• Journal of Life Science
• /
• v.11 no.3
• /
• pp.242-247
• /
• 2001

Botrytis cinerea E12 was isolated from the leaves, flowers and fruits of eggplant in the greenhouse in Halrim, Kimhae and Dejeo, Pusan. The leaves infected with the pathogen were appeared initially brown-color, small gray spots at the edge, and finally fall down. The fruit was showed the symptoms of circular or irregular shapes, followed by sunken. When the symptoms were developed, the conidia formed on the surface with gray color. To determine the pathogenicity of B. cinerea E12 against the eggplants, the conidia were suspended with 30% tomato juice, PDB and sterile water, respectively. The result showed that the conidial suspension with 30% tomato juice was highly effective on the pathogenicity as more than 90%. Moreover, the symptoms caused by inoculum were the same as those of wild-type pathogen.

• Korean journal of applied entomology
• /
• v.22 no.4 s.57
• /
• pp.287-292
• /
• 1983

Incubation period of rice neck blast was investigated by injection of conidial suspension of Pyricularia oryzae into young panicles inside the flag leaf sheath at booting stage. Eleven to fifteen days were taken for symptom appearance from the date of injection. About two days were taken from conidia germination until infection occurred, the incubation period was determined as nine to thirteen days for the symptom development of neck blast in rice plants.

• The Plant Pathology Journal
• /
• v.26 no.4
• /
• pp.421-423
• /
• 2010

New sources of barley (Hordeum vulgare L.) resistant to spot blotch, caused by Cochliobolus sativus, are needed to provide effective resistance because of the rapid change pathotype patterns of C. sativus in fields. The purposes of our study were to develop a method to screen barley for resistance to spot blotch disease and then use this methodology to screen barley genotypes for resistance to the major virulent pathotype Pt4 in barley populations in Syria. A transparent tape method, in which a conidial suspension of C. sativus was dropped onto transparent tape and placed, treated-side down, on the second leaf surface of barley plants. Disease symptoms of fungus were easily detected on the leaves covered by the transparent tape after 48h of inoculation. The transparent tape method was repeatable and the disease scores obtained were correlated (r = 0.91, P = 0.001) with those obtained by the seedling assay. This method may be beneficial in various plant pathology breeding programs.

• The Plant Pathology Journal
• /
• v.15 no.5
• /
• pp.308-310
• /
• 1999

A fungus associated with gray blight on tea plant (Camellia sinensis) was identifed as Pestalotiopsis theae based on the mycological characteristics. Mycelial growth on potato dextrose agar and size and shape of conidia of P. theae were similar to those of P. longiseta, but P. theae was different from P. longiseta in the color of three median cells and the number of apical appendages. Artificial inoculation of conidial suspension or mycelial mats on the wounded leaves and shoots of healthy plants induced the same disease, respectively. The Korean native variety was relatively. The Korean native variety was relatively more resistat to P. theae than a Japanese variety‘Yabukita’which has bee recently introduced and planted in large areas of southern parts of Korea. Here, we report the report the first record of gary blight caused by P. theae on tea plant in Korea.

• Microbiology and Biotechnology Letters
• /
• v.18 no.5
• /
• pp.460-465
• /
• 1990

Regeneration of protoplast was effective by preincubating spore suspension containing 30$\mu g$/ml of 2-DG for 4 hours, and CBE medium containing casamino acid, bovine serum albumin, ergosterol and myoinositol was found to be more efficient than any other regeneration medium tested in this experiment. The regeneration frequency was about 30%. Optimal conditions for conidial protoplast fusion were obtained by treatment of protoplasts with 10 mM $CaCl_2$ and 30% polyethylene glycol 4000 (pH 7.5) as fusogenic agent at $37^{\circ}C$ for 10 minutes. The fusion frequency was $8.2\times 10^{-4}$. The higher productivity of enzyme of fusant FWN-56 was achived: 2.3-fold for CMCase, 1.5-fold for avicelase, 1.8-fold for $\beta$-glucosidase and 2.5-fold for xylanase compared to that obtained in two parental strains. The genetic stability of fusant after maintenance on minimal medium for more than 4 weeks was high because segregant rate was below 1%. The conidial DNA content of fusant was 1.4-1.6 times higher than that of the parental strains, The nucleus size of fusants were also higher than that of each parental strains.

• Research in Plant Disease
• /
• v.26 no.3
• /
• pp.190-193
• /
• 2020

In 2014, Anthracnose symptoms were observed on fruit of pumpkin in Gangneung, Gangwon in Korea. The typical symptoms on fruit surfaces were circular lesions, brown, shriveled with salmon-colored spore masses on the spots. A fungal isolate was obtained from symptomatic on fruit and cultured on potato dextrose agar at 25℃. The color of the upper surface of the colony varied from white to gray with occurrence of salmon-colored conidial masses and was red to violet on the underside. The causal fungus of anthracnose isolated from the diseased fruits was identified as Colletotrichum fioriniae based on mycological characteristics and sequences of the internal transcribed spacer, glyceraldehyde-3-phosphate dehydrogenase, chitin synthase-1 gene, histone H3, actin gene, beta-tubulin gene region. Pathogenicity tests of the isolate were performed on pumpkin fruit by both wound and non-wound inoculation with conidial suspension (1×10⁶ conidia/ml) and incubated at 25℃. Lesions were observed on both wounded and non-wounded fruit of pumpkin after 7 days inoculation in only C. fioriniae. The pathogen was re-isolated from the lesions of inoculated fruits. To our knowledge, this is the first report of anthracnose on fruit of pumpkin caused by C. fioriniae in Korea.

• Mycobiology
• /
• v.29 no.1
• /
• pp.19-26
• /
• 2001

Defense mechanisms against anthracnose disease caused by Colletotrichum orbiculare on the leaf surface of cucumber plants after pre-treatment with plant growth promoting rhizobacteria(PGPR), amino salicylic acid(ASA) or C. orbiculare were compared using a fluorescence microscope. Induced systemic resistance was mediated by the pre-inoculation in the root system with PGPR strain Bacillus amylolquefaciens EXTN-1 that showed direct antifungal activity to C. gloeosporioides and C. orbiculare. Also, systemic acquired resistance was triggered by the pre-treatments on the bottom leaves with amino salicylic acid or conidial suspension of C. orbiculare. The protection values on the leaves expressing SAR were higher compared to those expressing ISR. After pre-inoculation with PGPR strains no change of the plants was found in phenotype, while necrosis or hypersensitive reaction(HR) was observed on the leaves of plants pre-treated with ASA or the pathogen. After challenge inoculation, inhibition of fungal growth was observed on the leaves expressing both ISR and SAR. HR was frequently observed at the penetration sites of both resistance-expressing leaves. Appressorium formation was dramatically reduced on the leaves of plants pre-treated with ASA, whereas EXTN-1 did not suppress the appressorium formation. ASA also more strongly inhibited the conidial germination than EXTN-1. Conversely, EXTN-1 significantly increased the frequency of callose formation at the penetration sites, but ASA did not. The defense mechanisms induced by C. orbiculare were similar to those by ASA. Based on these results it is suggested that resistance mechanisms on the leaf surface was different between on the cucumber leaves expressing ISR and SAR, resulting in the different protection values.

• Research in Plant Disease
• /
• v.7 no.3
• /
• pp.134-139
• /
• 2001

Effects of tomato-juice and KH$_2$PO$_4$ as exogenous nutrients on the infection of Botrytis cinerea LVF12 and pathogenicity to tomato were investigated. B. cinerea LVF12, which was previously reported as a casual agent of the gray mold rot of perilla, was used for pathogenesis on tomato leaves. No infection was induced, and no lesion developed on tomato leaves by the conidial suspension of LVF12 when the inoculum was prepared in sterilized water. However, when the conidial suspensions of LVF12 added with various concentrations and conditions of tomato-juice were inoculated on whole tomato plants, the disease was induced readily, Among them, 20% tomato juice with 0.1M KH$_2$PO$_4$ appeared to be the most suitable nutrient to promote high disease incidence on tomato. For the pathogenicity test according to the growing stage of tomato, the mature leaves were more susceptible than seedlings. Symptoms on the infected plants were initial small gray spots at the inoculated area. Later the whole leaves, petioles and stems became gray and eventually fell off, Under high humidity conditions, the diseased leaves and stems were covered with gray hyphae and conidia. All symptoms of infected plants were identical to those in the field conditions.

• The Korean Journal of Pesticide Science
• /
• v.18 no.2
• /
• pp.115-121
• /
• 2014

This study was performed to investigate the effect of conidial density, wetness period and temperature on conidial germination, appressoria formation and disease incidence. While there was not significantly correlated between conidial density and temperature, and conidial germination and appressoria formation, there was a significant correlation between those factors and disease incidence. The longer wetness period was, the higher the ratio of conidial germination, appressoria formation and the disease incidence was. The optimum conidial density, temperature and wetness period was $1{\times}10^6$ conidia $mL^{-1}$, $30^{\circ}C$ and 5 days, respectively. In case the wetness period was more than 5 days, the typical symptom was not found on pepper fruits because of the overgrowth of mycelia. Using this fruit assay method, which the pepper anthracnose pathogens were inoculated by spraying spore suspension on non-wounded or wounded pepper fruits, control effect of three fungicides were evaluated against pepper anthracnose by the protective and/or the curative application. Propineb showed high protective control activity, while it showed curative control activity on unwounded fruits, but did not showed curative control activity on wounded fruits. Tebuconazole, one of curative fungicide, showed higher control activity in non-wound inoculation than wound inoculation. Trifloxystrobin, one of strobilurin group, showed high both protective and control activity against anthracnose. In conclusion, we supposed that the newly developed in vitro pepper fruit assay can be used to evaluate antifungal activity of control agents against pepper anthracnose.

• The Plant Pathology Journal
• /
• v.36 no.4
• /
• pp.335-345
• /
• 2020

Tomato grey mould has been one of the destructive fungal diseases during tomato production. Ten mM of menadione sodium bisulfite (MSB) was applied to tomato plants for eco-friendly control of the grey mould. MSB-reduced tomato grey mould in the 3rd true leaves was prolonged at least 7 days prior to the fungal inoculation of two inoculum densities (2 × 10⁴ and 2 × 10⁵ conidia/ml) of Botrytis cinerea. Protection efficacy was significantly higher in the leaves inoculated with the lower disease pressure of conidial suspension compared to the higher one. MSB-pretreatment was not effective to arrest oxalic acid-triggered necrosis on tomato leaves. Plant cell death and hydrogen peroxide accumulation were restricted in necrotic lesions of the B. cinereainoculated leaves by the MSB-pretreatment. Decreased conidia number and germ-tube elongation of B. cinerea were found at 10 h, and mycelial growth was also impeded at 24 h on the MSB-pretreated leaves. MSB-mediated disease suppressions were found in cotyledons and different positions (1st to 5th) of true leaves inoculated with the lower conidial suspension, but only 1st to 3rd true leaves showed decreases in lesion sizes by the higher inoculum density. Increasing MSB-pretreatment times more efficiently decreased the lesion size by the higher disease pressure. MSB led to inducible expressions of defence-related genes SlPR1a, SlPR1b, SlPIN2, SlACO1, SlChi3, and SlChi9 in tomato leaves prior to B. cinerea infection. These results suggest that MSB pretreatment can be a promising alternative to chemical fungicides for environment-friendly management of tomato grey mould.