• The Korean Journal of Pesticide Science
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• v.11 no.4
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• pp.305-312
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• 2007

It was the investigated the response to metalaxyl of Phytophthora capsici isolates collected in 2005 and 2006. With effective concentrations ($EC_{50}$) of metalaxyl causing 50% growth inhibition, resistance baseline was determined as more than $1.0\;{\mu}g\;mL^{-1}$. Based on the resistance baseline, isolation frequency (%) of P. capsici resistant to metalaxyl was 29.0% and 218% in 2005 and 2006, respectively. Among the isolates of P. capsici obtained in 2006, the isolation was variable; 33.3% in Chungnam, 26.3% in Chungbuk and 11.1% in Gyeongbuk. Two isolates of metalaxyl-sensitive (MS) and too isolates of metalaxyl-resistant (MR) P. capsici were selected and then used to investigate the activity of metalaxyl to their development stages. Even though there was a difference in mycelial growth inhibition by metalaxyl between MS and MR isolates, the fungicide was not active or nearly to sporangium germination, zoospore release, and zoospore germination of both MS and MR isolates. However, the fungicide showed weak activity against sporangium germination and zoospore release of P. capsici, not related with its resistance. Also, it was not inhibitory to zoospore germination of both resistant and sensitive isolates. In a greenhouse test, it showed 100% of control value against P. capsici 06-86 sensitive to metalaxyl, when it was applied by soil-drenching at $25\;{\mu}g\;mL^{-1}$. However, 06-130 and 16-155 resistant to metalaxyl showed less than 20% of control value.

• Korean Journal of Plant Resources
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• v.21 no.4
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• pp.260-264
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• 2008

For the resistance test for Phytophthora blight of $T_1$ and $T_2$ transformants in pepper, Phytophthora blight fungus was inoculated to seedlings of the $T_1$ and $T_2$ transformants by concentration (density: zoospore $10^3/ml$). Occurrence rate of blight at 5days after inoculation was 4.0 % in T1-1 line and 10.0% in $T_1-2$ line, and its rate for 12 days after inoculation was 52.0% in $T_1-1$ line, 64.0% in $T_1-2$ line, respectively. Therefore, the lower occurrence rate to blight was enable to select resistant transformants in the some inoculation density (zoospore $10^3/ml$), meanwhile 'Kumtap' and 'Subicho' were 100% in highest occurrence rate to blight. For field test, in which blight was commonly occurred, of the Youngyang Pepper Experiment Station, the acquired transformant resisting to blight was similar to characteristics of domestic varieties, 'Subic ho' for fruit shape, but there are some differences in growth, days to flowering, fruit characteristics. Occurrence of blight in $T_2-1-6$, and $T_2-4-9$ lines was smaller approxmately 30% than commercial varieties, 'Kumtap', although occurrence of blight in field was showed higher difference among tested lines. In this study, we concluded that the transformants showing blight resistance selected from habitual field could be fixed at every generation, and the developed transformation system was also considered to develop transformants in pepper.

• Korean Journal of Environmental Biology
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• v.21 no.3
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• pp.292-296
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• 2003

Effects of aybusculayr mycorrhizal fungus (aMF), Glomus manihot, on plant growth and nutrient uptake on pepper (Capsicum annuum L.) seedlings were evaluated in the nursery experiment. Five different strains of pepper, Chungok, Shingang, Manitta, Gonggongchil, and Shintaeyang, were used in this study. Total fresh weight, nutrient (nitrogen, phosphate and potassium) uptake were increased in all strains inoculated with G. manihot alone and G. manihot and rock phosphate over control at 2 weeks after seeding. Plant weight and phosphate uptake in plants treated with AMF were significantly higher (P< 0.05) than those of control at 6 weeks after seeding. The treatment with G. manihot and rock phosphate gave better plant performance than the treatment with G. manihot alone at 6 weeks after seeding. The lengths of pathogenic symptom on pepper by Phytophthora capsici were reduced significantly by the inoculation of G. manihot spores, Therefore, it would be expected that AMF can be used as the biocontrol agent on pathogens in pepper.

• Proceedings of the KAIS Fall Conference
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• 2011.05b
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• pp.937-940
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• 2011

물/유기용매의 혼합용액에 키토산을 분산시키고 이 현탁액에 글리시딜 트리알킬 암모늄염, 글리시딜 아릴염 등의 에테르 시약을 상온에서 현탁상태로 반응시켜 4급화 키토산을 제조하는 새로은 방법을 개발하였다. 이 방법으로 합성한 결과 수득율이 90%이상이었으며 후처리과정이 필요없었다. 4급화 키토산의 균에 대한 최소저지농도(MIC)를 조사한 결과 E. coli O157:H7 균주의 MIC는 0.007%-0.01%(70-100ppm)로 추정되었고 V. vulnificus 균주의 MIC는 0.005%(50ppm)정도이고 V.vulnificus 균주의 MIC는 0.007%(70ppm)이었다. 작물에 대한 항균성을 알아보기 위하여 4N-키토산의 항균 활성만이 검정되었는데, 4N-키토산은 고추 역병균인 P. capsici에 대하여 가장 높은 항균 활성을 보여 4,000 ppm에서부터 키토산 무첨가 대조구에 비하여 항균활성을 보였으며 P. capsici보다는 약하지만 잿빛곰팡이병균 B. cinerea에 대하여도 약간의 항균 활성을 보이고 있어, 16,000 ppm에서는 항균서이 뚜렷이 나타났으나 고추 탄저병균인 C. gloeosporioides에 대해서는 16,000 ppm 이라는 높은 농도에서도 항균 활성을 전혀 보이고 있지 않았다.

• The Korean Journal of Pesticide Science
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• v.11 no.3
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• pp.186-193
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• 2007

Characteristics and control activity of copper hydroxide against pepper phytophthora blight caused by Phytophthora capsici were investigated in a greenhouse and a pepper field Copper hydroxide strongly inhibited the germination of zoosporangia and zoospores of P. capsici JHCS 2-5, showing $EC_{50}$ value by 0.6 and 0.3 ${\mu}g\;mL^{-1}$. With 1,040 ${\mu}g\;mL^{-1}$ of copper hydroxide in a greenhouse it showed 80% of the control value by soil-drenching application, while 16% by leaf-spraying. However, when it was treated enough to runoff to soil by leaf-spraying application with 50 ml per a pepper plant, it controlled a pepper phytophthora blight by 94.6 % of control value. Copper hydroxide showed a high protective activity at 1 and 3 days before application, while no curative activity. In a field it showed a high activity of 91%, when pepper plants were treated with copper hydorxide 4 times with a intervals of 10 days.

• The Korean Journal of Mycology
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• v.18 no.4
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• pp.203-208
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• 1990

Sexual reproductive structure of Phytophthora capsici in vitro was round shape with thick wall and $24.4\;{\mu}m$ of diameter ranging $20-32.5\;{\mu}m$. Oogonium was $26.7\;{\mu}m$ $(21-37.5\;{\mu}m$) and $6.5-{\times}5.4m$ $(6-8{\times}5-6{\mu}m)$ for antheridium as doughnut shaped. Since mycelial contact of the paired cultures initiated right after inoculation, mycelial expansion phase was followed. Oospore morphogensis could be divided into the four phases for reproducing adult oospores. The optimum temperature for oospore reproduction was $20-24^{\circ}C$, whereas a retard trend for oospore formation was at the temperature above $25^{\circ}C$. Korean squash agar medium showed a higher oospore formation than the existing V-8 agar medium. Red pepper fruit agar medium was next. No oospore was reproduced on the red pepper leaf medium. Diurnal light with $1800{\pm}300$ and $800{\pm}300$ Lux showed rather retardation for oospore formation than dark conditions.

• Current Research on Agriculture and Life Sciences
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• v.9
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• pp.127-133
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• 1991

PI201232, a pepper line resistant to Phytophthora capsici Leonian, was crossed with PI2713222 and P1163192, resistant to Xanthomonas campestTis pv. vesicatoria (Doidge) Dye and inheritance of the resistance to each disease and genetic relationship between the two disease resistances was studied. Non-hypersensitive resistance to race 3 of X. c. pv. vesicatoria of PI271322 was inherited in a quantitative mode. Resitance to P. capsici of PI201232 was inherited in a mode close to two dominant alleles. Hypersensitive resistance to race 1 of X. c. pv. vesicatoria of PI271322 was inherited in a mode of single dominant allele. PI 163192 was consistently resistant to both race 1 and race 3 of X c. pv. vesicatoria and the resistance was inherited in a quantitative mode with high dominance effect. Resistance to X. c. pv. vesicatoria was inherited independently from resistance to P. capsici.

• Current Research on Agriculture and Life Sciences
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• v.17
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• pp.7-13
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• 1999

Thirty bacteria were isolated from the red pepper rhizosphere. The isolates were screened for antagonism to Alternaria alteranta causing red pepper black rot. Antagonistic bacterium No. J-24 was selected among the isolated bacteria and was identified as Bacillus subtilis based on morphological and physiological characteristics and MIDI system. B. subtilis J-24 showed antifungal activities against A. alternata(inhibition percentage, 99%), Botrytis cinerea, Phytophthora capsici, Pythium ultimum, Colletotrichum gloeosporioides, Stemphylium botryosum. The growth of red pepper seedling was promoted as compared to control when the microbial inoculants was mixed in bed soil. In the mixed microbial inoculants bed soil, the leaf area of red pepper was increased of 15 percent, the hypocotyl weight 12 percent, the root length 12 percent, total dry weight 13 percent as compared to those grown in the general bed soil.

• Research in Plant Disease
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• v.18 no.4
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• pp.317-323
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• 2012

The study aims to identify the pathogenicity of Phytophthora. capsici isolates in major pepper-producing areas in Korea and the inherit genetic pattern of phytophthora blight resistance by inocula. With five kinds of testing materials including 'Kataguma (Sakata Korea)' peppers, a disease-susceptible material, '#308', a phytophthora blight resistance material, 'CM334', and their $F_1$ and $F_2$, respective isolates of P. capsici obtained from Icheon, Eumseong, Buan, Imsil and Yeongyang regions together with six kinds of peppers' inoculum including PA-159 (KACC No.40482) received from Korean Agricultural Culture Collection were used for inoculation. The disease-susceptible material '#308', the resistant material 'CM334' and the non-segregating generation of $F_1$ represented 4.94-5.00, 1.00-1.07, and 1.01-1.08 phytophthora blight incidence respectively in the group comparison by isolate. This result means that the phytophthora blight resistance was clearly distinguished among testing materials in the group comparison by P. capsici isolate. Moreover, $F_2$ segregating generation showed 1.79-2.31 phytophthora blight incidence which turned out to be identical in the group comparison by the six isolates of P. capsici isolate and with similarity between both the resistant and susceptible materials. Thus, the result proved that using the six isolates of P. capsici tested as inocula was suitable to investigate the phytophthora blight resistance. When it comes to group comparison of $F_2$ segregation generation, however, isolates were divided with PA-159 isolate being the center: a group consisting of isolates from Icheon, Buan, and Imsil and a group consisting of Yeongyang and Eumseong isolates with higher pathogenicity. The expected segregation ratio of the phytophthora blight resistance in $F_2$ generation by isolate was analyzed. PA-159 isolate showed 3:1 or 9:3:3:1, indicating that one to two genes were involved. On the other hand, results also proved that there is an interaction of genes since both Eumseong and Yeongyang isolates showed a segregation ratio of 11:5 while the Icheon isolate represented 12:3:1.

• Research in Plant Disease
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• v.13 no.2
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• pp.93-97
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• 2007

The microorganisms with the antifungal activity against Phytophthora capsici and Colletotrichum acutatum and the plant growth promotion activity were screened from forest soils of Moon-gyeong (Juheul Mountain), Gyeongsangbuk-do. One of the isolates, strain MG 121 showed antifungal activity against P. capsici and C. acutatum and possessed phosphate solubilization activity was selected to development biocontrol agent. The strain MG 121 was identified as Streptomyces sp. by analysis of 16S rDNA. On the test with pepper fruits, the strain inhibited disease incidences of late blight and anthracnose over 80%. In greenhouse test, plant height, the number of leaf, fresh weight and roots length of pepper plants upon treatment of culture suspension of Streptomyces sp. MG 121 were significantly higher than those without the bacterial cells. In addition, strain MG 121 was capable to solublize rock-phosphate after incubation for 144 hours in potato dextrose broth. The concentration of soluble phosphate in PDB amended with 0.5% rock-phosphate was increased up to $765{\mu}g/ml$.