Taehyun Chang

Kyungpook National University | KNU

Anthracnose, caused by the Colletotrichum genus, comprises a significant number of plant pathogens and poses a major threat to fruit production worldwide, including South Korea. Colletotrichum species were identified associated with anthracnose in fruits such as apple, persimmon, plum, peach, jujube, walnut, and grape. A polyphasic approach, includ...

Walnut (Juglans regia L.) is known as "hodu" in South Korea. It is cultivated as a cash crop and an ornamental plant across South Korea. Walnut anthracnose is one of the main limiting factors for walnut production. In June 2022, severe anthracnose was observed in several walnut fields in Gimcheon, South Korea. The disease incidence was ~35% and sym...

The tea plant (Camellia sinensis (L.) O. Kuntze) is a popular non-alcoholic beverage crop worldwide. The tea market in South Korea is projected to increase annually by 4.59% (Statista, 2022). Boseong, Hadong, and Jeju Island are the main tea-growing regions in South Korea. Anthracnose is one of the major diseases of tea plants and is responsible fo...

Spotted laurel (Aucuba japonica) is a popular ornamental bush (it has two-colored leaves and red berries) and is used outdoors and indoors for decoration in South Korea. Anthracnose reduces the aesthetic value of spotted laurel leaves. In August 2022, anthracnose symptoms were observed on leaves in a park at Jeju Island, South Korea. Approximately...

In this work, we study a series of tunable flux qubits inductively coupled to a coplanar waveguide resonator fabricated on a sapphire substrate. Each qubit includes an asymmetric superconducting quantum interference device, which is controlled by the application of an external magnetic field and acts as a tunable Josephson junction. The tunability...

Superconducting flux qubits are promising candidates for the physical realization of a scalable quantum processor. Indeed, these circuits may have both a small decoherence rate and a large anharmonicity. These properties enable the application of fast quantum gates with high fidelity and reduce scaling limitations due to frequency crowding. The maj...

Jujube (Ziziphus jujuba) is cultivated across South Korea because of its medicinal and economic value. It is used as a sweetener in jam, tea, and snacks and a garnish in many cuisines. Anthracnose caused by Colletotrichum spp. accounts for huge economic losses for jujube growers. In 2019 and 2020, severe anthracnose was observed in the jujube-growi...

In recent years, leaf blight has been observed on dalae (Allium monanthum) leaves at Seosan and Tehan regions in South Korea. Disease symptoms include necrotic spots, lesions, and blight on leaves. The pathogen responsible for the disease was successfully isolated from symptomatic leaf tissue using standard phytopathological procedures and identifi...

Superconducting flux qubits are promising candidates for the physical realization of a scalable quantum processor. Indeed, these circuits may have both a small decoherence rate and a large anharmonicity. These properties enable the application of fast quantum gates with high fidelity and reduce scaling limitations due to frequency crowding. The maj...

In this work, we study a series of tunable flux qubits inductively coupled to a coplanar waveguide resonator fabricated on a sapphire substrate. Each qubit includes an asymmetric superconducting quantum interference device which is controlled by the application of an external magnetic field and acts as a tunable Josephson junction. The tunability o...

Ovate-leaf Atractylodes (Atractylodes ovata) (OLA) is cultivated across South Korea to fulfil domestic need as a herbal medicine. In June 2021, the rhizomes with soft rot were observed in a commercial farmer field in Mungyeong, South Korea with 25% disease incidence. Initially, watery, black and soft lesion were observed on the rhizomes. Later, abu...

Omija or Schisandra (Schisandra chinensis Baillon) is one of Korea’s most unique fruits and have been used in herbal medicine. It is also used for making cold drinks during summer and hot tea during winter. Among the different diseases, anthracnose poses great threat for omija production as it reduces the yield and market quality of fruits. In Sept...

Ovate-leaf atractylodes (OLA) ( Atractylodes ovata ) is a well-known medicinal plant in Korea; its dried rhizome and root extracts are used in herbal medicine. However, anthracnose is a great challenge to the OLA cultivation in South Korea. Colletotrichum spp. is a major group of plant pathogens responsible for anthracnose on a range of economicall...

Background Crown and root rot is the most important and destructive strawberry diseases in Korea as it causes substantial economic loss. In August 2020, a severe outbreak of crown and root rot on strawberries (Fragaria × ananassa Duch.) was observed in the greenhouse at Sangju, South Korea. Infected plantlets displayed browning rot within the crown...

BackgroundA new species within the genus Alternaria was isolated from the leaf spot of Atractylodes ovata in the Mungyeong and Hwabuk-myeon districts of the Gyeongbuk province of Korea. The leaves showed disease symptoms such as circular or irregular leaf spots and brown to dark brown with gray spots at the center. The leaves also showed that conce...

Coconut (Cocos nucifera L.) is one of the most important fruit trees in Bangladesh. This tree is susceptible to various pathogens. Among them, a fungus was consistently isolated from gray leaf spot symptom in coconut. This study aimed to isolate, characterize, and find the management strategies of the causal fungus of gray leaf spot disease in coco...

Crown and root rot is the most important and destructive strawberry diseases in Korea as it causessubstantial economic loss. In August 2020, a severe outbreak of crown and root rot on strawberries (Fragaria×ananassa Duch.) was observed in the greenhouse at Sangju, South Korea. Infected plantlets displayed browning rot within the crown and root, stu...

In South Korea, ovate-leaf atractylodes (OLA) (Atractylodes ovata) is cultivated for herbal medicine. During May to June 2019, a disease with damping off symptoms on OLA seedlings were observed at three farmer fields in Mungyeong, South Korea. Disease incidence was estimated as approximately 20% based on calculating the proportion of symptomatic se...

The Shine Muscat is a table grape, popular in South Korea for its unique mango-flavor taste. Flyspeck is a disease that is characterized by small, black, and circular specks on the grape cuticle was first observed in several commercial orchards in Sangju, South Korea, in August 2019. Here we identified the causal agent of flyspeck based on an advan...

In May to July 2019, ovate-leaf atractylodes seedling and plant with Damping-off symptoms were observed in farmer field at Sangju and Mungyeong, Korea. Seven fungal isolates have been retrieved from diseased root tissue and identified as Rhizoctonia solani AG-5 based on morphological and molecular characteristics. To the best of our knowledge, this...

Grape (cv. Kyoho) is one of the most popular dessert fruits in South Korea. Anthracnose caused by Colletotrichum species is a common and very destructive disease of grape in the country. In 2019, severe outbreaks of anthracnose was observed in different grape orchards in Gimcheon (36º09´N, 128º00´ E), South Korea. The disease incidence on fruit was...

Ovate-leaf Atractylodes (Atractylodes ovata) is a well-known medicinal plant in Korea, where the dried rhizome and the root extract are used in herbal medicines. In 2019, severe damping-off of ovate-leaf Atractylodes at the early seedling stage was observed in a commercial planting in Sangju, South Korea. Approximately 35% of young seedlings sudden...

Plum pocket caused by the dimorphic ascomycetous fungi, Taphrina spp., results in unsightly malformations and crop loss. In 2016, Japanese plums (Prunus salicina Lindl.) with plum pocket symptoms were found in Gimcheon. Three isolates were collected from symptomatic P. salicina fruits and identified as Taphrina deformans based on morphological char...

Apple fruits with anthracnose symptoms were collected from commercial apple orchards in different regions of the Republic of Korea, and isolations were made on potato dextrose agar to isolate the causal agents. The fungal isolates were identified based on their morphological characteristics, growth rates, and multigene sequences. Nine isolates were...

Peach (Prunus persica L.) is one of the major fruit crops in South Korea, along with apple, persimmon, and Asian pears. Peach anthracnose is a continuing threat to growers and is accountable for enormous economic loss. In July 2018, anthracnose of peach appeared at different peach orchards in Gyeongsangbuk-do region, Korea. The typical anthracnose...

Circular leaf spot, caused by the ascomycetous fungus Plurivorosphaerella nawae (= Mycosphaerella nawae), is the most problematic fungal disease of persimmon worldwide. In Korea, persimmon exposed to P. nawae inoculum (ascospores) from May to August shows visible circular leaf spot disease symptoms from the end of August to early September. It is i...

Anthracnose is one of the major problems for cultivating many crops, including vegetables, fruits, and trees. It is a continual threat for fruits grower worldwide. Colletotrichum fructicola was isolated from Shine Muscat berries showing typical anthracnose symptom in Korea. It was identified as C. fructicola based on morphology, pathological signs...

A total of 24 Colletotrichum isolates were isolated from diseased Japanese plum (Prunus salicina) fruits showing chlorotic regions with whitish-brown sunken necrotic lesions and phylogenetic relationships among the collected Colletotrichum isolates were determined. A subset of 11 isolates was chosen for further taxonomic study based on morphology a...

Dragon fruit (Hylocereus polyrhizus) is a newly introduced, and a promising fruit crop in Bangladesh, which has gained considerable interests due to fruits appealing qualities and characteristics. Recently, a stem canker, a new disease of dragon fruit was observed in 30% of plants at different locations of Bangladesh. Initially, symptoms appeared a...

Strawberry (Fragaria × ananassa) was introduced to Bangladesh in 1996 and has gained remarkable acceptance. However, with the expansion of acreage, anthracnose crown rot (ACR) is posing a challenge to strawberry growers. In March 2016, typical ACR symptoms were observed on cultivar Strawberry Festival in a farmer’s field in Rajshahi District. Sympt...

Circular leaf spot is one of the most serious diseases of persimmons in many areas where the crop is grown. This disease is caused by the fungal species Mycosphaerella nawae Hiura & Ikata. Disease cycle of circular leaf spot of persimmon in terms of seasonal pattern of ascospore dispersal and the disease development based on field survey and ascosp...

Persimmon (Diospyros kaki) fruit production is severely affected by circular leaf spot worldwide. Mycosphaerella nawae causes circular leaf spot of persimmon (CLSP) and can result in leaf spot, defoliation, early fruit maturation, and subsequent softening and abscission. The morphology and phylogenetic position of M. nawae within the family Mycosph...

Fungi are known to utilize transcriptional regulation of genes that encode efflux transporters to detoxify xenobiotics; however, to date it is unknown how fungi transcriptionally regulate and coordinate different phases of detoxification system (phase I, modification; phase II, conjugation; and phase III, secretion). Here we present evidence of an...

Persimmon (Diospyros kaki L. f.) fruit production is severely affected by circular leaf spot worldwide. Mycosphaerella nawae Hiura & Ikata is commonly associated with circular leaf spot of persimmon (CLSP) and can result in leaf spot, defoliation, early fruit maturation, and subsequent softening and abscission. The morphology and phylogenetic posit...

Anthracnose is a major disease of persimmon in the pre- and postharvest phase. Several species of Colletotrichum (Colletotrichum gloeosporioides, C. acutatum, and C. horii) have been reported as causal agents of persimmon anthracnose in South Korea. In this study, a collection of 50 isolates associated with persimmon anthracnose were collected from...

The objective was to examine the antifungal activity of Pinus densiflora extract for the control of turfgrass fungal diseases. Antifungal activities of the various fractions of n-hexane, methylene chloride (Ch), ethyl acetate (EtOAc), and n-butanol from P. densiflora were evaluated against Rhizoctonia solani AG1-1B, R. solani AG2-2IV, Sclerotinia h...

Anthracnose is a major disease of persimmon in the pre-and post-harvest phase. Several species of Colletotrichum (C. gloeosporioides, C. acutatum, and C. horii) have been reported as causal agents of anthracnose disease in persimmons in South Korea. In this study, a collection of 50 isolates associated with persimmon anthracnose were collected from...

Circular leaf spot (CLS) is the most important foliar disease of persimmon worldwide. However, the morphological and molecular characteristics of Mycosphaerella nawae Hiura & Ikata, the causative agent of CLS, have not been well studied. Fifteen strains of M. nawae were isolated from persimmon leaves showing the typical symptoms of CLS in 2016. The...

Due to the high environmental risk of chemical pesticides, biological control of plant diseases with bio-pesticides are highly encouraged and recommended. Chitosan and oligochitosan are the well-known biocontrol agents because of their nontoxic, biodegradable and biocompatible properties. Chitosan is considered the most abundant natural polymer wit...

Sangju, South Korea, is famous worldwide for dried persimmon (gotgam) and contributes 60% to the nation’s total production of persimmon. However, one of the main problems in cultivating persimmon is anthracnose disease, which results in huge economic losses. Colletotrichum species such as Colletotrichum gloeosporioides, C. acutatum, and C. horii ar...

In 2010, disease symptoms, including necrotic lesions on stems and leaves with circular yellow-brown or irregular brown color patches, were observed on cool-season turfgrass at golf courses (OHCC) and the Daegu University research farm in Gyeongbuk, Korea. We isolated the causal agent and identified it as Waitea circinata var. zeae by morphological...

The dicarboximide fungicide class is commonly used to control Sclerotinia homoeocarpa, the causal agent of dollar spot on turfgrass. Despite frequent occurrences of S. homoeocarpa field resistance to iprodione (dicarboximide active ingredient), the genetic mechanisms of iprodione resistance have not been elucidated. In this study, 15 field isolates...

In July 2015, diseased leaves of black chokeberry (Aronia melanocarpa) were observed in Danyang and Gochang, Korea. The symptoms appeared as circular or irregular brown leaf spots, from which Alternaria tenuissima was isolated. The isolates were cultured on potato dextrose agar, and their morphological characteristics were observed under a light mi...

Sclerotinia homoeocarpa (F. T. Bennett) is one of the most economically important pathogens on high-amenity cool-season turfgrasses, where it causes dollar spot. To understand the genetic mechanisms of fungicide resistance, which has become highly prevalent, the whole genomes of two isolates with varied resistance levels to fungicides were sequence...

Organic fertilizer preparation was developed with organic materials to improve growth and qualities of cool-season turfgrass species. Organic fertilizer preparation were contained with essential macronutrient elements and organic matter for growth of cool season turfgrass. Four preparations of organic fertilizers were tested on creeping bentgrass (...

Vegetative compatibility groups (VCGs) are determined for many fungi to test for the ability of fungal isolates to undergo heterokaryon formation. In several fungal plant pathogens, isolates belonging to a VCG have been shown to share significantly higher genetic similarity than those of different VCGs. In this study we sought to examine the relati...

Dollar spot, caused by Sclerotinia homoeocarpa, is a prevalent turfgrass disease, and the fungus exhibits widespread fungicide resistance in North America. In a previous study, an ABC-G trans-porter, ShatrD, was associated with practical field resistance to demethylation inhibitor (DMI) fungicides. Mining of ABC-G trans-porters, also known as pleio...

The antifungal potential of essential oil and ethanolic leaf extracts of Lonicera japonica Thunb. was evaluated for controlling the growth of dermatophytes. The oil (1,000 ppm) and extracts (1,500 ppm) of L. japonica revealed 55.1–70.3 % and 40.1–65.5 % antidermatophytic effect against Microsporum canis KCTC 6348, 6349, 6591, Trichophyton rubrum KC...

Four preparations of liquid turfgrass fertilizers were tested cool season turfgrasses during fall season. The preparations of PS-A, PS-B, PH-C and PH-D for commercial products were contained with essential nutrient elements, seaweed extract, amino acids, and humus substance. Growth and quality of creeping bentgrass (Agrostis palustris Huds cv. Penn...

The Rhizoctonia blight causing by Rhizoctonia spp. is an important disease of turfgrass, requiring fungicide application to maintain acceptable conditions for turfgrass good qualities in the golf course. The experiment was conducted to determine the mean 50% effective concentration inhibiting mycelial growth () value of to flutolanil, pyraclostrobi...

Creeping bentgrass (Agrostis stolonifera, allotetraploid 2n = 4x = 28) is one of the major cool-season turfgrasses. It is widely used on golf courses due to its tolerance to low mowing and aggressive growth habit. In this study, we investigated genome relationships of creeping bentgrass relative to the Triticeae (a consensus map of Triticum aestivu...

Pythium blight occurred by Pythium aphanidermatum on chewing fescue cv. "Jamestowm II" from early June, 2010 and 2011 at the test field in Daegu University in Gyeongbuk Province, Korea. Disease symptoms on the turfgrass were leaf blights dying from the leaf tip and root rot, which appeared patches of brown to dark brown color or gray brown color in...

Brown patch caused by Rhizoctonia solani AG-1 IB occurred on Kentucky bluegrass during late May through early October 2010 at golf course in Gyeongbuk Province, Korea. Disease symptoms on the turfgrass for spring season were leaf blights dying from the leaf tip, which appeared patches of brown color in the field. However, it appeared patches of dar...

In response of fungicides for control of gray snow mold, isolates of Typhula incarnata were collected from three golf courses in 2012 Yongpyeong, Korea and tested for sensitivity to propiconazole, tebuconazole and azoxystrobin fungicides. Four discriminatory concentrations were used to detect in vitro sensitivity of 50 isolates. Mean 50% effective...

Potato late blight caused by Phytophthora infestans Cooke is one of the major diseases in the cultivation of potatoes in Korea. Effect of chitosan preparations (SH-1 and SH-2) was evaluated on the inhibition of mycelial growth of P. infestans, and protective activity using detached potato leaf assay both in vivo and in the field test. SH-1 and SH-2...

Dollar spot, caused by Sclerotinia homoeocarpa, is a prevalent turfgrass disease on North American golf courses and sterol demethylation inhibitor (DMI) fungicides are commonly used for disease control. Fungicide resistance to the benzimidazole, dicarboximide and DMI classes has been confirmed in S. homoeocarpa, however resistance has not been conf...

Soil microbial community and soil physiological parameters were investigated by analyzing phospholipid fatty acids extracted from the soils amended with chitosan powder and solution in a cucumber greenhouse. The soils were sampled at 90, 160, 200 days after treatment. Identified fatty acids were analyzed with principal component (PC) analysis. Chit...

Pink snow mold, caused by Microdochium nivale, is a major disease on cool season turfgrasses in golf courses in northern Unites States. The relative susceptibility of 17 commercial cultivars of three bentgrass species (creeping, colonial and velvet bentgrass) to Microdochium nivale and the aggressiveness of M. nivale eight isolates obtained from in...

Grape fruit quality can be deteriorated with leaf chlorosis caused by magnesium (Mg) deficiency during fruit coloring season in several grapevine varieties. The occurrence of leaf chlorosis and soil Mg states for four grapevine varieties (Campbell Early, Muscat bailey A (MBA), Sheridan, and Kyoho) in the vineyards of Gyeongsan and Youngcheon were s...

Chitosan has an antifungal activity and is widely used for control of various plant disease and plants growth in the field in Korea. Disease control efficacy of two preparations (SH-1, SH-2) of mixtures of high and low (chitooligosaccharide) molecular weight chitosan compounds against tomato leaf mold caused by Fulvia fulva was investigated under p...

Soil environmental conditions can affect nutrient availability during growth stage of tree fruit. We investigated the cause of disorderd fruit by the influence of soil chemical properties in orchard soil, composition of mineral nutrient in leaves and fruit to occur physiological disorderd fruit at four locations (Ulsan, Gyeongju, Pyeongtaek, Ansung...

Chang, S. W., Chang, T. H., Abler, R. A. B., and Jung, G. 2007. Variation in bentgrass suscepti- bility to Typhula incarnata and in isolate aggressiveness under controlled environment condi- tions. Plant Dis. 91:446-452. Typhula incarnata, the causal agent of gray snow mold, is an important winter pathogen of turfgrasses in the northern United Stat...

To evaluate the effectiveness of the foliar spray of calcium on "Baekdo" peach fruit, we carried out experiments in the orchards. The sprays were applied with CaCl_2\;(Ca:\;400mg.kg^{-1})\;and\;CaCl_2 with adjuvants (amino acid, 2g.kg^{-1}; phytic acid, 2ml.kg^{-1} and wood vinegar, 2ml.kg^{-1}) for four times from June 12 through July 4 at weekly...

Speckled snow mold, caused by Typhula ishikariensis, is one of the most important Typhula snow molds in subarctic zones of the Northern Hemisphere. Nine isolates of three T. ishikariensis varieties (var. ishikariensis, var. canadensis, and var. idahoensis) isolated from infected turfgrasses on golf course fairways throughout Wisconsin were evaluate...

Dollar spot caused by Sclerotinia homoeocarpa F.T. Bennett is a major disease of turfgrass throughout the world. Current control strategies depend heavily on fungicide application. Host resistance is an alternate management strategy, but a thorough understanding of the pathogen and host interaction is required to utilize it successfully. Seventy-ni...

Fungicides including keroxym-methyl (strobilurin fungicide), fenarimol and trifulmizole (DMI, boscalid (anilide) and metrafenone (benzophenone) were evaluated for preventive and curative efficacies against powdery mildew on oriental melon. The fungicides were applied preventatively at 7 days, 3 days and 3 hours before inoculation. Curative applicat...

To control Phytophthora blight of red pepper biologically caused by Phytophthora capsici, we developed Trichoderma harzianum DYMC for commercial product. DYMC was storage at room temperature and was investigated their population every 3 months for 1 year. For investigating the dynamic population of T. harzianum in the pot soils, we applied powder a...

Creeping bentgrass (Agrostis stolonifera L.) is one of the most adapted bentgrass species for use on golf course fairways and putting greens because of its high tolerance to low mowing height. It is a highly outcrossing allotetraploid species (2n=4x=28, A(2) and A(3) subgenomes). The first linkage map in this species is reported herein, and it was...

An restriction fragment length polymorphism (RFLP)-based genetic map of ryegrass (Lolium) was constructed for comparative mapping with other Poaceae species using heterologous anchor probes. The genetic map contained 120 RFLP markers from cDNA clones of barley (Hordeum vulgare L.), oat (Avena sativa L.), and rice (Oryza sativa L.), covering 664 cM...

In vitro experiments, several fungicides including prochloraz, tebuconazole, fluazinam, fludioxonil, and iminoctadine-triacetate showed more than 85% inhibition of mycelial growth of Pestalotiopsis theae (SP-3). Dichlofluanid and chlorothalonil inhibited mycelial growth at the rate of 10 and 33%, however benomyl did not inhibit mycelial growth of t...

Control effects of phosphorous acid were investigated on Phytophthora blight of red pepper plants in greenhouse and field. In vitro test, the mycelial growth of Phytophthora capsici was inhibited by the phosphorous acid more than 97% at 1,000 and 10,000 a.i./mL in the liquid and solid culture, respectively. At concentration of 10 a.i./mL of phospho...

An actinomycetes strain which produced chitinase, urease, and antifungal substances to Monilinia fructicola was isolated from peaches mummified by Monilinia fructicola. The strain TH-04 was identified as Streptomyces sp. based on cultural and morphological characteristics, cell wall diaminopimelic acid, and sugar patterns of whole-cell extracts. St...

Fungicide-resistant isolates of Monilinia fructicola grew readily on media amended with 0.1, 1.0, 10, 100 and a.i./ml of carendazim, benomyl, or thiophanate-methyl. However, sensitive isolates did not grow on media amended even with a.i./ml of carbendazim, a.i./ml of benomyl or thiophanate-methyl. The fitness compositions including mycelial growth...

In this study, we evaluated the genetic relationships of fourty seven Pestalotiopsis theae isolates collected from diseased sweet persimon in various places in southern part of Korea using RAPD (Randomly Amplified Polymorphic DNAs) method. As a result of the amplification, eight primers showed total of 86 bands ranging from 0.3 Kb to 3.2 Kb. Among...