• The Korean Journal of Mycology
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• v.50 no.1
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• pp.41-46
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• 2022

Gastrodia elata infected with root rot disease was collected from cultivated G. elata fields in Gimcheon, Korea, in 2018. G. elata tuber surfaces exhibited root rot disease symptoms of dark-grey lesions and white fungal mycelial growth. The fungus was isolated from symptomatic tubers and cultured. Based on morphological characteristics and molecular analysis of the internal transcribed spacer region of ribosomal DNA and translation elongation factor 1-alpha, the isolated fungus was Fusarium oxysporum. This is the first report of root rot caused by F. oxysporum on G. elata tubers in Korea.

• The Plant Pathology Journal
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• v.18 no.4
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• pp.225-227
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• 2002

Moth orchid plants with yellowing blight and root rot symptoms were collected, and a total of 54 isolates of Fusarium spp. was obtained from roots and leaf bases of the diseased plants. The isolates were identified based on their morphological characteristics. Out of the 54 isolates of Fusarium spp., 42 isolates were identified as F. solani, 5 isolates as F. oxysporum, and 7 as F. proliferatum. Isolates of the three Fusarium spp. were tested for pathogenicity to moth orchid plants by artificial inoculation. All the Fusarium spp. induced root rot of the host plants. The symptoms progressed up to the basal part of the leaves, which later caused yellowing blight. The symptoms induced on the plants by artificial inoculation with the Fusarium spp. isolates were similar to those observed in greenhouses. The present study reveals that F. oxysporum, F. proliferatum, and F. solani cause root rot of moth orchid, and that F. solani is the main pathogen of the disease.

• Mycobiology
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• v.42 no.1
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• pp.66-72
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• 2014

Roselle (Hibiscus sabdariffa L.) family Malvaceae is an important crop used in food, cosmetics and pharmaceutics industries. Roselle is cultivated mainly in Upper Egypt (Qena and Aswan governorates) producing 94% of total production. Root rot disease of roselle is one of the most important diseases that attack both seedlings and adult plants causing serious losses in crop productivity and quality. The main objective of the present study is to identify and characterize pathogens associated with root rot and wilt symptoms of roselle in Qena, Upper Egypt and evaluate their pathogenicity under greenhouse and field condition. Fusarium oxysporum, Macrophomina phaseolina, Fusarium solani, Fusarium equiseti and Fusarium semitectum were isolated from the natural root rot diseases in roselle. All isolated fungi were morphologically characterized and varied in their pathogenic potentialities. They could attack roselle plants causing damping-off and root rot/wilt diseases in different pathogenicity tests. The highest pathogenicity was caused by F. oxysporum and M. phaseolina followed by F. solani. The least pathogenic fungi were F. equiseti followed by F. semitectum. It obviously noted that Baladi roselle cultivar was more susceptible to infection with all tested fungi than Sobhia 17 under greenhouse and field conditions. This is the first report of fungal pathogens causing root rot and vascular wilt in roselle in Upper Egypt.

• The Korean Journal of Mycology
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• v.51 no.1
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• pp.51-56
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• 2023

Dendropanax trifidus belonging to the family Araliaceae, is a warm-temperate evergreen tree distributed in Jeju Island, Bogil Island, Geomun Island, Geoje Island, Wando, and Haenam in Korea. In June 2021, a root rot disease in which branches of Dendropanax trifidus seedlings turned brown and shrunk was discovered at the seedling cultivation facility in Naju-si, Republic of Korea. To identify the root rot fungus, three strains were isolated from the diseased tissues of seedlings and their mycological characteristics were investigated on potato dextrose agar. In addition, a molecular phylogenetic analysis was performed using sequences of the internal transcribed spacer (ITS) region and translation elongation factor 1-α (EF1-α) gene. The fungus was identified as Fusarium oxysporum. For pathogenicity test, the roots of seedlings were immersed in the conidia suspension of the strains and planted. After 20 days inoculation, root rot and browning symptoms were confirmed in the inoculated plants. This is the first report of F. oxysporum on D. trifidus in Korea.

• The Plant Pathology Journal
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• v.39 no.6
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• pp.575-583
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• 2023

Fusarium root rot is an increasingly severe problem in soybean cultivation. Although several Fusarium species have been reported to infect soybean roots in Heilongjiang province, their frequency and aggressiveness have not been systematically quantified in the region. This study aimed to investigate the diversity and distribution of Fusarium species that cause soybean root rot in Heilongjiang province over two years. A total of 485 isolates belonging to nine Fusarium species were identified, with F. oxysporum and F. solani being the most prevalent. Pot experiments were conducted to examine the relative aggressiveness of different Fusarium species on soybean roots, revealing that F. oxysporum and F. solani were the most aggressive pathogens, causing the most severe root rot symptoms. The study also assessed the susceptibility of different soybean cultivars to Fusarium root rot caused by F. oxysporum and F. solani. The results indicated that the soybean cultivar DN51 exhibited the most resistance to both pathogens, indicating that it may possess genetic traits that make it less susceptible to Fusarium root rot. These findings provide valuable insights into the diversity and distribution of Fusarium species that cause soybean root rot and could facilitate the development of effective management strategies for this disease.

• The Plant Pathology Journal
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• v.29 no.4
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• pp.440-445
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• 2013

Balloon flower (Platycodon grandiflorum) is a kind of mountain herbs whose roots have restorative properties and the cultivating acreage of balloon flower has been steadily increasing in Korea. More frequent rain and high amount of rainfalls as a result of climate changes predisposed balloon flower to the outbreaks of root rot at high-density cultivation area in recent years. Root crowns were usually discolored into brown to blackish brown at first and the infected plants showed slight wilting symptom at early infection stage. Severely infected roots were entirely rotted and whole plants eventually died at late infection stage. The overall disease severities of root rot of balloon flower were quite variable according to the surveyed fields in Jeonnam, Gyeongnam and Jeju Provinces, which ranged from 0.1% to 40%. The root rot occurred more severely at the paddy or clay soils than the sandy soils and their severities were much higher at lowland than upland in the same localty. The disease increased with aging of the balloon flower. The causal fungi were identified as Fusarium solani and F. oxysporum on the basis of their mycological characteristics. The optimum temperature ranges of their mycelial growths was found to be $24^{\circ}C$. The pathogenic characters of F. solani and F. oxysporum treated by artificial wounding inoculation on healthy roots of balloon flower revealed that F. solani was more virulent than F. oxysporum. This study identified the causal agents of root rot of balloon flower as Fusarium solani and F. oxysporum, probably for the first time.

• Microbiology and Biotechnology Letters
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• v.41 no.1
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• pp.70-78
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• 2013

Rhizoctonia solani and Fusarium oxysporum cause yield losses in numerous economically important crops. To develop a bio-control agent, cell free extracellular compounds (ECs) of 5 bacterial strains Burkholdria sp. L1, Pseudomonas sp. L4, Pseudomonas chlororaphis VN391, Bacillus subtilis VN21 and Enterobacter sp. VN99 from Vietnamese fields, which reduced levels of R. solani root rot in lettuces and F. oxysporum root rot in tomatoes, were investigated. In a growth chamber, ECs of all antagonists markedly enhanced the biomass of lettuces (10 to 14.1%) and tomatoes (11.38 to 13.88%). In greenhouses, the disease's severity on both crops treated with ECs of the antagonists was reduced significantly and biomass losses in the plants decreased markedly. The reduction level of R. solani root rot in lettuces was 75, 66.7, 50, and 16.7% by ECs of strains L1, L4, VN21 and VN391, respectively. The biomass of lettuces increased markedly by 29.13%, 21.67%, and 23.4% by ECs of strains L1, L4 and VN21, respectively. Similarly, the reduction levels of F. oxysporum root rot in tomatoes was 76.3, 75, 41.7 and 25% by ECs of strain L1, L4, VN21 and VN391, respectively, and the biomass was significantly enhanced by 14.42, 12.7 and 13%, respectively. The ECs of strain L1 exhibited the most effective bio-control agents to suppress R. solani and F. oxysporum.

• Research in Plant Disease
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• v.13 no.1
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• pp.6-14
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• 2007

Root and basal stem rot disease occurred on moth orchid (Phalaenopsis spp.), Pung-nan (Neofinetia falcata) and Nadopung-nan (Aerides japonicum) grown in the farmers' greenhouses located in Namyangju Kyonggi province, Korea during 2005 to 2006. Wilting symptoms occurred on these orchard plants at initial stage and the infected plant leaves turned yellow to red. The discolored leaves were fallen down to lead to eventual death of the entire plant. A total of 59 isolates of Fusarium spp. was obtained from roots and leaf bases of the diseased plants. The cultural and morphological characteristics of isolated Fusairum spp. were identified as Fusarium oxysporum, F. proliferatum and F. solani. F. oxysporum and F. proliferatum were isolated from all these orchard plants but F. solani was isolated only from Phalaenopsis spp. Pathogenicity of the three Fusarium spp. was confirmed by artificial inoculation. Although F. oxysporum, F. proliferatum and F. solani cusing root rot disease in Phalaenopsis spp. have been reported in Korea, the pathogens in N. falcata and A. japonicum were not reported yet. Therefore, this is the first report on the root and stem rot of N. falcata and A. japonicum caused by F. oxysporum and F. proliferatum in Korea.

• The Plant Pathology Journal
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• v.18 no.3
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• pp.156-160
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• 2002

Cymbidium orchids with blight and rot symptoms were collected, and a total of 63 isolates of Fusarium app. was obtained from pseudobulbs, roots, and leaves of the diseased plants. The isolates were identified based on their morphological characteristics. Out of the 63 isolates of Fusatium sup., 51 isolates were identified as F. oxysporum, 10 isolates as F. solani, and the rest as F. proliferatum. F. oxysporum was isolated from all the Cymbidium spp., while F. solani and F. proliferatum were isolated only from Cymbidium ensifolium and C. ginatum, respectively. Isolates of the three Fusarium spp. were tested for pathogenicity to their hosts by artificial inoculation. The strongly pathogenic isolates of Fusarium spp. induced severe dry rot of pseudobulbs and roots of the host plants. The symptoms progressed up to the basal part of the leaves, which later caused blight of the entire plant. The dry root symptoms induced on the plants by artificial inoculation with the isolates of Fusarium app. were similar to those observed in the growers'greenhouses. This is the first report of dry rot of Cymbidium spp. caused by F. oxysporum, F. solani, and F. proliferatum in Korea.

• Mycobiology
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• v.32 no.1
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• pp.42-46
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• 2004

Five fungicides such as rovral, bavistin, cupravit, dithane M-45 and thiovit were tested against conidial germination of Fusarium oxysporum. Dithane M-45 was the most effective against the fungus. Rests of the fungicides were more or less effective in the inhibition of conidial germination after $5{\sim}30$ minutes immersion in $500{\sim}2500$ ppm concentration. Five plant extracts(leaf extracts of Ocimum sanctum, Lantana camera, Calotropis procera, Azadirachta indica and Vinca rosea) found to be more or less effective against the fungus. 'Dhup' somke have good inhibitory effect on conidial germination of F. oxysporum.