax and the fruitripening hormone ethylene (3). In this study, the spores started to germinate 4 h after incubation with an ethephon suspension. Then, the germ tubes began to swell, and subsequently, differentiation into appressoria with dark thick walls was completed by 8 h. In advanced symptoms, fungal spores of virtually all the appressoria formed primary hyphae within 16 h. However, in the static-symptom fungus spores, no primary hyphae formed by 16 h. The two types of isolates exhibited different growth rates on medium containing apple pectin, Na polypectate, or glucose as the sole carbon. Static-symptom fungi had a >10% reduction in growth (apple pectin, 14.9%; Na polypectate, 27.7%; glucose, 10.4%). The fungal isolates were also genetically characterized by sequencing. ITS regions of rDNA, chitin synthase 1 (CHS1), actin (ACT), and ββ-tubulin (βtβt) were amplified from isolates using primer pairs ITS 1 and ITS 4 (4), CHS-79F and CHS-354R, ACT-512F and ACT-783R, and T1 and βt2βt2 (5), respectively. The resulting sequences showed 100% identity with sequences of C. gloeosporioides at KC493156, and the sequence of the ββt gene showed 100% identity with C. gloeosporioides at JX009557.1. Therefore, sequence data from the four loci studied proves that the isolated pathogen is C. gloeosporioides. We also performed random amplified polymorphic DNA-PCR, which showed clearly differentiated subgroups of C. gloeosporioides genotypes. The clustering of these groups was highly related to the symptom types of the individual strains.

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Effects of Humidity and Citrus Leaf Age on the Multiplication of Aculops pelekassi (Acari: Eriophyoidea) and Seasonal Population Abundances in Citrus Orchards (습도와 감귤 잎의 연령이 귤녹응애 증식에 미치는 영향 및 감귤원에서 발생소장)

  • Seo, Yon Dong;Kim, Dong-Soon
    • Korean journal of applied entomology
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    • v.53 no.1
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    • pp.1-6
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    • 2014
  • The pink citrus rust mite, Aculops pelekassi (Keifer) (Acari: Eriophyoidea), is an important pest in the citrus orchards of Jeju, Korea. This study was performed to investigate the seasonal population abundance of A. pelekassi, and the effects of humidity and citrus leaf age on the multiplication of this pest. Relative humidity (RH) significantly affected the longevity and fecundity of A. pelekassi. Longevity was 7.5, 14.5 and 14.6 d and fecundity was 5.4, 21.5, and 27.1 eggs at 33, 75 and 84% RH, respectively. The leaf age of citrus significantly affected the multiplication of A. pelekassi. The population abundance on 40 day-old leaves was much higher more than 3 times that on 10-day old leaves at 4 weeks after introduction. Overwintered A. pelekassi adults between the bud scales of the citrus trees became active in late April; they were found on newly emerged leaves, followed by their settlement on young fruits in mid-June. The population levels of A. pelekassi peaked on the leaves in late June to July, and on the fruits in early August. The results obtained in this study should be useful for the control of A. pelekassi in citrus orchards in Jeju.

The Colonizing Routes of Aphis gossypii (Hemiptera: Aphididae) to Mandarine Citrus Trees Grown in a Non-heating Plastic-film House During the Early Season (무가온 시설재배 감귤에서 계절초기 목화진딧물 개체군의 정착경로에 관한 연구)

  • Kim, Tae Ok;Kwon, Soon Hwa;Park, Jeong Hoon;Oh, Sung Oh;Hyun, Seung Young;Kim, Doog-Soon
    • Korean journal of applied entomology
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    • v.54 no.3
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    • pp.247-255
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    • 2015
  • The cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae) infests citrus orchards, causing sooty mold damage to the fruits. This study was conducted to investigate the colonizing route of A. gossypii in citrus orchards in a non-heating plastic-film house during the early season. The overwintering eggs of the aphids are frequently found on summer shoots of the citrus trees. The eggs were mostly those of Aphis citricola, without any A. gossypii when hatched. The colonization of citrus trees by alate A. gossypii in non-heating plastic-film houses was mainly observed twice, with advanced flight in late April and delayed flight in late May. The delayed flight was synchronized with the timing of the emergence of alate A. gossypii from the fundatrix generation in the holocyclic life cycle. During advanced flight in closed citrus orchards, alate A. gossypii were caught in yellow water traps installed in the fields, and the populations were found to originate from the surviving populations of the anholocyclic life cycle. Consequently, we concluded that citrus tree colonization with A. gossypii occurred during the advanced flight of the anholocyclic and the delayed flight of the holocyclic life cycle.

The Uneven Distribution of Mating Type Genes in Natural and Cultivated Truffle Orchards Contributes to the Fructification of Tuber indicum

  • Li, Qiang;Fu, Yu;Sun, Qun;Sourzat, Pierre;Yang, Mei;Liu, Chengyi;Tan, Hao;Ye, Lei;Zou, Jie;Wu, Chenguang;Zhang, Bo;Li, Xiaolin
    • Mycobiology
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    • v.46 no.1
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    • pp.64-71
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    • 2018
  • The aim of this study was to investigate the pattern of distribution of mating type (MAT) genes of Tuber indicum in ectomycorhizosphere soils from natural T. indicum-producing areas and cultivated truffle orchards and ascocarp samples from different regions. Quantitative real-time PCR and multiplex PCR were used to weight the copy numbers of MAT1-1-1 and MAT1-2-1 in natural truffle soils and cultivated orchard soils. The effect of limestone on the pattern of truffle MAT genes and the correlation between soil properties and the proportion of MAT genes were also assessed. These results indicated that an uneven and nonrandom distribution of MAT genes was common in truffle-producing areas, cultivated truffle orchards, and ascocarps gleba. The competition between the two mating type genes and the expansion of unbalanced distribution was found to be closely related to truffle fructification. Limestone treatments failed to alter the proportion of the two mating type genes in the soil. The content of available phosphorus in soil was significantly correlated with the value of MAT1-1-1/MAT1-2-1 in cultivated and natural ectomycorhizosphere soils. The application of real-time quantitative PCR can provide reference for monitoring the dynamic changes of mating type genes in soil. This study investigates the distributional pattern of T. indicum MAT genes in the ectomycorhizosphere soil and ascocarp gleba from different regions, which may provide a foundation for the cultivation of T. indicum.

Selection of Earthworm for Bioindicators in Agroecosystem (농생태계 지렁이 생물지표종 선발)

  • Kim, Tae-Heung;Hong, Yong;Choi, Nak-Jung
    • Korean Journal of Environmental Biology
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    • v.27 no.1
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    • pp.40-47
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    • 2009
  • Heavy reliance on organosynthetic chemical methods to control agricultural pest tends to deteriorate and lower fertility of soil. We studied annual occurrence of earthworm in environment-friendly agroecosystem and attempted to determine the degree of soil contamination. Candidate bioindicators of earthworm in agroecosystem were selected through analysis of earthworm diversities. Depending on the degree of pesticide use, the fields were devided into conventional, less-pesticide, pesticide free, and organic fields. A nearby field not in agricultural use was chosen as a control. This study was carried out in the greenhouses (lettuce and grape) in 2006 and in orchards (apple, pear, peach, citrus and grape) in 2007. Earthworm was collected from 50 ×× 50 ×× 10 cm33 of respective soil. We found 11 species from 5 genera and 3 families, and 12 species from 4 genera and 3 families in the greenhouses and in orchards, respectively. The contents of organic matter in soil in the greenhouses were variable but quite less so in orchards. Amynthas heteropodus occurred most frequently in both sites suggesting that it could be adopted as a bioindicator in agroecosystem in Korea.

The Survey of Weed Occurrence at Grape Orchard in Chungnam Province (충남지역 포도원에서 발생하는 잡초분포조사)

  • Hwang, Ki Seon;Roh, Sug-Won;Lee, Youn Me;Kim, Ji Yoon;Lee, Jeong Sun;Lee, In-Yong;Park, Kee Woong
    • Weed & Turfgrass Science
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    • v.5 no.3
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    • pp.177-180
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    • 2016
  • This study was conducted to identify problematic weed species in grape orchard fields to establish basic information for suitable weed control. Surveys of weed species occurring in grape orchards were conducted in Chungnam province including Daejeon and Sejong of Korea from April to June and from September to October in 2015. From the surveys, 50 weed species belonging to 23 families (33 annuals and 17 perennials) were identified. In the first survey, the most dominant weed species by the importance values was Poa annua (7.07) followed by Echinochloa crus-galli (6.56), Digitaria ciliaris (6.43) and Capsella bursapastoris (5.63). In the second survey, Rorippa palustris (9.59), Eclipta alba (9.13), Digitaria ciliaris (7.68) and Poa annua (7.68) were dominant. Different weed species and dominance patterns were detected according to weed control methods in the grape orchards. Seven weed species belonging to six families were identified in the field in which herbicides were being used as a weed control method. However, most weed species (21 species belonging to 9 families) were occurred in the mowing + tillage fields. These surveys provide information about seasonal variations of weeds species occurred in grape orchards and impact of different weed control methods on the weed occurrence.

Effect of Soil Sulfur treatment on Apple Valsa Canker (유황토분 처리가 사과 부란병에 미치는 영향)

  • Chun, Ik-Jo;Park, Seung-Min
    • Korean Journal of Organic Agriculture
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    • v.25 no.1
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    • pp.125-134
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    • 2017
  • This study was carried out to examine the effects of soil sulfur mixture on the control apple valsa canker in apple orchard for two years. In organic apple orchard, The recovery percentages of apple valsa canker were compared among control (no treatment), lime sulfur, and soil sulfur in organic orchards. In conventional apple orchards, those of recovery percentages were compared among control, neoasozin, lime sulfur, and soil sulfur. Compared with control, soil sulfur treatments significantly improved the recovery percentages of apple valsa canker infected trees in organic orchard. However, there were no differences between lime sulfur and soil sulfur treatment in organic apple orchard, except BongHyun orchard experiment in 2013. Compared with control fruit qualities, fruit skin red color and fruit firmness were improved in lime sulfur and soil sulfur treatment, respectively. In conventional orchard, apple trees treated with lime sulfur, soil sulfur or neoasozin improved recovery percentages, compared with those of control trees. Soil sulfur treatments recovered 87.5~97.5% of infected 'Fuji'/MM106 apple trees in organic and conventional apple orchards. The trees applied with neoasozin showed significant lower shoot growth than those of soil sulfur treatment in conventional orchard. Soli sulfur treatment improved fruit red color, but did not affected fruit weight, fruit firmness, soluble solids concentrations, and titratable acidity.

Growth of One-Year-Old Pot-Cultivated 'Fuji'/M.9 Apple Trees under Different Concentrations of Nitrogen Fertilization (질소시비농도에 따른 1년생 사과 'Fuji'/M.9 포트묘목의 수체 생장)

  • Ha, Woongyong;Shin, Hyunsuk;Lim, Heon-Kyu;Oh, Youngjae;Han, Hyeondae;Kim, Keumsun;Oh, Sewon;Kwon, Yeuseok;Kim, Daeil
    • Korean Journal of Plant Resources
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    • v.32 no.5
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    • pp.499-508
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    • 2019
  • The study was carried out to investigate growth of 48.6-L pot-cultivated 1-year-old 'Fuji'/M.9 apple trees depending on different levels of nitrogen concentration. While rise in tree growth was paralleled with increase of nitrogen concentration, more than 32 mM of nitrogen rather restrained tree growth. In particular, growth of 16 mM of nitrogen treated trees was satisfied with criteria for production of high-quality pot-cultivated nursery stocks. Although mineral contents of leaves were higher in 8 and 16 mM nitrogen treatments than commonly recommended mineral contents in apple orchards, such somewhat surplus minerals could be helpful for tree growth after transplanting to apple orchards. In addition, our result indicated that soils of 8 and 16 mM of nitrogen treated pots met appropriate criteria for soil chemical property of apple orchards. Thus, in the light of tree growth, mineral contents of leaves, and soil chemical property in the pots, 16 mM of nitrogen treatment is considered to be suitable for production of 1-year-old 'Fuji'/M.9 apple potted trees.

Influence of (E)-2-hexenyl (Z)-3hexenoate on the Occurrence of Egg Parasitoids, Ooencyrtus nezarae (Hymenoptera: Encyrtidae) and Gryon japonicum (Hymenoptera: Scelionidae), in Apple Orchards (사과원에서 (E)-2-hexenyl (Z)-3hexenoate 성분이 노린재깡충좀벌(Ooencyrtus nezarae)(Hymenoptera: Encyrtidae)과 노린재기생알벌(Gryon japonicum) (Hymenoptera: Scelionidae) 발생에 미치는 영향)

  • Baek, Seonghoon;Park, Chung Gyoo;Seo, Bo Yoon;Cho, Jum Rae;Park, Chang-Gyu
    • Korean journal of applied entomology
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    • v.60 no.1
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    • pp.91-98
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    • 2021
  • The populations of Riptortus pedestris (Fabricius) cause serious economic damages in local apple orchards. However, there was no study to manage its populations with environment friendly tactics. Thus, this study was conducted to analyze its attraction effects of one of R. pedestris aggregation pheromone compounds, (E)-2-hexenyl (Z)-3hexenoate (E2HZ3H), to its parasitoids, Ooencyrtus nezarae (Ishii) and Gryon japonicum (Ashmead). This compound did not increase the number of these two parasitoids and change its spatial distribution. However, this compound could attract two parasitoids within limited distance. These results indicates that one compound of R. pedestris aggregation pheromone, E2HZ3H, could be a good candidate to manage R. pedestris populations in conditions that its populations locally occurs in apple orchards.

Outbreak of Fire Blight of Apple and Pear and Its Characteristics in Korea in 2019 (2019년 국내 사과와 배 화상병 대발생과 그 특징)

  • Ham, Hyeonheui;Lee, Kyong Jae;Hong, Seong Jun;Kong, Hyun Gi;Lee, Mi-Hyun;Kim, Hyun-Ran;Lee, Yong Hwan
    • Research in Plant Disease
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    • v.26 no.4
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    • pp.239-249
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    • 2020
  • To find out the cause of the fire blight outbreak in apples and pears of Korea in 2019, we investigated disease appearing situation of thirty fire blight infected orchards, and interviewed farmers to determine the cultivation characteristics. Fire blight occurred mostly in orchards that had infected more than 2 years before. The cause of this were as follows: farmers did not know the symptoms of the disease properly. It is presumed that it has spread from the first occurrence to the surrounding orchards by flower-visiting insects or farmers and to a short distance or a long distance by the same cultivator or co-farmer. These series of processes repeated in the newly spreading area, and then disease reports increased as farmers became aware of fire blight. To minimize the spread of fire blight in Korea, it suggested that thorough education of farmers for early diagnosis and quantitative detection technology that can diagnose even in no symptom showing plants. And chemical or biological spraying systems suitable for domestic cultivation methods, which are producing large fruits, and molecular epidemiological studies of pathogens.