• Research in Plant Disease
• /
• v.10 no.2
• /
• pp.105-111
• /
• 2004

Mycelial growth and days required for sclerotial formation(DRSF) in vitro, and disease incidence of infected plants in the field were investigated to evaluate disease resistance of nine garlic cultivars against two species of Sclerotium causing garlic white rot. There were differences among mycelial growth and sclerotial formation of two white rot pathogens on different garlic cultivars in vitro. Mycelial growth showed the highest level on the clove of 'Daeseo'. Sclerotia of two white rot pathogen were formed the earliest on the clove of 'Kodang' and the latest on the clove of 'Namdo'. In field trial all of nine garlic cultivars were highly susceptible to Sclerotium cepivorum and cold-type garlics were less susceptible than warm-type garlics. Meanwhile garlic cultivars used showed differences among resistant responses to Sclerotium sp., forming large sclerotia. All of warm-type garlics showed highly susceptible response, but three cold-type garlics, 'Seosan', 'Danyang' and 'Yechon' showed moderate resistant response and 'Euisung' showed resistant response. To evaluate cultivar resistance of garlics quantitatively disease progress curve was transformed as linear regression equation. Among the intercept (early disease incidence) and the slope (disease infection rate) obtained from the transformed equation, final disease incidence, and area under disease progress curve(AUDPC), AUDPC was the most effective to evaluate disease resistance of garlics to both of white rot pathogens. There was little correlation between mycelial growth and sclerotial formation on garlic cloves in vitro, and epidemiological parameters (early disease incidence, final disease incidence, disease infection rate, AUDPC) obtained from the field trial. Mycelial growth of S. cepivorum was positively correlated with final disease incidence and disease infection rate obtained from the field trial, meanwhile DRSF was negatively correlated with the epidemiological parameters.

• The Korean Journal of Mycology
• /
• v.41 no.1
• /
• pp.42-46
• /
• 2013

Burkholderia pyrrocinia CAB08106-4 was parceled out from the Chungnam Agricultural Research and Extension Center, Korea to evaluate the antagonistic activity against garlic white rot caused by Sclerotium cepivorum. The optimum cultural conditions including temperature, pH, enzyme activity, carbon and nitrogen sources were determined. The optimum culture conditions of B. pyrrocinia CAB08106-4 were $286^{\circ}C$, 150 rpm and pH 7. Chitinase only showed activity among several tested enzymes. The highest cell growth was obtained with 1% glucose and 0.1% $(NH_4)_2SO_4$, respectively.

• Proceedings of the Korean Society of Plant Pathology Conference
• /
• 2003.10a
• /
• pp.131.2-132
• /
• 2003

White rot on garlic caused by Sclerotium cepivorum firstly occurred at Goheoung, Jeonnam in 1998. Thereafter, the disease rapidly spread throughout the country except Gangwon and became a major limiting factor for the cultivation of various Allium species such as garlic, onion, and welsh onion. The disease that has not been reported on a wild garlic(Allium monanthum) previously occurred severely at Seosan, Choongnam in 2003. Among cultivation areas in the region, 10.7％ were infected by the disease and the ratio of diseased plant reached up to 55.0％ in some heavily infected fields. Two species of Sclerotium were consistently isolated from infected samples and identified as S. cepivorum or another Sclerotium sp. Averaged size of sclerotium of the former was 455.0x562.2 urn, while the later was 374.4${\times}$347.2$\mu\textrm{m}$. Patogenicity to Allium species and mycological characteristics such as sclerotium size, growth temperature, and microconidia of the fungi were similar to those reported on other Allium species previously. Consequently, the wild garlic is a newly reported host of the two pathogenic fungi in Korea.

• The Korean Journal of Pesticide Science
• /
• v.18 no.1
• /
• pp.21-25
• /
• 2014

Bukholderia pyrrocinia CAB08106-4 has an anti-fungal effect on Garlic White Rot caused by Sclereotium cepivorum and Sclereotium sp. It is environmentally friendly microbial product that prevents and controls a variety of phytopathogens including Garlic White Rot caused by Sclereotium cepivorum and Sclereotium sp. The aim of this study was to assess the environmental toxicity using Cyprinus carpio and Daphnia magna. Bukholderia pyrrocinia CAB08106-4 ($1.0{\times}10^9cfu/mL$) was adminatrated to Cyprinus carpio and Daphnia magna according to the toxicity test guideline for peciticide. $LC_{50}$ of Bukholderia pyrrocinia CAB08106-4 is over $6.67{\times}10^4cfu/mL$ in Cyprinus carpio and Daphnia magna and no adverse effect was observed. Based on these results, we concluded that Bukholderia pyrrocinia CAB08106-4 has no toxiciy for Cyprinus carpio and Daphnia magna.

• The Korean Journal of Pesticide Science
• /
• v.17 no.2
• /
• pp.133-139
• /
• 2013

To investigate the sensitivity of Sclerotium cepivorum causing garlic white rot to 5 fungicides, including prochloraz, tebuconazole, flutolanil, iminoctadine and isoprothiolane, 147 isolates isolated from infected garlics from 2008 to 2009 through a single sclerotium isolation were screened. While each mean value of $EC_{50}$ (effective concentration reducing mycelial growth by 50%) of S. cepivorum isolates collected in 2008 to each fungicide was 0.054, 0.012, 23.189, 0.901, and $21.362{\mu}g\;mL^{-1}$, that of 2009 isolates were 0.030, 0.020, 10.367, 1.684, $33.406{\mu}g\;mL^{-1}$. There was a difference in mean value of $EC_{50}$ of S. cepivorum according to regions isolated. $EC_{50}$ values of S. cepivorum isolated in Goheung to flutolanil and isoprothiolane were 14.468 and $24.653{\mu}g\;mL^{-1}$, respectively, which was lower than those of Seosan and Taeahn. Isolates from Taeahn showed the lowest $EC_{50}$ value to prochloraz as $0.008{\mu}g\;mL^{-1}$. In addition, we could not find any resistant isolates to fungicides tested. The $EC_{50}$ values in this study will be used in a fungicide resistance monitoring program to determine whether shifts in sensitivity to fungicides included into different groups are occurring in S. cepivorum populations.

• The Korean Journal of Mycology
• /
• v.45 no.4
• /
• pp.381-385
• /
• 2017

Sclerotinia rot was observed on Ixeridium dentatum cultivated as a succeeding crop in a garlic field in Seosan-si, Korea during the growing season in 2016 and 2017. Symptoms progressed from the initial irregular, water-soaked spots on main stems to wilting and eventually to plant death. White, cottony mycelia and black, irregular sclerotia formed on the basal stem and on soil surfaces. The optimal temperature of hyphal growth and sclerotia germination were $20^{\circ}C$ and $25^{\circ}C$, respectively. Sequence analysis of the internal transcribed spacer (ITS) regions revealed that the three strains isolated from Ixeridium dentatum are grouped with Sclerotinia sclerotiorum. Three strains were identified as Sclerotinia sclerotiorum based on morphological features, ITS sequence, and pathogenicity test. To the best of our knowledge, this work is the first report of Sclerotinia sclerotiorum causing sclerotinia rot on Ixeridium dentatum in Korea.

• The Plant Pathology Journal
• /
• v.20 no.4
• /
• pp.240-243
• /
• 2004

White rot on Allium crops recently had a high incidence with incrensed cultivating areas of tropical garlic types in Korea. Two types of Sclerotium have known as causal agents that produce different size and shapes of sclerotia in infested fields. Therefore, we developed a new method for isolation of sclerotia from infested field soils that can be used for ecological study of Sclerotium spp. and establishment of control strategy. Soil samples collected from heavily infested fields were evenly mixed and placed on a automatic sieve shaker connected with tap water, After 10 min of shaking, residues on 0.5 mm and 0.25 mm sieves were separately collected and suspended with 70% sugar solution, which method floats sclerotia in aqueous layer, Then, floated fraction was carefully separated and mixed with a same volume of 1% sodium hypochlorite solution to differentiate with organic materials. This method provides a direct count of sclerotia under a dissecting microscopy.

• Microbiology and Biotechnology Letters
• /
• v.42 no.3
• /
• pp.225-231
• /
• 2014

In this study about the optimum conditions for the production of laccase, a polyphenol oxidase involved in lignin degradation, from Marasmius scorodonius, a white-rot fungus garlic mushroom, were determined. Amongst the tested media used for the enzyme's production, YM medium (1% dextrose, 0.5% malt extract, 0.3% yeast extract) allowed for the highest activity of the enzyme. Then, to optimize the culture conditions for laccase activity, the influence of various carbon and nitrogen sources was investigated in YM medium. Among various carbon and nitrogen sources, 1% galactose and 0.4% yeast extract resulted in the highest production of the enzyme, respectively. Enzyme production attained its highest level after cultivation for 15 days at $25^{\circ}C$. Zymogram analysis of the culture supernatant showed two isoenzymatic bands with molecular masses of 60-70 kDa. The optimum pH and temperature for enzyme activity were 3.4 and $75^{\circ}C$, respectively.

• Journal of the Korean earth science society
• /
• v.39 no.5
• /
• pp.419-435
• /
• 2018

The purpose of this study is to understand meteorological and climatological factors that have influence on the garlic product in Seosan and Taean, and to analyze the economic value according to the use of climatical information data for garlic farmers. The climatological characteristics and trends in this area are analyzed using the meteorological data at the Seosan local meteorological agency from 1984 to 2013, the national statistical data for the product of garlic from 1989 to 2013, and the scenario data for climate change (RCP 4.5 and 8.5) for the period from 2001 to 2100. The results are as follows. First, the condition of lower temperature for garlic growth in winter season is satisfied with the mean air temperature. The wind speed are lower and stronger in Seosan and Taean than other garlic area. The suitable condition for the growth of northern type of garlic shows the decreasing trend in the accumulated precipitation in May. However, the area of growing the northern type garlic in the future is likely diminished because mean air temperature, accumulated precipitation, and mean wind speed are strong in the harvest time of garlic. Second, the seedtime of the northern and southern type of garlic using climate change scenarios (RCP 4.5, 8.5) in Seosan and Taean is getting late as time passes. and the harvest time gets faster, which indicates s that the period of garlic cultivation becomes shorter from 50 days to around 90 in the next 100 years. Third, the beginning days of white rot and delia platura of garlic are estimated by applying to the meteorological algorithm using mean air temperature and soil humidity. Especially, the beginning day of white rot garlic is shown to be faster according to the scenarios of RCP 4.5 and RCP 8.5. Fourth, the product of garlic (kg/10a) shows a high correlation with the minimum air temperature of a wintering time, the mean wind speed of a wintering time, the accumulated precipitation of a corpulent time, and the mean relative humidity of corpulent time of garlic. On the other hand, the analysis of garlic product when using the meteorological information data in cultivating garlic in Seosan and Taean reveals that the economic value increases up to 9% in total.

• Journal of Climate Change Research
• /
• v.5 no.1
• /
• pp.47-59
• /
• 2014

This study was conducted to estimate of future productivity for major spicy vegetables by the change of meteorological factors, temperature and precipitation. Based on analysis of meteorological factors, incidence of major disease(phytophthora blight and anthracnose) for hot pepper was over 50% with temperature over $18.3^{\circ}C$ in May and precipitation over 532 mm in July. And the meteorological factors in the August have deeply related to the incidence of virus disease(CMV and BBWV2) for hot pepper, however, both the meteorological factors and the incidence of virus disease showed to the opposite tendency. An analysis of the relevance of the white rot disease and the meteorological factors for garlic, a disease was highly investigated with temperature $15.0^{\circ}C$ to $15.9^{\circ}C$ in April to May. On the onion, higher incidence of white rot was investigated with temperature over $4.0^{\circ}C$ in November to January and precipitation over 40 mm in March. The occurrence of major disease for spicy vegetables and meteorological factors as a result of regression analysis, the optimal cultivation area of peppers and onions will be gradually expanded to the central regions in the near future in Korea.