• The Plant Pathology Journal
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• v.25 no.4
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• pp.322-327
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• 2009

A total of 23 isolates of Botrytis cinerea causing the grey mold were collected from infected ginseng in several fields of Korea. The sensitivity to carbendazim and the mixture of carbendazim plus diethofencarb was determined through a mycelial inhibition test on PDA amended with or without fungicides. B. cinerea isolates were classified as 3 phenotypes, which were the first phenotype resistant to both of carbendazim and the mixture ($Car^RMix^R$), the second one resistant to carbendazim and sensitive to the mixture ($Car^RMix^S$), and the last one sensitive to both of them ($Car^RMix^S$). Carbendazim resistance correlated with a single mutation $\beta$-tubulin gene of B. cinerea amplified with primer pair tubkjhL and tubkjhR causing a change of glutamate to alanine at amino acid position 198. Furthermore, the substitution of valine for glutamate led the resistance to carbendazim and the mixture at the same position of amino acid. PCR-restriction fragment length polymorphism (PCR-RFLP) analysis using the restriction endonuclease, Tsp451 and BstUI allowed differentiation of the PCR fragment of $\beta$-tubulin gene of $Car^SMix^S$ isolates from that of $Car^RMix^R$ and $Car^RMix^S$ isolates. This method will aid in a fast detection of resistance of carbendazim and the mixture of carbendazim plus diethofencarb in B. cinerea in ginseng field.

• Korean Journal Plant Pathology
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• v.14 no.6
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• pp.693-699
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• 1998

Three three hundred and ninety seven isolates of Botrytis cinerea were isolated from infected plants of strawberry, tomato and cucumber from several areas in Korea during 1994∼1996 and the resistance of these isolates against some fungicides were examined. The isolation frequency of phenotypes resistant to carbendazim, procymidone, and diethofencarb were found to be 69.9 43.7, and 31.8%, respectively. The isolates were divided into six phenotypic groups; SSR, SRR, RSS, RRS, RSR and RRR, representing sensitive (S) or resistant (R) to benzimidazole, dicarboximide, and N-phenylcarbamate fungicides in order. The percentage of six phenotypes were 28.2, 2.0, 27.2, 41.0, 0.9 and 0.8%, respectively. On the basis of the mycelial growth inhibition (%) B. cinerea isolates were divided into three classes (class 1; 0∼50%, class 2; 51-99%, class 3; 100% inhibition) on carbendazim and three classes (class 1; 0∼75%, class 2; 76∼99%, class 3; 100% inhibition) on procymidone and the mixture of carbendazim+diethofencarb, respectively. Changes in sensitivity levles to carbendazim and carbendazim+diethofencarb were affected by introduction and increasing ratio of the use of diethofencarb.

• Research in Plant Disease
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• v.13 no.3
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• pp.177-182
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• 2007

In this experiment, 236 isolates of Botrytis cinerea isolated from the lesions of ginseng grey mold in 2005 and 2006 were examined for their sensitivity to fungicide inhibiting ${\beta}-tubulin$ assembly. The baselines of fungicide resistance were determined as 10.0 and $0.2{\mu}g/ml$ of $EC_{50}$ values for carbendazim and the mixture of carbendazim and diethofencarb, respectively. The ratios of isolates resistant to carbendazim in 2005 and 2006 was investigated to be 87.6 and 96.6%, respectively. In the case of the mixture of carbendazim and diethofencarb, the ratio of the resistant isolates was 23.6% for 2005 and 24.5% for 2006. The ratio of the resistant isolates to the mixed fungicide was fluctuated according to regions where isolates of B. cinerea were obtained. In Yeoncheon of Gyeonggi Province, 4.3% of the isolates used in the experiment was resistant in 2005 and no resistant isolate was obtained in 2006. Among 5 regions, the ratio of resistant isolates was the highest as 70.0% in Yecheon of Gyeongbuk Province.

• Research in Plant Disease
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• v.23 no.2
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• pp.150-158
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• 2017

Pear scab caused by Venturia nashicola has been reported as an important disease of pear resulting in lowering the quality of pear fruits. In this study, it was conducted to investigate the relationship between resistance of V. nashicola and mutation of ${\beta}$-tubulin gene and the fungicide resistance in field isolate group in benzimidazole fungicides. Responce of V. nashicola to carbendazim could be classified into 3 groups as sensitive that does not grow at all on PDA amended with $0.16{\mu}g/ml$ of carbendazim, low resistance that could not grow in $4.0{\mu}g/ml$ medium, and high resistance that can grow even at $100{\mu}g/ml$. Thirty isolates of V. nashicola collected from 3 regions as Wonju, Naju, and Okcheon were highly resistant to carbendazim. Analysis of the nucleotide sequence of ${\beta}$-tubulin gene of V. nashicola showed that there was no difference in the nucleotide sequence between the sensitive and the low-resistant isolate, but GAG at codon 198 (glutamic acid) was replaced with GCG (alanine) in the high-resistant isolate. Among 10 isolates obtained from the Okcheon, 5 isolates showed the substitution of glycine for glutamic acid, which were resistant to carbendazim, but more sensitive to the mixture of carbendazim and diethofencarb than others. Through these results, all isolates of V. nashicola isolated in pear orchard were found to be resistant to benzimidazoles. Also, mutants E198A and E198G at ${\beta}$-tubulin were found to be important mechanisms of V. nashicola resistance against benzimidazole fungicides.

• 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).

• Research in Plant Disease
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• v.13 no.3
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• pp.170-176
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• 2007

Effects of fungicides on the mycelial growth of Botrytis cinerea isolated from ginseng leaves were investigated by an agar dilution method. By using a agar dilution method, it was investigated the effect of fungicides, procymidone, carbendazim and the mixture with both of carbendazim and diethofencarb, on the mycelial growth of Botrytis cinerea isolates, which were isolated from infected leaves of ginseng in 2005 and 2006. With MIC (minimum inhibiton concentration) of procymidone against B. cinerea, pathogens were divided into two groups. While one showed the low MIC between 0.8 and $4.0{\mu}g/ml$, the other showed higher MIC above $20{\mu}g/ml$. In terms of the inhibition ratio of mycelial growth at the indicated concentration of procymidone, isolates of B. cinerea were divided into three groups; the sensitive, the intermediate resistant, and the resistant group. Each group was differentiated by $EC_{50}$; the sensitive group showed below $2.0{\mu}g/ml$, the intermediate resistant group between 2.0 to $5.0{\mu}g/ml$, and resistant group above $5.0{\mu}g/ml$. Compared with the ratio of resistant isolates of B. cinerea in 2005, the ratio in 2006 increased from 19.3% to 27.5%. Furthermore, the average $EC_{50}$ value of them increased from $10.0{\mu}g/ml$ in 2005 to $237.3{\mu}g/ml$ in 2006. The ratio of isolates showing the multiple resistance between procymidone and carbendazim was 40.2%, whereas the ratio was 4.0% showing the multiple resistance in the mixture.

• The Plant Pathology Journal
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• v.26 no.1
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• pp.49-56
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• 2010

Thirty-six isolates of Colletotrichum spp. were obtained from infected grapes in two different locations of Korea; 18 isolates from Cheonahn, where carbendazim (MBC) and the mixture of MBC and diethofencarb (NPC) had been applied to control grape ripe rot, and 18 isolates from Cheongju, where no fungicides had been used. Sequences analysis of the internal transcribed spacer (ITS) and the $\beta$-tubulin gene identified 34 of the 36 isolates as Colletotrichum gloeosporioides. The remaining two isolates from Cheongju were identified as C. acutatum. Of the 18 isolates from Cheonahn, 12 were resistant to both MBC and the mixture (MBC+NPC), and six were sensitive to them. All C. gloeosporioides isolates from Cheongju, but not the two C. acutatum isolates, were sensitive to these fungicides. Sequence analysis of the $\beta$-tubulin gene in all isolates revealed that C. gloeosporioides resistant to MBC and MBC+NPC had a tyrosine instead of phenylalanine at the amino acid position 200. The appearance of resistance to MBC and the mixture in C. gloeosporioides correlated with the history of fungicide application in Korea.

• The Plant Pathology Journal
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• v.19 no.1
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• pp.46-50
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• 2003

To evaluate the sensitivity of Monilinia fructicola to dicarboximides used in controlling brown rot of peach, the fungus was isolated from commercial peach orchards in Chochiwon (CH), Chongdo (CD), Gyeongsan (GY), and Youngduk (YO) in Korea. The population shift of dicarboximide-resistant isolates of M. fructicola was investigated for 3 years starting 1998. The frequency of procymidone-resistant isolates (PRI) was higher in CD and GY than in CH and YO. The frequency of PRI was higher in the mid season (July-August) than in the rest of the year. Cross-resistance rate of PRI to iprodione was over 87.8% during the investigation, and double-resistance to both procymidone and carbendazim was less than 10%. However, the rate of cross-resistant isolates to vinclozolin was low. In the orchards in GY and CH without any fungicide spray, the PRI population was persistent and did not vary for 3 years. The results suggest that dicarboximide resistance of M. fructicola could be a problem in controlling brown rot and blossom blight on peach trees because it may take a long time to recover the population with sensitive isolates even in the absence of these fungicides.

• The Korean Journal of Pesticide Science
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• v.19 no.3
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• pp.335-344
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• 2015

It was conducted to identify all 47 isolates obtained from infected fruits of pepper and boxthorn, and to investigate the mycological characteristics and the response to fungicides. All of 11 isolates from pepper were identified as Colletotrichum acutatum included into A2 group. Among 36 isolates from boxthorn, 14 isolates were identified as C. gloeosporioides, and the others were done as C. acutatum, which were composed as A1 group with 15 isolates and A3 with 7 isolates. After incubating the isolates on PDA at $25^{\circ}C$ for 10 days, the colony color of C. acutatum was greyish white, while that of C. gloeosporioides was orange at center of colony and was gradually turned into an greyish white to the periphery. The rate of conidia showing ellongated ellipsoidal shape with round ends was over 95% in C. acutatum isolated from pepper. However, C. acutatum isolated from boxthorn produced ellongated ellipsoidal conidia with the rate of 75%, and the others were pointed at one or both ends. Regardless of species of Colletotrichum, all isolated used in this study was showed an optimal temperature at $25^{\circ}C$. $EC_{50}$ values of all isolates of Colletotrichum spp. to 2 fungicides as carbendazim and the mixture of carbendazim and diethofencarb was investigated by an agar dilution method. With C. acutatum isolates from pepper belonged to A2 group, the mean of $EC_{50}$ value to carbendazim and the mixture of carbendazim and diethofencarb was 0.68 and $3.16{\mu}g/ml$, respectively. In the case of C. acutatum isolates from boxthorn, which were divided into 2 groups as A1 and A3 group, that to carbendazim was 0.21 at A1 and $0.24{\mu}g/ml$ at A3, while that to the mixture was 1.52 and $3.35{\mu}g/ml$. Isolates of C. gloeosporioides showed the mean of $EC_{50}$ value was $0.12{\mu}g/ml$ to carbendazim and $0.92{\mu}g/ml$ to the mixture. The value of resistant factor was higher in the isolates of C. acutatum obtained in boxthorn than those from pepper.

• Research in Plant Disease
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• v.12 no.1
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• pp.32-39
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• 2006

This study has been conducted to investigate the responses of various isolates of four Colletotrichum species such as C. gloeosporioides, C acutatum, C. coccodes, and C. dematium isolated from infected tissues of several crops to fungicides such as carbendazim, carbendazim+diethofencarb, four protective fungicides, and three ergosterol biosynthesis-inhibiting (EBI) fungicides. All the isolates of C. acutatum showed $EC_{50}$ values in a range of 0.001-3.040 ${\mu}g/ml$ against carbandazim, a benzimidazole fungicide. As for the response to carbendazim, the isolates of C. gloeosporioides obtained from pepper, apple, and strawberry were clearly divided into two groups, resistant or sensitive isolates. All the resistant isolates showed $EC_{50}$ values above 1000 ${\mu}g/ml$, whereas the sensitive isolates had lower $EC_{50}$ values than 0.550 ${\mu}g/ml$. The isolates of C. gloeosporioides exhibited a negative cross resistance between carbendazim and diethofencarb (a N-phenylcarbamate fungicide), but isolates of C. acutatum did not. Toward carbendazim, C. coccodes and C. dematium isolates showed a similar response to C. acutatum isolates and the sensitive isolates of C. gioeosporioides, respectively. As for response of Protective fungicides, all the isolates of C. acutatum showed a more resistant reaction than all the isolates of C. gloeosporioides. However, there was no difference among 4 species of Colletotrichum against EBI fungicides.