• Mycobiology
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• v.51 no.4
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• pp.195-209
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• 2023

The seed borne disease such as bakanae is difficult to control. Crop yield loss caused by bakanae depending on the regions and varieties grown, ranging from 3.0% to 95.4%. Bakanae is an important disease of rice worldwide and the pathogen was identified as Fusarium fujikuroi Nirenberg (teleomorph: Gibberella fujikuroi Sawada). Currently, four Fusaria (F. fujikuroi, F. proliferatum, F. verticillioides and F. andiyazi) belonging to F. fujikuroi species complex are generally known as the pathogens of bakanae. The infection occurs through both seed and soil-borne transmission. When infection occurs during the heading stage, rice seeds become contaminated. Molecular detection of pathogens of bakanae is important because identification based on morphological and biological characters could lead to incorrect species designation and time-consuming. Seed disinfection has been studied for a long time in Korea for the management of the bakanae disease of rice. As seed disinfectants have been studied to control bakanae, resistance studies to chemicals have been also conducted. Presently biological control and resistant varieties are not widely used. The detection of this pathogen is critical for seed certification and for preventing field infections. In South Korea, bakanae is designated as a regulated pathogen. To provide highly qualified rice seeds to farms, Korea Seed & Variety Service (KSVS) has been producing and distributing certified rice seeds for producing healthy rice in fields. Therefore, the objective of the study is to summarize the recent progress in molecular identification, fungicide resistance, and the management strategy of bakanae.

• Mycobiology
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• v.46 no.3
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• pp.283-286
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• 2018

Fusarium graminearum causes the devastating plant disease Fusarium head blight and produces mycotoxins on small cultivated grains. To investigate the timeframe of F. graminearum infection during rice cultivation, a spore suspension of F. graminearum was applied to the rice cultivars Dongjin 1 and Nampyeongbyeo before and after the heading stage. The disease incidence rate was the highest (50%) directly after heading, when the greatest number of flowers were present, while only 10% of the rice infected 30 days after heading showed symptoms. To understand the mechanism of infection, an F. graminearum strain expressing green fluorescent protein (GFP) was inoculated, and the resulting infections were visually examined. Spores were found in all areas between the glume and inner seed, with the largest amount of GFP detected in the aleurone layer. When the inner part of the rice seed was infected, the pathogen was mainly observed in the embryo. These results suggest that F. graminearum migrates from the anthers to the ovaries and into the seeds during the flowering stage of rice. This study will contribute to uncovering the infection process of this pathogen in rice.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.119.2-120
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• 2003

Seed-borne fungal pathogens on rice seeds were investigated in order to evaluate their effect on rice grain quality. Rice seeds of two cultivars, Ilmibyeo and Daesanbyeo were collected from 27 areas of Korea and the fungal parasites on seeds were isolated by using a blotter method. Isolation frequency and number of species were varied from collection areas of seed samples. A total 13 species of fungi were identified from the seeds. Among them, Altemana alternata was the most frequent over the country. Bipoiaris oryzae most commonly from Gyeongbuk and Jeonbuk, Alternaria padwickii from Jeonbuk, and Nigrospora oryzae from Choongnam. However Bipolaris. oryzae, Alternaria padwickii, and Nigrospora oryzae were the most frequently isolated fungi from Gyeongbuk and Jeonbuk, and Chungnam, respectively. B. oryzae, A. alternata, A. padwickii, and N. oryzae were dominants on Ilmibyeo showing 10.3％, 10.2％, 5.2％, and 5.2％ infection rate, respectively. While, N. oryzae, A alternata, and Cladosporium sp. were most frequently isolated fungi from Deasanbyeo revealing 15.1％, 9.6％, and 7.5％ infection rate, respectively. These fungi inhabiting on hulls or endosperms of rice seed might be considered as potential factors decreasing rice grain quality. Further investigation of the fungi on grain rice quality are undergoing.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.91.1-91
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• 2003

Bakanae disease, caused by Gibberella fujikuroi (anamorph Fusarium moniliforme J. Sheldon), a typical seed-borne disease of rice occurs from nursery to paddy fields. Consequently, chemical seed disinfectants is the most efficient control method. Several seed treatment methods with various fungicides were attempted to inhibit disease. Spray and 24 hrs immersion of seeds using prochloraz emulsion reduced disease infection and the control value were 99.3 and 100％, respectively. In contrast, dressing to wet seeds thiophanate-methyl＋thiram wp and benomyl＋thiram wp reduced disease infection more effectively than 24 hrs immersion of seeds. However, dressing of carpropamid+imidacloprid＋fludioxonil wp to wet seeds did not reduced disease as well as wettable liquid of fludioxonil. The results suggest that the bakanae disease might be disinfected effectively by 24 hrs immersion of seeds in prochloraz emulsion and seed dressing of fungicides.

• The Korean Journal of Mycology
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• v.13 no.2
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• pp.99-103
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• 1985

F. roseum "Graminearum" and F. moniliforme were isolated from hulls of seeds collected from fields. F. roseum "Graminearum" was isolated from brown rice of all the varieties tested. F. moniliforme was isolated from Nagdongbyeo, Seomjinbyeo, Sinsunchalbyeo, Milyang 23, Baegyangbyeo and Samnambyeo. F. moniliforme was isolated from the most of the seeds damaged by sparrow and it formed sporodochia of this fungus. Five species including F. moniliforme were isolated from plant hopper collected from paddy fields in September. To select seed a disinfectant, twelve fungicides were tested and P242 was one of the best effective fungicidetested. After seed treatment with the fungicide, F. moniliforme was not isolated from hulls but was frequently isolated from brown rices.

• Korean journal of applied entomology
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• v.23 no.2 s.59
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• pp.126-131
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• 1984

Twenty one fungi were detected from 26 rice seed samples obtained from Yeongnam Crop Experiment Station, Honam Crop Experiment Station, Chungnam Provincial Office of Rural Development and farmers of Chungnam Province. Gerlachia oryzae was one of frequently detected fungi with $1.0\~45.0\%$ of detection ratio from 22 rice seed samples. The deep-freezing method was selected as the most suitable for routine seed health testing when the blotter method, deep-freezing method and agar plate method were evaluated for efficiency of detecting seed-borne G. oryzae from rice seeds. Our data obtained by seed component plating technique suggested that G. oryzae was present not only on chaff, in endosperm and in seed coat, but also in the embryo. Seed-borne G. oryzae caused seed rot, seedling blight and symptom of brownish discoloration on coleoptile primary and 2nd leaf when the infected seeds were sown in agar of test tube or in soil.

• The Plant Pathology Journal
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• v.31 no.4
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• pp.334-342
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• 2015

Two fumonisin-nonproducing strains of Fusarium verticillioides and their fumonisin producing progenitors were tested for aggressiveness toward maize, sorghum, rice, and beetroot seedlings grown under greenhouse conditions. None of the plants showed obvious disease symptoms after root dip inoculation. Fungal biomass was determined by species-specific real-time PCR. No significant (P = 0.05) differences in systemic colonization were detected between the wild type strains and mutants not producing fumonisins. F. verticillioides was not detected in any of the non-inoculated control plants. The fungus grew from roots to the first two internodes/leaves of maize, rice and beet regardless of fumonisin production. The systemic growth of F. verticillioides in sorghum was limited. The results showed that fumonisin production was not required for the infection of roots of maize, rice and beet by F. verticillioides.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.91.2-92
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• 2003

In order to elucidate influence of nutritional status on rice brown spot caused by Cochliobolus miyabeanus, rice cultivation soils and rice straws were collected from paddy fields where ice brown spot occurred severely, moderately, a little and none respectively. Rice plant materials were analyzed to measure inorganic nutrients in rice straws and rice seeds. Analysis of chemical properties of rice paddy soil showed that EC and contents of available phosphate, cation and silicic acid in soil with severe infections were lower than those in healthy soil. This result suggests that amount and holding capacity of nutrient contents in soils collected from paddy field with infection of C. miyabeanus are relatively low compared to those in soils collected from healthy paddy field. Analysis of inorganic nutrients in rice straws showed that amount of macronutrient elements such as silicic acids, available phosphate and total nitrogen, and micronutrients such as copper, iron and zinc in rice straws from paddy field with infection were lower than those in healthy soil. Especially amount of iron and silicic acid were very low in rice straws from paddy field soils with infection Amount of inorganic nutrients such as iron and zinc in rice seeds was the same trend as those of rice straws. These results showed that one of major factors affecting rice brown spot was amount of nutrient contents in soil and rice straw.

• Animal cells and systems
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• v.10 no.1
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• pp.21-25
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• 2006

In the present study, Dravya-an organic compound used for seed treatment along with the common fungicides to test its compatibility in the management of Alternaria padwickii in paddy. Dravya (a sea weed extract) was found highly compatible with fungicides like Bavistin and Dithane M-45. Incidence of Alternaria padwickii and Bipolaris oryzae was also reduced to a greater extent in the paddy seed samples of Dravya treatment. On the other hand, it also enhanced the seed germination and seedling vigour. Seedlings of treated samples also showed enhanced activity of peroxidase upon challenge inoculation with Alternaria padwickii. The enzyme activity in the seedlings challenged with the pathogen was two fold more over control. The suppression in disease incidence in growing plants indicated the promising effect of Dravya and Dithane M-45 under green- house conditions.

• The Korean Journal of Mycology
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• v.13 no.1
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• pp.23-26
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• 1985

Percentage of Bakanae infection of rice seedlings grown in nursery box was higher than rice seedlings grown in protected semi-irrigated nursery regardless of seed treatment. Rice seedlings grown in nursery box had higher Bakanae symptom ratio than that of the rice seedlings grown in protected semi-irrigated nursery in the paddy field conditions after transplanting. Grain yield of rice transplanted from nursery box was lower than that of the rice in protected semi-irrigated nursery.