• Korean Journal Plant Pathology
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• v.10 no.4
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• pp.325-332
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• 1994

In order to find out formulation and effect of soil amendment on Fusarium wilt of sesame caused by Fusarium oxysporum f. sp. vasinfectum, the study was conducted during the last two years of 1992 to 1993. Among 14 chemicals (1%, w/w) added to soil including CaO individually, Al2(SO4)3, Alum, and CaO suppressed mycelial growth and conidial germination of F.oxysporum f. sp. vasinfectum. CaCl2 suppressed mycelial growth only, while glycerine, KCl, K2 HPO4, and triple superphosphate suppressed conidial germination. Suppression rate was ranged from 21 to 100% on mycelial growth. The 8 chemicals were finally selected. Among the 4 organic compounds, composted pine bark showed definite suppression on mycelial growth and conidial germination of the fungus, whereas milled alfalfa leaves was only effective on conidial germination of Fusarium wilt pathogen. The antagonist Trichoderma harzianum grew well in the soil medium amended with the composted pine bark and chemicals mixture (CPM) amendment (1%, w/w) and suppressed mycelial growth of the fungus effectively. In pot test, Fusarium wilt of sesame was completely controlled by CPM amendment.

• The Korean Journal of Mycology
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• v.19 no.3
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• pp.231-237
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• 1991

This study was conducted in order to find out biological control of sesame wilt and blight caused by Fusarium of oxysporum f. sp. vasinfectum and Phytophthora nicotianae var. parasitica by using Streptomyces spp. Two sesame pathogens, Fusarium oxysporum f. sp. vasinfectum and Phytophthora nicotianae var. parasitica were purely isolated from diseased sesame plants of the field. Streptomyces species were isolated from 72 soil samples collected from red pepper and sesame uplands in Chungbuk and selected as antagonists according to the results of dual culture. The selected Streptomyces isolates such as St-11 and St-20 were confirmed their antagonistic effect through mycelial inhibition zone and inhibitory effects on the mycelial growth of the pathogens by culture filterate of the antagonists. Inhibitory effects on the conidial germination of Fusarium oxysporum vasinfectum and Phytophthora nicotianae parasitica by the antagonists were also tested in addition to mycelial Iysis. The antagonists St-11 and St-20 showed inhibitory effect on growth of sesame seedlings after seeds soaked in the suspension. Effect of soil inoculation with antagonist St-11 showed 40 to 78 percent of control effect for two diseases in comparison with control under greenhouse.

• Korean journal of applied entomology
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• v.2
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• pp.16-21
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• 1963

The present study was undertaken to investigate the effects of different nitrogen source and rate on the growth of Fusarium oxysporum f. vasinfectum which is known to be a noticeable fungus causing the wilt disease of both sesame and cotton in Korea. From the results of this study, It was known that different N source and rate markedly affect the growth of Fusarium oxyspsrum f. vasinfectum Among four N sourses were used in this study, nitrate-N and urea-N were appropriate N source for the growth of fungus. Above all, nitrate N was the best N source because it is utilized in more extensive range of concentration in comparison with the other N source by the fungus, On the other hand, ammonia-N is of little avail for the growth of the fungus because of the formation of unusual colonies with wavy margin and bead-like mycelial cells in addition to marked reduction of mycelial growth and B sporulation of the fungus irrespective of concentration. Judging from the formation of such an abnormal colony and bead-like mycelial cell which is known to be a characteristic of 'staling-type' growth of fungi, the effect of ammonia-N on the growth of Fusarium oxysporum f. vasinfectum is similar to that of phenoxy componnds on some other fungi previously investigated by some workers. Ammonium and nitrate also was not considered to be an appropriate source for the growth of the fungus because of the formation of colonies with slight wavy margin and appreciable reduction of mycelial growth and sporulation in higher concentration than 50meq. , although much or less masking of the irregularity of colony occurs. Therefore, ammonia N alone or any other N combined with ammonia N is of little avail for the growth of Fusarium oxysporum f. vasinfectum.

• Korean journal of applied entomology
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• v.1
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• pp.3-10
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• 1962

1) The purpose of the present study is to investigate the effects of culture filtrates of Fusarium oxysporum f. vasinfectum which is known to produce fusaric acid (wilt toxin) on the germination of sesame seeds and the growth of sesame seedlings. 2) Culture filtrates of Fusarium oxysporum 1. vasinfectum used in this study strongly or weakly inhibited the germination and bring about necrosis accompanying black discoloration of sesame seeds. 3) Varietal difference of sesame in the germination response on the culture filtrates of Fnsarium oxysporum f. vasinfectum is not shown in this study. 4) This study reveals that differential five strains of Fnsarium oxysoprum f. vasinfectum used in this study differ greatly in the toxicity of culture filtrates inhibiting the germination of sesame seeds. 5) In the seedling bed added with culture filtrates of Fnsarium oxysporum f. vasinfectum, the growth of shoot as well as root system of sesame seedlings are notably inhibited and necrotic black discoloration appear on both shoot and root system. But in the seedling beds added with weaker concentration of culture filtrates $/(10\%)$ the growth of shoot is slightly promoted. 6) In culture of sesame seedlings with Knop's solution containing 1 to 3 per cent culture filtrates, the growth of shoot as well as root system are slightly retarded" and till the time of development of the third leaves the whole stem and leaf petiole tissue are weakened so that they become thread like accompanying brown discoloration, interveinal light brown area appear in the second leaves, and the third leaves curl from both sides towards the middle with necrotic brown discoloration, especially symptoms of injury on the third leaves are nearly similar that of the leaves of wilted sesame in the field. 7) A pararell relationship is not found between toxicity of culture filtrates and pathogenicity of five differential strains of Fnsarium oxysporum f. vasinfectum used in this study.

• The Korean Journal of Mycology
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• v.16 no.3
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• pp.157-161
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• 1988

The vegetative nuclear divisions in hyphae and chromosome numbers were studied with the aid of Giemsa-HCl techniques from 10 strains of Fusarium oxysporum. The entire nuclear division process occurred within an intact nuclear envelope like other fungus. The results confirmed that 2 strains(F. oxysporum S Hongchun D2, F. oxysporum S Jinyang 4) were n=4; 3 strains(F. oxysporum f. sp. lini KFCC 32585, F. oxysporum f. sp. melongenae KFCC 34743 and F. oxysporum f. sp. raphani) n=5; 2 strains(F. oxysporum f. sp. vasinfectum, and F. oxysporum f. sp. mori KFCC 34742) n=6; 3 strains(F. oxysporum f. sp. cucumerium, F. oxysporum f. sp.niveum, and F. oxysporum f. sp. pisi) n=7.

• Korean journal of applied entomology
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• v.1
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• pp.42-46
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• 1962

1) The purpcse of the present study is to investigate the effects of culture filtrates of Fuarsium oxysporum f. vasinfectum which is known to produce wilt toxin (fusaric acid) on the germination of host plants (sesame, cotton) and non-host plants (wheat, rice). 2) The experiment on the germination of sesame, cotton, wheat and rice seeds in the seed beds separately added with culture filtr ates of 10 differential strains of Fusarium oxysporom f. vasinfectum demonstrated that culture filtrates of most strains of the fungus inhibit or retard the germination of seeds of 4 plants used in this study while those of a few strains do not give notable influence on the germination of seeds of those plants. a) Culture filtrates of strain 201 of the fungus strongly inhibited the germination of seeds of those plants in nearly same degree, but culture filtrates of the other strains, 281, 321, etc., showed remarkable differences in the toxicity inhibiting or retarding the germination of the seeds of those plants. b) In general, sesame seeds are greatly susceptible, wheat and cotton seeds are moderately susceptible and rice seeds are resistant to the toxicity of culture filtrates of the fungus. 3) In the soil containing a number of differential strains of Fusarium oxysporum f. vasinfectum, the germination of seeds and also the growth of seedlings of non-host plants are possibly checked by the toxic substance, fusaric acid produced by the fungus.

• The Korean Journal of Mycology
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• v.20 no.1
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• pp.65-71
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• 1992

The two isolates of Streptomyces antagonistic to Phytophthora nicotianae var. parasitica and Fusarium oxysporum f. sp. vasinfectum were identified as based on the morphological, cultural and physiological characteristics on various culture media. Spore chains of St-11 isolate was rectus-flexibilis(RF), whereas the other isolate, St-20, was shown rectinaculum-apertum(RA). Spore surface of St-11 isolate was smooth, while St-20 was spiny. Aerial mycelia of the two isolates were all gray color and growing conditions on media were good as a whole. Any soluble pigment was not shown in cultivation of the two isolates. Stoll isolate showed negative response on starch hydrolysis and gelation liquefaction, whereas St-20 isolate was positive on starch hydrolysis and a negative on gelatin reaction. Stoll isolate was identified as Streptomyces bikiniensis and St-20 Streptomyces echinoruber, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.1
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• pp.78-83
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• 1982

Seedling blight of sesame (Sesamum indicum L.) is one of the most serious diseases in Korea. This study was performed to control seedling blight in the field where sesame has been cultured for 4 years of Industrial Crop Division at the Crop Experiment Station. The pathogenic fungi of seedling blight which is known Fusarium oxysporum f. vasinfectium and Rhizoctonia solani was inoculated to the wheat media and it was spreaded on the experimental field in the concentration of 109 of wheat media mixed with 10g of fine soil. Seed sterilization was the most effective method for seedling blight control for two year experiment. Seed sterilant Benlate-T was highly effective for con trolling seedling blight with infection rate of 4% and yield of 40.7kg per 10a comparing to the control with infection rate of 96% and grain yield of 6.4kg per l0a, the other chemicals, Busan 30, Vitathiram, Captan showed good effect to control seedling blight, but less effect to the Benlate-T. The spraying treatments on leaf surface 25 days after sowing were not effective to seedling blight.

• Korean journal of applied entomology
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• v.24 no.3 s.64
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• pp.123-127
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• 1985

Incidence of the Fusarium wilt caused by F. oxysporum f. sp. vasinfectum of sesame (var. Kwangsan) was remarkably influenced by seeding date and mean air temperature in the field of two or three year's continuous cropping with sesame in 1983 and 1985. Sesame were seeded on six different dates from April 20 to July 5. Air temperature was checked daily at the meteorological station near the experimental field. Low($16{\sim}20^{\circ}C$) and high temperature($20{\sim}25^{\circ}C$) periods were provisionally devided, based on every ten-day mean daily temperature during field experiment for last ten years, which corresponded to before and after June 15 in Jinju, Gyeong-nam. Infection rates were 83.7%, 68.2% and 59.4% in the plants grown for 55 days (seeding date: April 20), 40 days(May 5) and 25 days(May 20) under low temperature. On the other hand, infection rates were below 3% in those plots seeded during high temperature period. The longer the growth period exposed to low temperature, the higher was infection rates. It is interesting to note that 40 days old seedling or older are prone to severe infection compared to the younger ones, in higher temperature of $20{\sim}25^{\circ}C$. Therefore, seedlings in vegetative growth stage are less prone to infection than these in reproductive growth stage. The result showed that air temperature during sesame growth was one of the most important factor affecting the incidence of Fusarium wilt. This suggested that sesame crop, which is of tropical origin, has been predisposed to Fusarium wilt, when the plants were exposed to low temperature of $16{\sim}20^{\circ}C$.