• Mycobiology
• /
• v.39 no.2
• /
• pp.113-117
• /
• 2011

A laboratory experiment was conducted to study the induction of constricting rings and test predation of Dactylaria brochopaga isolates against second stage juveniles (J2s) of Meloidogyne graminicola. Among the five fungal isolates, isolate D showed the greatest number of predatory rings and, consequently, trapped the maximum number of M. graminicola J2s in dual cultures. Another pot experiment was conducted to study the effect of D. brochopaga (isolate D) on the management of wheat root-knot disease. Applying a mass culture (10 g/pot) and a spore suspension of the fungus with and without cow dung manure to soil infested with 2,000 M. graminicola juveniles significantly improved plant height, root length, weights of shoots, roots, panicles and grains per hill compared to those in the control. Moreover, the fungus significantly reduced the number of root-knots, the number of egg masses, juveniles, and females per hill compared to those in the control. Bio-efficacy of the fungus was heightened when the mass culture and a spore suspensions were used in combination with cow dung manure to improve the plant growth parameters and reduce the number of root-knot and reproductive factors. Further investigations should be conducted to identify the impact of this fungus in the field.

• Proceedings of the Korean Society of Plant Pathology Conference
• /
• 2003.10a
• /
• pp.104.1-104
• /
• 2003

To screen for potential biocontrol agents against postharvest disease of garlics caused by Penicillium hirsutum, a total of 933 isolates (432 fungi and 501 bacteria) were isolated from the rhizoshere or rhizoplane of garlics. Among them, Pantoea agglomerans isolate 59-4 (Pa 59-4) was selected for a potential biocontrol agent by in vivo wounded garlic bulb assay, When the spore suspension (10$\^$5/ spores/$m\ell$) of Penicillium hirsutum was co-inoculated with spore or cell suspension of each fungal or bacterial isolate on wounded garlics, the isolate highly suppressed disease development. Soaking garlic bulbs in the suspension of Pa 59-4 significantly reduced garlic decay from p. hirsutum. However, Pa 59-4 did not inhibit the mycelial growth of P. hirsutum in dual-culture with P. hirsutum on Tryptic soy agar. In order to elucidate mode of action of Pa 59-4 nutrient competition between Pa 59-4 and P. hirsutum was investigated using tissue culture plates with cylinder inserts containing defusing membrane reported by Janisiewicz et al. The results showed that Pa 59-4 effectively suppressed spore germination and mycelial growth of blue mold in the low concentration (0.5％) of garlic juice, but did not suppress those of blue mold in the higher concentration (5％) of garlic juice. This result suggests that the mechanism in biocontrol of garlic blue mold by Pa 59-4 may involve in nutrient competition with P. hirsutum on garlic bulbs.

• Korean journal of applied entomology
• /
• v.12 no.1
• /
• pp.23-27
• /
• 1973

In an effort to find effective inoculation method of Fusarium nivale, this experiment was conducted. The results obtained are summarized as follows: (1) Distilled water-spore suspension of this fungus was inoculated on rice seedling and the result showed that negligible disease symptoms were observed when the inoculated plants were placed in a moist chamber for one day, whereas considerable symptoms were indicated when kept for two days. (2) After giving physical wounds by wind or wooden stick to the rice seedling, distilled water-spore suspenion was sprayed on them and considerable diseased spots were formed. (3) Sufficient disease occurrence was due to the addition of $1\%$ rice leaf extract, glucose, polypeptone, and yeast extract solution to the spore suspension. (4) In distilled water, spore germination was poor, while in nutrient added solution good germination rate as well as anastomosis was found. (5) A new rice variety Tong-il turned out to be more susceptible to Fusarium nivale than Pung-kwang.

• Research in Plant Disease
• /
• v.15 no.3
• /
• pp.217-221
• /
• 2009

Fludioxonil is derived from the antifungal compound pyrrolnitrin produced by Pseudomonas pyrrocinia and classified as a reduced-risk fungicide by the US EPA. The efficacy of fludioxonil for the control of lettuce gray mold caused by Botrytis cinerea was evaluated under several conditions such as growth stages of host, inoculum concentrations, and amounts of potato dextrose broth (PDB) included in spore suspension of B. cinerea. At 4-leaf stage of lettuce plants, fludioxonil applied at 2 ${\mu}g$/ml was more effective for the control of gray mold than at 5- and 6-leaf stages. However, fludioxonil at more than 10 ${\mu}g$/ml provided similar control activity in all growth stages of lettuce tested. The fungicide (10 and 50 ${\mu}g$/ml) also gave excellent control of gray mold on lettuce seedlings inoculated with spore suspensions of B. cinerea ($2.5{\times}10^5$ to $2{\times}10^6$ spores/ml). But, control efficacy of fludioxonil (2 ${\mu}g$/ml) was negatively correlated with inoculum concentration. Addition of PDB in spore suspension of B. cinerea resulted in higher disease severity than non-treated control. By inoculating spore suspension including 0.5% PDB, the fungicide gave the most control activity on the disease, followed by 1% and 2% PDB. The results suggest that fludioxonil has potential to control gray mold of lettuce, but the fungicide at a concentration having moderate activity may represent low control efficacy on the disease under some conditions.

• Korean Journal of Environmental Agriculture
• /
• v.30 no.4
• /
• pp.453-458
• /
• 2011

BACKGROUND: Coleosporium plectranthi, an obligate parasite, which is responsible for the rust disease of Perilla frutescens, a plant in Korea, commonly known as Perilla. All rusts are obligate parasites, meaning that they require a living host to complete their life cycle. They generally do not kill the host plant but can severely reduce growth and yield. Food and feed spoilage fungi cause great economic losses worldwide. It is estimated that between 5 and 10% of the world food production is wasted due to fungal deterioration. Rust disease of Perilla is highly frequent and is widely spread in Korea. The present study was designed to investigate a novel media for the urediniospore germination in vitro and anti-rust activity as well as GC-MS analysis of oak pyroligneous liquor. METHOD AND RESULTS: Urediniospores were collected from the infected leaf of Perilla. Spore suspension was made and the suspension was inoculated in the 2% water agar media with proper humidity, then they were incubated at $26^{\circ}C$ for 56 hrs. The GC-MS analysis of the oak pyroligneous liquor was also done to check the chemical composition. GC-MS analysis of the wood vinegar was found 15 compounds, among them o-mthoxyphenol (25.93%), 2,6-dimethoxyphenol (16.06%), 4-methylenecyclohexanone (10.69%), 2,3-dihydroxytoluene (7.84%), levoglucosane (6.14%) and propanoic acid (5.32%) were the major components. Different concentration of the oak pyroligneous liquor was used, and spore inhibition was recorded on the basis of spore counting. The best results were noted at the concentration of 50% solution where 31.8% spores were inhibited. CONCLUSION: On the basis of the chemical composition of the oak pyroligneous liquor and the activity recorded we can use it as an anti-rust agent.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.11 no.2
• /
• pp.101-108
• /
• 2008

This study attempted to develop the technology by gaseous ozone for decontaminating building affected by a model of biological weapon agent(Bacillus subtilis spores) instead of Bacillus anthracis spore. The use of ozone is attractive method from a practical point of view of decontamination procedure since it has strong oxidation power but no residue after application. We examined the disinfection efficiency of gaseous ozone to Bacillus subtilis spores which suspension was sprayed on different material surfaces and dried. Three different types of gaseous ozone was applied : dry ozone, dry ozone with humidified air, and water bubbled wet ozone. Dry ozone(1500ppm) failed to achieve any significant inactivation for 2hrs. However, six log reduction of B. subtilis spore was achieved within 30min by 1500ppm of water bubbled wet ozone. This result shows the noticeable inactivation efficiency by gaseous ozone compared with previous studies. Good performance by wet ozone was also found for military material surface.(i.e. : gas mask hood, protective garments, army peinted metal surface).

• Microbiology and Biotechnology Letters
• /
• v.23 no.2
• /
• pp.236-242
• /
• 1995

Biological control of soilborne plant pathogens by the addition of antagonistic microorganisms to the soil may offer a practical supplement or alternative to existing disease management strategies that depend heavily on chemical pesticides. Soil amendment with antagonistic microbes was non-effective because of high cost, low efficacy, and inconvenient usage on the treatment course. Therefore, seed coating formulation for the application of biological seed treatments has been being to apply successful disease suppression for many important crops. The objectives of this study were to investigate the optimal condition for the spore production of biocontrol agent Bacillus subtilis YBL-7 and the liquid coating formulation that contained a suspension of a proper aqueous binder, as well as a ground fine solid particulate material. The maximum yield has been obtained from 60 hrs-old culture at 30$\circ$C in spore forming (SF) medium containing 0.8% nutrient broth, 0.05% yeast extract, 10$^{-1}$ M MgCl$^{2}$, 10$^{-4}$ M MnCl$^{2}$, 10$^{-5}$ M dipicolinic acid, and pH 6.5. The optimal condition of dried spore preparation was achieved when cells of B. subtilis YBL-7 was heat-dried with 50$\circ$C for 2 hrs.

• Preventive Nutrition and Food Science
• /
• v.12 no.4
• /
• pp.251-258
• /
• 2007

Thermal resistance and heat activation characteristics of Clostridium botulinum ATCC 25763 spores were evaluated. The effects of nisin and pH on the activation and subsequent germination were also investigated. Spores of C. botulinum were not inactivated by heat treatments up to $92^{\circ}C$ for 2 hr. Heat treatment at $85^{\circ}C$ for 90 min was selected as the optimal activation condition based on monitoring subsequent germination. L-alanine alone or in combination with L-cysteine was not sufficient to germinate the spores of this strain. Tryptone-Peptone- Glucose-Yeast extract (TPGY) broth supplemented with L-alanine was used as a suitable germination medium. Decreasing pH of activation suspension increased the degree of phase darkening, i.e., germination. In addition, the presence of nisin during activation increased the degree of phase darkening. The majority of spore populations were dormant at a pH of less than 2.8, and these populations required heat activation to increase the culturability on TPGY agar medium. However, extended heating in the presence of nisin at pH 2.8 decreased the spore count; however, heat activation was less necessary at pH 3.4, compared at pH 2.8.

• Research in Plant Disease
• /
• v.11 no.1
• /
• pp.43-47
• /
• 2005

To investigate control efficacy of flusulfamide GR (granule) on Chinese cabbage clubroot caused by Plasmodiophora brassicae, experiment was accomplished in field located in Gangneungshi alpine area contaminated by P. brassicae. Flusulfamide GR provided control value of 84.6% and that was statistically significant difference from standard fungicides containing untreated control. To investigate ratio of reduction of resting spore according to fungicide treatment, soil of Chinese cabbage field before and after fungicide treatment were sampled and investigated density of resting spore. Resting spore density was not uniform in soil before fungicide treatment. Therefore, to investigate control efficacy of fungicide against clubroot, investigation on resting spore density was conducted before experiment and reflected in experimental design. Flusulfamide GR and DP (dust powder) provided 64.2% and 63.7% of reduction of resting spore on field soil after fungicide treatments. This result indicated that control efficacy of the fungicides was correlated with reduction of resting spore of P. brassicae. The increasing rate in fresh weight of above-ground part of Chinese cabbage by flusulfamide DP and GR, fluazinam DP and trifloxystrobin SC (suspension concentrate) was 14.3%, 13.0%, 13.8% and 3.8%, respectively. From above result, flusulmide GR have outstanding control efficacy against clubroot of Chinese cabbage and is effectively decreasing of resting spore density in soil.

• Korean Journal Plant Pathology
• /
• v.14 no.4
• /
• pp.325-330
• /
• 1998

On the basis of the fact that the pycnidiospore of Botryosphaeria dothidea, the causal fungus of apple white rot is a typical water borne spore, a method for quantitative analysis of pycnidiospore dispersal from the warts produced on the diseased apple tree stem was developed. The warts on which cracks developed either on or around them were cut off at the base, and shaked in the water for 4hours at 2$0^{\circ}C$, in which condition the maximum number of spores were released. The volume of shaking solution was calculated as 1 ml per one wart. At the end of shaking, Trio, a household detergent was added to the shaking solution to the concentration of 0.1%, and shaked for additional 10 minutes at 35$^{\circ}C$ to take off the spores attached on the glass ware. One milliliter of the spore suspension thus prepared were passed through transparent membrane filter (pore size : 3.0 ${\mu}{\textrm}{m}$), and the spores attached on the filter were counted under a microscope ($\times$200) after staining them with lactophenol supplemented with aniline blue. The results thus obtained were statistically consistent when at least 30 warts were used simultaneously in single shaking. This method can be applicable in the elucidation of ecology of sporulation and spore dispersal, and also in the screening of the sporulation inhibitor which can be used in the control of the disease by reducing the inoculum density.