• Journal of Food Hygiene and Safety
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• v.7 no.4
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• pp.157-160
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• 1992

The essential oils of Aritemisia princeps var. orientalis (wonnwood) were tested against the standard cultures &cherichia coli, Bacillus subtilis, Pleurotus oststreatus. Fusarium soiani, Aspergillus niduians. Escherichia coli was not susceptible to the wonnwood essential oil but the growth of Bacillus subtilis, Aspergillus niduians, Fusarium solani and Pleurotus ostreatus was severely inhibited by essential oil. The growth of Bacillus subtilis in 1O~100 ppm was a tenth of the control. The wonnwood essential oil also exhibited strong inhibited of the growth of tested fungi. The growth of Pleurotus ostreatus was fully stopped at 1,000 ppm concentration.

• Mycobiology
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• v.30 no.2
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• pp.96-101
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• 2002

Four pathogenic fungal isolates belonging to different genera including Alternaria, Fusarium and Curvularia were isolated from selected diseased weeds growing in the fields in Dakahalia district. The inoculum of these pathogenic fungi specific to weeds were cultured, standardized and formulated as alginate pellets containing mycelium plus culture filtrate. These mycoherbicides were evaluated for disease severity(DS). Maximum DS was obtained with the alginate pellets of mycelium filtrate Fusarium solani. Physiological changes of the treated weed were determined 5 aiid 10 days after treatments. As compared to the healthy weeds, all mycoherbicide formulations significantly decreased the amount of photosynthetic pigments and subsequently soluble and insoluble sugars in the infected weeds. The mycoherbicide formulation of F. solani had the greatest effect on lowering to the abovementioned amount in the leaves of Chenopodium murale. Generally, treatment of weed leaves with the specific mycoherbicide led to a highly significant increase in total phenol content when compared to the healthy control weed. C. murale infected with the mycoherbicide formulation of F. solani had higher levels of phenolic compounds than those other treated weeds particularly after 10 days of inoculation.

• The Plant Pathology Journal
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• v.17 no.1
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• pp.52-56
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• 2001

This study was undertaken to separate and identify antifungla substances produced by Gilocladium virens G1, a biocontrol agent used for the control of plant diseases caused by Rhizoctonea solani. The culture of G. virens G1 effectively inhibited the growth of R. solani, Colletotrichum gloeosporioides, and Phytophthora capsici, but less that of Fusarium oxysporum. The n-hexane extract of the G. virens culture, which was used for the purification of responsible substances, strongly inhibited R. solani and C. gloeosporioides, but not P. capsici, although the n-butanol extract was effective on all of the pathogens tested. An antifungal substance was purified using the n-hexane extract by Silica gel column chromatography and HPLC. The substance was examined for purity by HPLC and for nature by UV spectrometry, which differed from known antibiotic compounds such as gliotoxin, viridin and gliovirin. The antifungal substance was very liphophilic based on its solvent-solubility and Rf values on TLC, and more inhibitory to C. gloeosporioides than other fungal pathogens tested.

• The Korean Journal of Pesticide Science
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• v.19 no.4
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• pp.424-427
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• 2015

Damping-off is a critical disease on ginseng seedling, which caused by the fungal pathogen Rhizoctonia solani. The disease has been prevented by tolclofos-methyl for the last 20 years. However, the tolclofos-methyl usually detected on the harvested roots of 6-year-old ginseng. Herein, we tried to select an alternative pesticide which not only must be safe but also efficiently inhibits the fungal pathogen. Four fungicides (fludioxonil, flutolanil, pencycuron, and thifluzamide) were applied to their inhibition efficacy against the pathogen. In in vitro test, fludioxonil treatment showed 80% inhibition activity for 25 days. Thifluzamide and flutolanil showed the activity for 10 days. Pencycuron showed for 1 days. In addition, the fludioxonil was more effective to control the pathogen comparing to other three fungicides in field. The incidence of damping-off was reduced to 71% by fludioxonil treatment. The level of the fungicide residue in seedling was 0.44 mg/kg, which value will be a negligible level in final products after 5 years. Consequently, the fludioxonil is a conceivable alternative for tolclofos-methyl to cope with R. solani.

• Research in Plant Disease
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• v.15 no.1
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• pp.54-56
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• 2009

Stem rot of perennial statice (Limonium sinuatum) was observed in Un bong, Jeonbuk from 2006 to 2007. Affected plants were randomly distributed in the greenhouses and infection rate was more than 10%. Stem and leaf of statice at soil line were dried and turned brown, initially. As the disease became severe, other stem parts and crowns were turned dark brown and then sunken. The fungal isolates were showed initially white aerial mycelium and turned brown with age. They produced few sclerotia which small, irregularly shaped with pinpoint sized. Mycelia were branched at $90^{\circ}$ angles and multinucleate in one cell. The pathogenicity of causal organism was proved according to Koch's postulates. The causal fungus of stem rot was identified as Rhizoctonia solani based on the cultural and morphological characteristics. This is the first report on stem rot of statice by R. solani in Korea.

• 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.

• Korean Journal Plant Pathology
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• v.11 no.1
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• pp.1-8
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• 1995

Alternaria alternata and A. solani were identified from 130 Alternaria isolates obtained from red pepper fruits, and three species including A. alternata, A. sesami and A. sesamicola were detected from 150 isolates from sesame seeds. Among the 4 Alternaria species, A. alternata was the predominant fungus from both plants, having incidence of 95.4% in red pepper and 56.0% in sesame. Of the total 280 isolates, cultures on autoclaved rice of 75 isolates were tested for toxicity to 21-day-old virgin female rats. Out of 50 isolates of A. alternata, 17 were lethal to rats, inducing congestion and hemorrhage of stomach and intestine and kidney enlargement, and 8 caused lack of weight gain or weight loss. The other 25 isolates of A. alternat and all the isolates of A. sesami, A. sesamicola and A. solani, showed no significant indication of toxicity. Production of mycotoxins in the rice cultures of the above 75 isolates belonging to 4 species was analyzed. Alternaria cultures were extracted with methanol and purified by using solvent partition, thin-layer chromatography, and high performance liquid chromatography. Of the four species tested, all produced alternariol (AOH) and alternariol monomethyl ether (AME), three (A. alternata, A. sesami and A. sesamicola) produced alternuene (ALT) and altertoxin-I (ATX-I), and only A. alternata produced tenuazonic acid (TA). TA was produced by all of the highly toxic (lethal to rats) isolates of A. alternata, but not by any nontoxic isolates.

• The Plant Pathology Journal
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• v.21 no.3
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• pp.275-282
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• 2005

A chitinolytic bacterium, Chromobacterium sp. strain C-61, was found strongly antagonistic to Rhizoctonia solani, a causal agent of damping-off of eggplant. In this study, the biocontrol activity and enzymatic characteristics of strain C-61 were compared with its four Tn5 insertion mutants (C61-A, -B, -C, and -D) that had lower chitinolytic ability. The chitinase activity of a 2-day old culture was about $76\%,\;49\%\;and\;6\%$ level in C61-A, C61-B and in C61-C, respectively, compared with that of strain C-61. The $\beta-N-acetylhexosaminidase$(Nahase) activity was little detected in strain C-61 but increased largely in C-61A, C61-B and C61-C. Activities of chitinase and Nahase appeared to be negatively correlated in these strains. Another mutant, C-61D, produced no detectable extracellular chitinase and Nahase. The in vitro and in vivo biocontrol activities of strain C-61 and its mutants were closely related to their ability to produce chitinase but not Nahase. No significant differences in population densities between strain C-61 and its mutants were observed in soil around eggplant roots. The results of SDS-PAGE and isoelectrofocusing showed that a major chitinase of strain C-61 is 54-kDa with pI of approximately 8.5. This study provides evidence that the biocontrol activity of Chromobacterium sp. strain C-61 against Rhizoctonia solani depends on the ability to produce chitinase with molecular weight of 54-kDa and pI of 8.5.

• The Plant Pathology Journal
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• v.37 no.4
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• pp.315-328
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• 2021

Fusarium and Rhizoctonia genera are important pathogens of many field crops worldwide. They are constantly evolving and expanding their host range. Selecting resistant cultivars is an effective strategy to break their infection cycles. To this end, we screened a collection of Medicago truncatula accessions against Fusarium oxysporum, Fusarium solani, and Rhizoctonia solani strains isolated from different plant species. Despite the small collection, a biodiversity in the disease response of M. truncatula accessions ranging from resistant phenotypes to highly susceptible ones was observed. A17 showed relative resistance to all fungal strains with the lowest disease incidence and ratings while TN1.11 was among the susceptible accessions. As an initiation of the characterization of resistance mechanisms, the antioxidant enzymes' activities, at the early stages of infections, were compared between these contrasting accessions. Our results showed an increment of the antioxidant activities within A17 plants in leaves and roots. We also analyzed the responses of a population of recombinant inbred lines derived from the crossing of A17 and TN1.11 to the infection with the same fungal strains. The broad-sense heritability of measured traits ranged from 0.87 to 0.95, from 0.72 to 0.96, and from 0.14 to 0.85 under control, F. oxysporum, and R. solani conditions, respectively. This high estimated heritability underlines the importance of further molecular analysis of the observed resistance to identify selection markers that could be incorporated into a breeding program and thus improving soil-borne pathogens resistance in crops.

• Mycobiology
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• v.28 no.4
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• pp.185-189
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• 2000

The antifungal activity of methanolic extracts of Centella asiatica and Andrographis paniculata leaves was observed against fourteen fungi, viz., Alternaria alternata, A. brassicae, A. brassicicola, A. solani, A. tenuissima, Cercospora blumae, Curvularia lunata, C. penniseti, and Drechslera monoceras, D. oryzae, D. turitica, Fusarium albizziae and F. udum. Different concentrations of the methanolic extract (1000, 2000, 3000, 5000, 7000, 10000ppm) were used. The effect of mixed leaf extract (1500 ppm of C. asiatica + 1500 ppm of A. paniculata) and its 1:2 ad 1:4 dilutions were also studied. The individual extracts of both the plants showed significant inhibitory effect on spore germination of all the fungi tested. F. udum, F. albizzae, D. oryzae, D. turtica, and D. monoceras were particularly sensitive to these extracts. In general, the extract of C. asiatica showed a higher inhibitory effect in all concentrations against all the fungi as compared to A. paniculata, except for A. brassicae A. solani, D. oryzae, D. penniseti and Curvularia sp. The inhibitory effect of extracts increased when they were used in combination with or without dilutions against A. brassicicola, A. solani A. brassicae, A. alternata, A. tenussima, C. blumae, C. lunata, C. penniseti and Curvularia species. Higher efficacy of active ingredient of these extracts under field condition is envisaged against plant pathogens.