• Korean Journal Plant Pathology
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• v.10 no.4
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• pp.270-276
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• 1994

Mycelial growth resistant isolates of Botryosphaeria dothidea to benomyl showed 99~79% spore germination on the PSA media supplemented with 200~2,100 $\mu\textrm{g}$/ml of carbendazim and thiophanate-methyl to manifest the high cross-resistance in spore germination. Mycelial growth, 23~9 mm in colony diameter, also manifested the high cross-resistance of mycelial growth together with similarity of spore forming cross-resistance. Benomyl resistant isolates BR1, BR2 and BR3, grew 23~10 mm in colony diameter at 330~3,000 $\mu\textrm{g}$/ml of captafol, captan and oxine-copper showing the high double resistance of mycelial growth and spore formation with minor difference. However, within concentration range of the 3 fungicides tested, germinations of all the tested isolates were completely suppressed to show no double-resistance in the fungal spore germination.

• The Korean Journal of Mycology
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• v.12 no.1
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• pp.1-8
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• 1984

The mycelial growth of some mushrooms was inhibited by benomyl treatment. The $ED_{50}$ of benomyl to that of Pleurotus spp., Agaricus bisporus and Flammulina velutipes was 25ppm, 50ppm and 200ppm, respectively, which indicates the former was the most sensitive to the fungicide. The mycelial growth of mushrooms growing on artificial media amended by benomyl was increased when they were cultured successively 5 times and 10 times on the media. The increasing rate of that of each mushroom was the highest at the concentration of $ED_{50}$ of benomyl. The mycelial growth of P. ostreatus was increased progressively as the number of successive culturing increased, while that of P. florida and A. bisporus was increased until they were cultured successively up to 5 times and 7 times, respectively, but they were decreased after that. Mutant sectors of mycelia were induced by successive treatment of benomyl. Mutant sectors of P. ostreatus appeared earlier than those of P. florida and all of them were induced earlier on the media of low contration of benomyl than on that of high concentration. The mycelia of mutant sectors induced by benomyl treatment grow faster than those of mother colony treated with benomyl successively, but there was no difference in resistance against the fungicide between them. The increase of mycelial growth of the mushrooms culturing successively on media containing benomyl indicated that they might obtain the resistance against benomyl.

• The Korean Journal of Mycology
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• v.43 no.4
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• pp.260-266
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• 2015

To examine the changes in resistance to benomyl of Fusarium species causing bakanae disease, Fusarium isolates were collected in Korea, and pathogenicity tests were performed using rice seeds in vitro. Minimum inhibitory concentration (MIC) and effective concentration of 50% ($EC_{50}$) values of isolates were examined using the agar dilution method. High frequency distribution of MIC values to benomyl against isolates collected in 2006~2007 and 2013~2014 years were $1.5625{\sim}3.125{\mu}g/mL$ and more than $25{\mu}g/mL$, respectively. The mean $EC_{50}$ value of isolates to benomyl increased from $1.6397{\mu}g/mL$ in 2006~2007 to $2.4892{\mu}g/mL$ in 2013~2014. Based on MIC and $EC_{50}$ values of isolates, the moderate resistance of benomyl were determined as more than $25{\mu}g/mL$ of MIC and less $2.4{\mu}g/mL$ of $EC_{50}$ value, and resistant isolates to benomyl were determined as more than $2.4{\mu}g/mL$ of $EC_{50}$ value. Compared with the ratio of resistant isolates in 2006~2007, the ratio of resistance isolates in 2013~2014 increased from 12.5% to 36.4%. In addition, multiple resistant isolates to prochloraz as well as benomyl increased to 20.3% in 2013~2014.

• The Plant Pathology Journal
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• v.18 no.4
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• pp.216-220
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• 2002

Seed decay of soybean caused by Diaporthe phaseolorum, Colletotrichum truncatum and Cercospora kikuchii is a serious disease when soybean is harvested under warm and wet weather conditions. Benomyl has been used for controlling the disease, however, benomyl application may be limited due to common occurrence of resistance. The efficacy of 21 fungicides against the pathogens was evaluated in vitro. Among the fungicides tested, benomyl, carbendazim, fluazinam, iprodione+propineb, thiophanate-methyl, and triflumizole were found effective and were evaluated for their ability to control the seed pathogens. Fluazinam completely inhibited mycelial growth at a concentration of 100 $\mu\textrm{g}$/$\textrm{m}{\ell}$ for D. phaseolorum; and at a concentration of 500 $\mu\textrm{g}$/$\textrm{m}{\ell}$ for C. truncatum and C. kikuchii. $EC_90$ values of fluazinam were similar to that of benomyl. Because fluazinam, iprodione+propineb, and triflumizole were found effective against the seed pathogens, these were subjected for field-testing. Suppression of pod and seed infection by fluazinam and iprodione+propineb was as high as that of benomyl without any reduction in agronomic characters of soybean. This study shows that fluazinam and iprodione+propineb may be used in combination with benomyl to control seed pathogens, manage resistance, and ensure production of high quality soybean seeds.

• Korean Journal Plant Pathology
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• v.14 no.4
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• pp.367-370
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• 1998

Monilina fructicola, the brown rot fungus of stone fruits, was isolated from overwintering mummies and peduncles on peach trees from February to March, 1998. The resistant population of these isolates to benzimidazole (benomyl, carbendazim and thiophanate-methyl) and dicarboximide (iprodione, vinclozolin and procymidone) was examined. Among 417 isolates, the incidence of isolates resistant to benomyl, carbendazim, and thiophanate-methyl were 45 (10.8%), 47 (11.3%), and 46 (11.0%), respectively. Forty two (10.0%) isolates showed cross-resistance to benzimidazole fungicides. On the other hand, the resistant isolates against iprodione, vinclozolin and procymidone were 186 (44.6%), 1 (0.2%) and 150 (36.0%), respectively. Among the isolates, 116 (27.8%) showed cross-resistance to iprodione and procymidone. Moreover, 27 (6.5%) of 417 isolates showed double-resistance to both benzimidazole (benomyl) and dicarboximide (iprodione).

• The Korean Journal of Pesticide Science
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• v.14 no.4
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• pp.427-432
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• 2010

Rice bakanae disease caused by Fusarium fujikuroi is one of the most serious rice diseases in Korea. From 2006 to 2009, 118 F. fujikuroi isolates were collected from various regions of rice fields in Korea. Resistance assay of 118 F. fujikuroi isolates to prochloraz, tebuconazole, and benomyl, were performed using agar dilution method. To investigate inhibitory effects of the fungicides, minimum inhibitory concentration of mycelial growth (MIC) and effective concentration inhibiting mycelial growth by 50% ($EC_{50}$) for 118 isolates were calculated using Sigmaplot 8.02 (Antro, SPSS UK, Ltd). Based on the means of $EC_{50}$ values, baseline resistance values were determined as $0.5{\mu}g{\cdot}mL^{-1}$ for prochloraz, $5.0{\mu}g{\cdot}mL^{-1}$ for tebuconazole and $2.5{\mu}g{\cdot}mL^{-1}$ for benomyl. Number of resistant isolates to each fungicide was 17, 19 and 43 for prochloraz, tebuconazole and benomyl, respectively. Furthermore, 4 isolates showed the double resistance to both prochloraz and tebuconazole, 6 isolates to prochloraz and benomyl, and 11 isolates to tebuconazole and benomyl. Isolates CF366 and LF335 isolated from Gyeongbuk province were resistant to the three fungicides tested, prochloraz, tebuconazole and benomyl.

• The Plant Pathology Journal
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• v.38 no.6
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• pp.629-636
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• 2022

Colletotrichum species is known as the major causal pathogen of red pepper anthracnose in Korea and various groups of fungicides are registered for the management of the disease. However, the consistent use of fungicides has resulted in the development of resistance in many red pepper-growing areas of Korea. Effective management of the occurrence of fungicide resistance depends on constant monitoring and early detection. Thus, in this study, various methods such as agar dilution method (ADM), gene sequencing, allele-specific polymerase chain reaction (PCR), and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) were applied for the detection of benzimidazole resistance among 24 isolates of Colletotrichum acutatum s. lat. and Colletotrichum gloeosporioides s. lat. The result of the ADM showed that C. gloeosporioides s. lat. was classified into sensitive and resistant isolates to benomyl while C. acutatum s. lat. was insensitive at ≥1 ㎍/ml of benomyl. The sequence analysis of the β-tubulin gene showed the presence of a single nucleotide mutation at the 198th amino acid position of five isolates (16CACY14, 16CAYY19, 15HN5, 15KJ1, and 16CAYY7) of C. gloeosporioides s. lat. Allele-specific PCR and PCR-RFLP were used to detect point mutation at 198th amino acid position and this was done within a day unlike ADM which usually takes more than one week and thus saving time and resources that are essential in the fungicide resistance management in the field. Therefore, the molecular techniques established in this study can warrant early detection of benzimidazole fungicide resistance for the adoption of management strategies that can prevent yield losses among farmers.

• Korean Journal Plant Pathology
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• v.14 no.6
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• pp.682-688
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• 1998

Fungicide resistance of 48 isolates of Botrytis cinerea collected from citrus in Cheju was investigated and genetic diversity was analyzed with random amplified polymorphic DNA(RAPD). High levels of resistance to benzimidazole fungicides benomyl and thiophanate-methyl and N-phenylcarbamate fungicide diethofencarb were observed. Negative cross resistance was clear between benzimidazole and N-phenylcarbamate fungicides, and multiple resistance to the fungicides was also observed. There was cross resistance among the dicarboximide fungicides procymidione, vinclozolin and iprodione as it was observed between the benzimidazole fungicides benomyl and thiophanate-methyl. The lowest levels of resistance were to the dicarboximide fungicides, but no sensitive isolate to polyoxin B was observed. The isolates showed genetically diverse RAPD profiles according to the geographic origin collected, but there was no significant correaltion between RAPD profiles of genomic DNA and the levels of fungicide resistance of the isolates. The isolates showed genetically diverse RAPD profiles, indicating that genetic differentiation had already occurred in the populations of B. cinerea distributed in Cheju.

• The Korean Journal of Mycology
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• v.22 no.3
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• pp.260-265
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• 1994

Since around 1980 apple rot caused by Botryosphaeria dothidea has become prevalent throughout the growing areas in Korea, during which period chemical controls have been executed with no notable improvement. Results of investigations on resistance of the causal fungus to its control chemical are as followings; The susceptible fungal isolates showed no mycelial growth at $150\;{\mu}g/ml$ of benomyl whereas the resistant isolates showed 7-13 mm growth at $300\;{\mu}g/ml$ and 6-8 mm at $2,400\;{\mu}g/ml$ of this fungicide. At the latter high concentration, spore germination of the resistant isolates was 5-9% while that of the susceptible isolates was 0%. Within the range of $20-2,400\;{\mu}g/ml$ tested, the susceptible isolates were unable to form pycnidia, but the resistant isolates formed abundant pycnidia at the lower concentration with decreasing pycnidia along with the higher concentration.

• The Plant Pathology Journal
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• v.23 no.3
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• pp.187-192
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• 2007

The anthracnose disease on pepper fruits in Korea was caused by Colletotrichum acutatum as well as C. gloeosporioides. Since C. acutatum showed less sensitivity to benomyl, it was analyzed whether the less sensitivity was given by the same mechanism for the fungicide resistance of C. gloeosporioides. The isolates of C. acutatum were less sensitive to the three benzimidazole fungicides tested, benomyl, carbendazim, and thiophanate-methyl. However, the of C. acutatum isolates were different from the resistant isolates of C. gloeosporioides in their response to diethofencarb, one of N-phenyl-carbamates; the former was still less sensitive to diethofencarb than the latter. The differences in the resistance mechanisms in two species were conspicuous in sequence analysis of the tub2 genes. The genes from C. acutatum did not show any non-synonymous base substitutions at the regions known to be correlated with the benzimidazole-resistance. All of these data may indicate that the less sensitivity of C. acutatum to benomyl is based on different mechanism(s) from that of C. gloeosporioides.