• Title/Summary/Keyword: Apple orchards

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Survival of Erwinia amylovora on Surfaces of Materials Used in Orchards

  • Choi, Hyun Ju;Kim, Yeon Ju;Lim, Yeon-Jeong;Park, Duck Hwan
    • Research in Plant Disease
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    • v.25 no.2
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    • pp.89-93
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    • 2019
  • Fire blight disease caused by the bacterium, Erwinia amylovora, was observed in apple and pear orchards in Korea in 2015. Since then, it has spread, sometimes over long distances to other orchards. Therefore, we examined the ability of E. amylovora to survive in soils and on the surfaces of common materials such as T-shirts, wrist bands, pruning shears, and rubber boots by both conventional PCR (cPCR) and quantitative PCR (qPCR) methods. E. amylovora was detected in all materials tested in this study and survived for sufficiently long periods to cause fire blight disease in new sites. Thus, based on the results of this study, sanitation protocols must be applied to equipment during orchard work.

Phylogenetic and Recombination Analysis of Apple Stem Grooving Virus Isolates from Pears in Korea

  • Nam-Yeon Kim;Rae-Dong Jeong
    • Research in Plant Disease
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    • v.29 no.2
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    • pp.193-199
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    • 2023
  • The apple stem grooving virus (ASGV) is one of the most harmful latent viruses infecting pear orchards worldwide. To examine the genetic diversity of ASGV in Korean pear orchards, the complete coat protein (CP) gene of five ASGV isolates collected from various regions were identified. The five Korean ASGV isolates showed 88-96% nucleotide identity with the 11 isolates worldwide occurring elsewhere in the world. Phylogenetic analysis of five isolates, as well as the previously sequenced isolates, indicated that the ASGV clusters had no correlation with the host or geographical regions of origin. Recombination analysis showed that one of the five Korean isolates is a recombinant, with a recombination site in the CP gene region (nt 532-708). This study is the first report of natural recombination within the CP gene of ASGV isolates from pears grown in Korea.

Seven Unrecorded Species of Ascomycota Isolated from the Rhizosphere Soils of Apple and Pear Trees in Korea

  • Hyeongjin Noh;Hyun Uk Cho;Jun Woo Cho;Seong Jae Ahn;Seong Hwan Kim
    • The Korean Journal of Mycology
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    • v.51 no.4
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    • pp.471-490
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    • 2023
  • Soil is a rich source of saprobic and pathogenic fungi in crop cultivation areas. Compared with that of the fruit trees, scarce information is available regarding the fungi present in orchard soils in Korea. We sampled rhizosphere soils of apple and pear trees from several orchards in Cheongju, Anseong, and Cheonan, Korea. During the processing of soil fungi, seven unrecorded species of the phylum Ascomycota were isolated. These included Acrocalymma walkeri, Clonostachys krabiensis, Coniella vitis, Cosmospora diminuta, Lasiobolidium spirale, Penicillium vallebormidaense, and Pseudothielavia arxii. All the species were identified and described based on morphological characteristics and molecular analysis of the ITS1-5.8S-ITS2 region and the large subunit of nuclear ribosomal RNA gene and partial β-tubulin gene (BenA) sequences. Descriptions and illustrations of the morphological characteristics are provided.

Correlation between the Dieback Ratio and Cultivation Environment for Apple Orchards Infected by Soil-Borne Diseases in Chungbuk Province (충북에서 사과 주요 토양병에 의한 고사율과 재배환경과의 상관관계)

  • Lee, Sung-Hee;Kwon, Yeuseok;Shin, Hyunman;Kim, Ik-Jei;Nam, Sang-Young;Hong, Eui Yon;Kim, Daeil;Cha, Jae-Soon
    • Research in Plant Disease
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    • v.23 no.1
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    • pp.49-55
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    • 2017
  • The previous study showed that die-back of apple trees caused by soil-borne diseases was significantly high in the apple orchards in Chungbuk province. The correlation between dieback ratio and cultivation environment in apple orchards infected by soil-borne diseases was investigated in this study. The dieback ratio of five orchards diseased by violet root rot and five places infected by white root rot showed significantly positive correlation with Ca content and available $P_2O_5$ content in soil, respectively. Whereas, the dieback ratio of fourteen orchards diseased by Phytophthora root rot was not significant. Subgrouping of cultivation environment analysis showed that the slope degree of orchard and the number of fruit setting also affected the dieback ratio caused by violet root rot and Ca content in soil also affected the dieback ratio caused by white root rot. It showed that the slope degree, soil texture, Mg and Ca content affected the dieback ratio caused by Phytophthora root rot. These results can be applied to reduce die-back ratio by the modification cultivation environment for each soil-borne disease.

Current status on the occurrence and management of disease, insect and mite pests in the non-chemical or organic apple orchards (무농약 유기재배 사과원의 병해충 발생 및 관리 실태)

  • Choi, Kyung-Hee;Lee, Dong-Hyuk;Song, Yang-Yik;Nam, Jong-Chul;Lee, Soon-Won
    • Proceedings of the Korean Society of Organic Agriculture Conference
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    • 2009.12a
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    • pp.45-56
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    • 2009
  • Current status on the occurrence and the management of the major disease, insect and mite pests were investigated in the organic or non-chemical pest control orchards from 2005 to 2009. Numbers of certified organic or non-chemical apple orchards were increased from 14 in 2005 to 78 in 2008. Severe damages on leaves and fruits occurred by the several diseases such as marssonina blotch, bitter rot, white rot, sooty blotch and flyspeck, and the several insect pests such as apple leaf-curling aphid, woolly apple aphid, oriental fruit moth and peach fruit moth on the almost certified organic or non-chemical pest control orchards. About 10 and 18 environmental-friendly materials were used to control diseases and insect or mite pests respectively. But, lime sulfur and bordeaux mixture to diseases and machine oil, plant oil mixed with egg yolk, and pheromone mating disruptions to insect pests were effective to control under the adequate conditions. At present, it is extremely difficult to produce organic apples in Korea. Growers must consider about and solve so many conditions on the cultivar, weather, local site, marketing and so on, before when they decide to change from conventional or IPM(Integrated Pest Management) to organic or non-chemical pest control orchards.

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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.

Recent Occurrence Status of Two Major Fruit Moths, Oriental Fruit Moth and Peach Fruit Moth in Apple Orchards (사과 주산지 사과원에서 2종 심식나방류의 발생동향)

  • Choi, Kyung-Hee;Lee, Soon-Won;Lee, Dong-Hyuk;Kim, Dong-A;Kim, Soon-Kyung
    • Korean journal of applied entomology
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    • v.47 no.1
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    • pp.17-22
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    • 2008
  • This survey was conducted from 1992 to 2005 in the major apple producing districts in southern part of South Korea including $4{\sim}8$ cities, to know the occurrence and damage level of two major pests, Carposina sasakii and Grapholita molesta that attack apple fruit. The fruit damage by G. molesta during the harvest period ranged from 0.02 to 1.64%. A tendency of higher damage of G. molesta was observed after 1997 compared with the previous years. The other hand, the fruit damage by C. sasakii was 0.02 to 1.30%, and the damage level was very low with fruit damage of < 0.3% except 1998. The orchard infested with G. molesta was 13 to 71 %, while 12 to 57% with C. sasakii. The rates of orchards where fruit damage by G. molesta was found were higher than those by C. sasakii after 1997. The tendency of fruit damage rates in the orchard where the most fruit damage was found was same with the trend of orchard rates infested with the pests. The maximum damage rate by G. molesta was 20.0% in 2005, while 4.5% by C. sasakii in 1998. The damaged shoot rates by the first generation G. molesta was $0.1{\sim}8.1%$, and it had a positive correlation with the rates of fruit damage during the harvest period. Consequently, it is concluded that G. molesta is dominant species compared with C. sasakii in commercial apple orchards recently.

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 ($10^5$ 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 ${\beta}$-tubulin (${\beta}t$) 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 ${\beta}t2$ (5), respectively. The resulting sequences showed 100% identity with sequences of C. gloeosporioides at KC493156, and the sequence of the ${\beta}$t 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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Analysis of Pesticide Applications on Apple Orchards in Geochang, Korea (거창지역 사과원 농약사용 실태분석)

  • Jang, Il;Kim, Hyang-Mi;Lee, Soon-Won;Choi, Kyung-Hee;Suh, Sang Jae
    • The Korean Journal of Pesticide Science
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    • v.19 no.2
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    • pp.93-100
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    • 2015
  • This study surveyed the selling, buying, usage, selection and spraying frequency of pesticides on apple orchards in Geochang, Gyeongsangnam-do province from 2012 to 2013 and found that the fungicides, insecticides and acaricides were sprayed $13.9{\pm}3.5$, $12.6{\pm}3.2$, and $2.6{\pm}1.3$ times per year, respectively. Fungicides were applied mainly to control for Diplocarpon mali, Colletotrichum gloeosporoides and Alternaria mali, whereas insecticides were sprayed mostly to control Grapholita molesta, Carposina sasakii insects. Dealers sold pesticides without monitoring of the pests in the apple orchards, and also sometimes sold pesticides which are non-registered for apple. Most of the farmers were highly relied on dealers' recommendations to choosing the brand product. Relating on Integrated Pest Management (IPM) on apple orchards in Geochang, residual active ingredient of frequently sprayed fungicides, insecticides, and acaricides were analyzed. Most applications of the fungicides, insecticides and acaricides were well corresponded with FAO's recommendations. For production of safe food and use of pesticides, it is requested to develope control calender and consideration of training program for farmers. The regional characteristics and environmental situation of the farm also should be considered.