• Korean journal of applied entomology
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• v.11 no.1
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• pp.19-23
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• 1972

Apple cankers caused by Valsa mali Miyabe, Botryosphaeria ribis Cross, Phomopsis truncicola Miura, are distributed in the main apple growing areas, Choong Chung Puk Do, Choong Chung Nam Do, and Kyung Sang Puk Do. According to the survey in 1970 that Valid mali is the dominant causal organism among the three in the most severely damaged area. Valsa mali and Botryosphaeria ribis were found in ail 3 provinces, however, Phomopsis truncicola was not found in Choong Chung Nam Do. Especially, Botryosphaeria ribis was most abundant in Chunwon of Choong Chung Nam Do. Effects of chemical control of apple canker caused by Valsa mali were tested both on potato dextrose agar with inhibition zones produced by the fungicides and relative growth of assay fungus of peridermis was treated with tile fungicides. Ifost effective was mercuric and followed by Lime sulfur, Hydroquinone sulfate, in general.

• Research in Plant Disease
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• v.26 no.2
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• pp.61-71
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• 2020

With 32 fungicides, it was examined the inhibitory effects on the mycelial growth of Alternaria dauci KACC42997 causing Alternaria leaf blight of carrot. Showing the results of the agar dilution method, the fungicides belonging to C2, C5, G1, E2, and E3 group were excellent in inhibiting mycelial growth. Protective fungicides belonging to M group, except for iminoctadine tris-albesilate, and pyraclostrobin belonging to C3 group were effective in inhibiting spore germination of pathogens. The fungicides included into C2 group inhibiting succinate dehydrogenase activity and the G1 group inhibiting demethylase activity showed the excellent inhibitory effect on mycelial growth but the inhibitory effect of spore germination was very low. However, fluazinam belonging to C5 group was excellent in inhibiting spore germination as well as mycelial growth. Especially, when 100 ㎍/ml of fluxapyroxad belonging to the C2 group was treated, 47.1% of spore formation was inhibited on the medium. In comparison of the resistance factors of 3 fungicide groups, as G, C, and E group, in populations of A. dauci isolates collected from Gumi, Pyeongchang, and Jeju, resistance factor in the population of Jeju was the lowest. However, two isolates resistant to fludioxonil belonging to E2 group were found in the isolate group of Pyeongchang, and both showed cross-resistance to iprodione and procymidone.

• Journal of Life Science
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• v.25 no.9
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• pp.1036-1042
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• 2015

By using effective sanitizers, early block for transmission of pathogens is the effective way to prevent epidermic outbreaks. Here we developed a chlorine oxide bubbling type of sanitizing tablets and evaluated the disinfectant and sanitization effects. The sanitizers showed 99.999% of sanitization effect for Escherichia coli ATCC 10536 and Staphylococcus aureus ATCC 6538 strains for 5 min±10 sec on 20±1℃ in clean condition by dilution-neutralization method. It reduced more than 5 log₁₀ cfu/ml of a legal permission standard of colony reduction. When a few used socks and underwear soaked for one hour in the 0.1% of the sanitizing tablets, no microorganisms were grown on CHROMagar plates. However, on CHROMagar plates of the no sanitizing tablets treated control, about 6.5×10⁴ cfu/ml of Staphylococcus sp., Klebsiella sp. and Enterococus sp. were grown. Furthermore, the sanitizing tablets killed approximately 1.5x10⁸ cfu/ml of E. coli BL21 in 5 minutes. Therefore, we concluded that the chlorine based bubbling type of sanitizing tablets satisfied the legal standard for the regulation of food and drug safety for disinfectants and sanitizers to pathogens and daily supplies.

• Korean Journal Plant Pathology
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• v.3 no.3
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• pp.217-222
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• 1987

Pathogenicity of nine Rhizoctonia solani isolates of different anastomosis groups (AG) on seed and hypocotyls of red pepper, cucumber, Chinese cabbage and radish varied considerably from nonvirulent to highly virulent. Rhizoctonia solani AG 1 was highly virulent on the above four plant species. AG 2 type 1 was highly virulent on radish and Chinese cabbage, moderately virulent on red pepper, and AG 2 type 2 was avirulent or weakly virulent except red pepper. R. solani AG 5 was moderately virulent on hosts tested. In general, virulence of the R. solani isolates to a given host varied among anastomosis groups, but not within anastomosis groups. Anastomosis groups lacked host specificity. The pathogenicity was stronger in steam-sterilized soil than in non-sterilized field soil, if the inoculated plants were closely related with orginal host from which the pathogen was isolated. On the other hand, pathogen was more virulent in non-sterilized field soil than in steam-sterilized soil, if the inoculated ones were not closely related. Generally, contrary to other soil-brone plant pathogenic fungi, Rhizoctonia isolates tended to be more virulent in non-sterilized field soil than in the same soil which had been steamed. A potential danger of building up propagules of R. solani in southern horticultural area are discussed in terms of cropping system.

• The Korean Journal of Pesticide Science
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• v.14 no.4
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• pp.463-472
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• 2010

It was conducted to investigate the control efficacy of carboxylic acid amide (CAA) fungicides, such as benthiavalicarb, iprovalicarb, dimethomorph and mandipropamid, against pepper Phytophthora blight caused by P. capsid in the laboratory and the field. The fungicides inhibited mycelial growth and direct sporangium germination of P. capsid strongly, while there was no activity of all fungicides against zoospore release from sporangium. In greenhouse test, they showed the good protective and curative effect against pepper Phytophthora blight. Benthiavalicarb applied at $100{\mu}g\;mL^{-1}$ 7 days before inoculation prevented pepper Phytophthora blight by 100%, even though the zoosporangiurn suspension of P. capsid adjusted to not only $5{\times}10^3$ zoosporangia $mL^{-1}$ but also $1{\times}10^5$ zoosporangia $mL^{-1}$ was inoculated by soil-drenching. Except for dimethomorph, the other fungicides showed an excellent control activity over 2 years from 2009 to 2010 in the field test. The control value of dimethomorph applied at $250{\mu}g\;mL^{-1}$ was low, 27.2% in 2009, but that of dimethomorph applied even at $125{\mu}g\;mL^{-1}$ was high, 89.5% in 2010. All the fungicides showed good inhibitory effect on the mycelial growth and the direct germination of zoosporangiurn, and controlled pepper Phytophthora blight preventively and curatively, can be used to establish the spray system for control1ing the pepper disease.

• Applied Biological Chemistry
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• v.49 no.4
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• pp.259-265
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• 2006

Effect of the fungicide mepanipyrim on the resistant and sensitive isolates of Botrytis cinerea was studied in vitro and also tested to control Botrytis rot of strawberry, cucumber and grape in the field. These isolates were selected by relative mycelial growth and spore germination on potato dextrose agar(PDA) incorporated with $100{\mu}g\;a.i./ml$ of benomyl and procymidone, respectively, compared to the unamended PDA. Mycelial growth of the selected resistant isolates was significantly inhibited by mepanipyrim but the inhibition rate was similar to other fungicides belong to benzimidazole or dicarboximide, although spore germination was not inhibited even by the higher concentration of mepanipyrim. When the benomyl and procymidone resistant isolates were inoculated to cucumber leaves, lesion development was significantly inhibited with application of $250{\mu}g\;a.i./ml$ of mepanipyrim but not with that of benomyl and procymidone. In addition, when $250{\mu}g\;a.i./ml$ of mepanipyrim was applied to strawberry, cucumber, and grape in the field, the control of Botrytis rot was significantly different from that of the untreated control(Duncan's multiple range test, p<0.05). The results suggested that mepanipyrim might be an alternative fungicide for the control of benomyl- and procymidone-resistant pathogens of Botrytis rot.

• Weed & Turfgrass Science
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• v.6 no.2
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• pp.151-156
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• 2017

Summer patch is the most serious disease at turfgrass field or golf course established with Kentucky bluegrass during high temperature season in Korea. Nevertheless, chemicals for the summer patch control are not yet registered in Korea. We isolated the pathogens from the turfgrass showing typical summer patch symptoms and identified as Magnaporthiopsis poae by using the internal transcribed spacer ITS1 and ITS4 sequences of rDNA. The inhibition rates of the pathogen were investigated for 10 fungicides. As results, the pathogen growth was suppressed when chemicals concentration increased and negatively correlated with incubation period with the chemicals. In triazole group, all chemicals (metconazole, myclobutanil, propiconazole and tebuconazole) treated showed the inhibition rates by 100%. Thiophanate-methyl showed the next highest inhibition effect against a summer patch pathogen. In strobilurin group, pyraclostrobin was the highest suppression effect compared with azoxystrobin and trifloxystrobin. Inhibition effect of fludioxonil and fluxapyroxad on pathogen was similar to the trifloxystrobin. Based on the results, triazole and carboxamide groups are strongly recommended due to the highest inhibition effect on the summer patch pathogen, Magnaporthiopsis poae.

• Research in Plant Disease
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• v.25 no.4
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• pp.188-195
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• 2019

Among 6 fungicides, fluazinam, which had an excellent inhibitory effect on mycelial growth and spore germination, was also effective in controlling jujube anthracnose in the field. While EC₅₀ values of metconazole and tebuconazole ranged from 0.2 to 0.9 ㎍/ml and from 0.4 to 1.1 ㎍/ml against the mycelial growth, respectively, each inhibitory effect on spore germination was low by 7.4% and 11.1% at 50.0 ㎍/ml. In the field test, they showed the control value of 80.5% and 77.0%, respectively. The protective fungicides, as mancozeb and folpet, which had a low inhibitory effect on the mycelial growth, but had a high inhibitory effect of spore germination, showed excellent disease control activities by 87.6% and 92.0% in the field. Showing a result of resistance monitoring conducted with the isolates of Colletotricum gloeosporioides, the resistance against carbendazim was already generated in the field, but it was thought that there was no resistance to pyraclostrobin, fluazinam and tebuconazole. However, if the resistance factor value of the population of C. gloeosporioides isolates to pyraclostrobin was high by 160.4, the diversity of the response to the fungicide in the population was high, so it should be taken more attention to the resistance management.

• The Korean Journal of Pesticide Science
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• v.14 no.4
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• pp.456-462
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• 2010

Baseline sensitivity to benthiavalicarb, iprovalicarb and dimethomorph included into carboxylic acid amide (CAA) group was evaluated in 180 isolates of Phytophthora capsici over 4 years from 2005 to 2008. $EC_{50}$ (effective concentration inhibiting mycelial growth by 50%) value of benthiavalicarb ranged from $0.015{\mu}g\;mL^{-1}$ to $0.049{\mu}g\;mL^{-1}$ with a mean of $0.033{\mu}g\;mL^{-1}$. The mean values of $EC_{50}$ of iprovalicarb and dimethomorph were 0.411 (0.197 - 0.556) ${\mu}g\;mL^{-1}$ and 0.271 (0.101 - 0.798) ${\mu}g\;mL^{-1}$, respectively. Although there was no increasing tendency in $EC_{50}$of benthiavalicarb and iprovalicarb during 4 years, $EC_{50}$ of dimethomorph was increased gradually by laps of time. There was no cross-resistance between each fungicide used in this study and metalaxyl. Among fungicides included into CAA group, there was a positive correlation between benthiavalicarb and iprovalicarb, and between dimethomorp and mandipropamid.

• Korean journal of applied entomology
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• v.4
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• pp.11-18
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• 1965

In order to investigate the fungicidal activities against various plant pathogenes, diminishing effect of plant transpiration, phytotoxicities, vapor effect and the rate of reduction by ultraviolet rays of phenylmercuric 8-oxyquinolinate(P.M.Q), this experiments were undertaken under various laboratory conditions. 1. Inhibitory activity on the spore germination of this chemical was shown less effective than that of P.M.A..(Table 2, Table 3, Table 4, Table 5 and Table 6) Also, P.M.Q. was resulted a somewhat higher inhibitory activity on the hyphae growth than P.M.A. (Table 7). 2. In the diminishing effect of plant transpiration, 8-hydroxyquinoline sulfate(oxine sulfate) was more strong inhibitory at first than P.M.Q., while, at last, P.M.Q. was more strong inhibitory in comparison with oxine sulfate(Table 8, Fig. 1 and Table 9). 3. P.M.Q. was shown less injury on the germination of rice plant seeds and the emergence of their roots than P.M. A.(Table 10). Injuries was not observed on the rice seedlings and soy-bean seedlings sprayed with 40 ppm of this chemical. 4. P.M.A. had more inhibitory effects on the mycelial growth of phytopathogenes than P.M.Q. on the vapor effect (Table 11, Fig. 2). 5. Biological activity and chemical decomposition rate of P.M.A. were greatly reduced by exposure of this compound to ultraviolet rays. But, P.M.Q. was only slightly affected by similar treatment(Table 12, Fig. 3, Table 13 and Fig. 4). From the above results, this chemical will be a promising fungicide adding fungitoxicities against various phytopatho genes, diminishing effect of plant transpiration and physico-stability.