• Korean Journal of Microbiology
• /
• v.50 no.3
• /
• pp.201-209
• /
• 2014

This study was carried out in order to develop a biological control of anthracnose of red pepper caused by fungal pathogens. In particular, this study focuses on the Colletotrichum species, which includes important fungal pathogens causing a great deal of damage to red pepper. Antagonistic bacteria were isolated from the soil of pepper fields, which were then tested for biocontrol activity against the Colletotrichum gloeosporioides anthracnose pathogen of pepper. Based on the 16S rRNA sequence analysis, the isolated bacterial strain CS-52 was identical to Bacillus sp. The culture broth of Bacillus sp. CS-52 had antifungal activity toward the hyphae and spores of C. gloeosporioides. Moreover, the substances with antifungal activity were optimized when Bacillus sp. CS-52 was grown aerobically in a medium composed of 0.5% glucose, 0.7% $K_2HPO_4$, 0.2% $KH_2PO_4$, 0.3% $NH_4NO_3$, 0.01% $MnSO_4{\cdot}7H_2O$, and 0.15% yeast extract at $30^{\circ}C$. The inhibition of spore formation resulting from cellulase, siderophores, and indole-3-acetic acid (IAA), were produced at 24 h, 48 h, and 72 h, respectively. Bacillus sp. CS-52 also exhibited its potent fungicidal activity against anthracnose in an in vivo test, at a level of 70% when compared to chemical fungicides. These results identified substances with antifungal activity produced by Bacillus sp. CS-52 for the biological control of major plant pathogens in red pepper. Further studies will investigate the synergistic effect promoting better growth and antifungal activity by the formulation of substances with antifungal activity.

• Research in Plant Disease
• /
• v.17 no.1
• /
• pp.86-89
• /
• 2011

Phytophthora blight and anthracnose disease caused by Phytophthora capsici and Collectotrichum gloeosporioides are the most important devastating diseases of red pepper plants, worldwide. Five different bacterial isolates were isolated from the red pepper rhizosphere and non-rhizosphere soil and subsequently tested for antagonistic activity against P. capsisi and C. gloeosporioides. The area of the inhibition zone was taken as a measure for antagonistic activity. Among the 5 isolates tested, S54 exhibited a maximum antagonistic activity under in vitro and in vivo conditions. In greenhouse studies the isolate has successfully reduced the disease symptom. Protect value was 80.8% (Phytophthora blight) and 81.9% (Anthrancnose disease), whereas the infection rate of control plants was 21.3% and 23.2%. Based on the 16S rDNA sequence and API 50CHB Kit analysis the most effective isolate was identified as Bacillus subtilis. The results of the study indicate that the stratin S54 could be used as an potential biological control of Phytophthora blight and anthracnose disease of red pepper.

• Mycobiology
• /
• v.46 no.4
• /
• pp.440-447
• /
• 2018

Dual biocontrol of both insects and plant pathogens has been reported for certain fungal entomopathogens, including Beauveria bassiana and Lecanicillum spp. In this study, we demonstrate, for the first time, the dual biocontrol potential of two fungal isolates identified by morphological and phylogenetic analyses as Isaria javanica. Both these isolates caused mortality in the greater wax moth, and hence can be considered entomopathogens. Spores of the isolates were also pathogenic to nymphs of the green peach aphid (Myzus persicae), with an $LC_{50}$ value of $10^7spores/mL$ 4 days after inoculation and an $LT_{50}$ of 4.2 days with a dose of $10^8spores/mL$. In vitro antifungal assays also demonstrated a strong inhibitory effect on the growth of two fungi that are pathogenic to peppers, Colletotrichum gloeosporioides and Phytophthora capsici. These results indicate that I. javanica isolates could be used as novel biocontrol agents for the simultaneous control of aphids and fungal diseases, such as anthracnose and Phytophthora blight, in an integrated pest management framework for red pepper.

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

• The Korean Journal of Mycology
• /
• v.13 no.4
• /
• pp.227-233
• /
• 1985

Studies on the varietal resistance and effects of nutrients for fungal growth were carried out in order to obtain basic materials for breeding resistant variety and control measures of the red pepper anthracnose disease caused by Colletotrichum dematium f. sp. capsicum. Four cultivars such as Kumchang No. 2, Bulamhouse, Pakistan, Hongilpum were resistant among twenty-one pepper cultivars, and five cultivars including Taiwan pepper were moderate. The remaining twelve cultivars including H-038 and Saegochu were susceptible. These susceptible cultivars were mostly belonged to sweet taste cultivars. Glucose was known the best source for fungal growth, and near 3 percent of carbon concentration was the best for mycelial growth of the fungus. Conidial sporulation was rather decreased by adding high concentrations of C-source, whereas fungal dry weight was a positive tendency in proportion to increasing carbon concentrations. N-sources and vitamins were not remarkable as that for carbon, and rather a decreasing trend for mycelial growth by adding N-source. Especially, the lowest of mycelial growth was in the case of Czapek-Dox plus ammonium sulfate. The medium plus vitamins either niacin or thiamine was slightly increased to mycelial growth.

• Journal of Life Science
• /
• v.16 no.3 s.76
• /
• pp.420-426
• /
• 2006

Bacillus sp. KMU-991 was isolated from Oslo city soils at Norway and shown a strong antifungal activity on red-pepper anthracnose, Colletotrichum gloeosporioides. Bacillus sp. KMU-991 produced a maximum level of antifungal substrate under aerobic incubation at $30^{\circ}C$, 180 rpm for 48 hours in TSB medium(initial pH 7.0) containing 1.0% mannitol and 1.0% ammonium chloride. Precipitate of culture broth by $30{\sim}60%$ ammonium sulfate precipitation exhibited strong antifungal activity against C. gloeosporioides KACC 40804. Butanol extract of cultured broth also shown fungal growth inhibitory activity against Fusarium oxysporum f. sp. radicus-lycopersici KACC 40537, Rhizoctonia solani AG-4 KACC 40142, Botrytis cinerea KACC 40573, Colletotrichum orbiculare KACC 40808, and Phytophthora cambivora KACC 40160 by agar diffusion method.

• Research in Plant Disease
• /
• v.21 no.3
• /
• pp.208-214
• /
• 2015

To develop an effective biopesticide to control pepper anthracnose disease, an isolate which showed strong inhibitory effect on the mycelial growth and conidial germination of Colletotrichum acutatum was selected among the antagonistic bacterial isolates collected from pepper grown soil. The bacterial isolate was identified as Bacillus sp. KBC1004 using 16S rRNA sequence analysis. The liquid culture of KBC1004 was freeze-dried and formulated as a wettable powder(WP). The wettable powder form of KBC1004 required at least 24 hours to activate and to inhibit the conidial germination of C. acutatum. In vitro bioassay using the detached green pepper fruits, biocontrol activity of the WP was not recognizable in simultaneous inoculation, but significant disease suppression was observed pre-treatment (24 hr) of the WP before pathogen inoculation. In field experiment, 4 times foliar applications of the 1/500 diluted wettable powder from the end of June showed great control efficacy similar to that of the chemical fungicide application. These results suggest that the formulated WP product could be an alternative mean to control of pepper anthracnose disease in environmentally friendly farming practices.

• The Korean Journal of Pesticide Science
• /
• v.8 no.3
• /
• pp.231-237
• /
• 2004

Monitoring for the sensitivity of Colletotrichum spp. causing red-pepper anthracnose to chlorothalonil was conducted by the agar dilution method, which were isolated from infected pepper fruits in 1999 and 2002. Among the isolates in 1999 or 2002, their sensitivity to fungicide was fluctuated. Investigating the inhibitory effect of $500{\mu}g/m\ell$ of chlorothalonil on the mycelial growth of Colletotrichum isolates isolated from the infected red-pepper fruits in 1999, the frequency of isolates was 23.4%, which showed 100% of inhibitory effect on mycelial growth, and 29.7% showing below 60%. Isolates in 2002, however, showed 34.6% and 14.8% of inhibitory effect on PDAs including the same concentration of fungicide, respectively, These results showed that the sensitivity of Colletotrichum isolates in 1999 was inferior to that in 2002. According to the sampling region, isolation frequency among isolates in 2002 showing less MIC rather than 1999 was increased in Kyunggi, Kangwon, Kyungbuk and Kyungnam while the frequency of resistant isolates was done in Chungnam, Chungbuk, Cheonnam and Cheonbuk Fungicide monitoring results in this report will be of use on controlling the anthracnose in each region cultivating red-pepper.

• Research in Plant Disease
• /
• v.15 no.2
• /
• pp.88-93
• /
• 2009

In 2008, leaf rot and blight on pepper seeding ("Dokya-chungchung") occurred in a pepper farm at Hwaseong-si, Gyeonggi-do, Korea. The typical symptom is water-soaking and dark brown leaf blight at edges and tips of leaves. The fungal colonies isolated from infected tissues were pinkish at first and turned gradually to gray. Conidia were fusiform, non-septum, and $8.1-17.0{\times}2.0-3.8{\mu}m$ in size. Several specific PCR primers derived from the sequence of the internal transcribed spacer (ITS) region of the rDNA, such as CaINT, CgINT and CcINT were used for the identification of the fungal pathogen. The C. acutatum-specific primer CaINT was amplified single fragment of 496 bp that discriminated C. acutatum from the other species. The pathogenicity test was performed on seedlings and fruits of red pepper. On the basis of the morphological, molecular characteristics and pathogenicity test, we identified as Colletotrichum acutatum. This is the first report on leaf rot and blight on pepper seedling caused by C. acutatum in Korea.

• Research in Plant Disease
• /
• v.20 no.3
• /
• pp.211-215
• /
• 2014

This research was performed to examine the protective activities of the mixtures of pine oil and copper hydroxide against bacterial spot and anthracnose on pepper plants. As for bacterial spot, the treatment of pine oil alone displayed high disease incidence (59.6%) and low protective effect (28.9%). In comparison, the treatments of mixtures and copper hydroxide alone showed protective activities of 66.8-76.1%. The mixture of pine oil and copper hydroxide (4:1) suppressed the most effectively bacterial spot on pepper. On the other hand, the mixture of pine oil and copper hydroxide (4:1) also showed the strongest protective effect against pepper anthracnose among the 4 treatments tested; its disease incidence and disease control value were 49.8% and 41.7%, respectively. The other treatments showed low protective activities with control values of 7.4-17.1%. These results suggested that the mixture of pine oil and copper hydroxide (4:1) can be used for the environmental-friendly disease control of bacterial spot and anthracnose on pepper.