• The Korean Journal of Pesticide Science
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• v.19 no.4
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• pp.428-439
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• 2015

Pepper anthracnose caused by Collectotrichum acutaum has been known as one of the most damaging diseases of pepper, which has reduced not only yield but also quality of pepper produce almost every year. This study was conducted to develop control strategy against pepper anthracnose by alternate application of agricultural organic materials and chemical fungicides. The alternate application effect of agricultural organic materials and chemical fungicides for controlling pepper anthracnose were examined in vitro and in the field. First, thirteen microbial agents and twenty two agricultural organic materials were screened for antifungal activity against C. acutatum through the dual culture method and bioassay. As a result, one microbial agent (Bacillus subtilis QST-713) and three agricultural organic materials (sulfur, bordeaux mixture, marine algae extracts) were found to show high inhibition effect against C. acutatum. In the field test, when Iminoctadine tris+thiram, a chemical fungicide for controlling pepper anthracnose, was sprayed, it reduced disease incidence by 89.5%. Meanwhile Sulfur, bordeaux mixture, copper, marine algae extracts and Bacillus subtilis QST-713 showed low disease incidence at the range of 33.1~81.0%. However, when Iminoctadine tris+thiram and agricultural organic materials(bordeaux mixture, marine algae extracts) were applied to pepper fruits alternately two times at 7 days interval, there was a 81.7 and 87.1% reduction in disease, respectively. Consequently, the alternate spray of chemical fungicide (Iminoctadine tris+thiram) and agricultural organic materials (bordeaux mixture, marine algae extracts) could be recommended as a control method to reduce the using amount of chemical fungicide.

• The Korean Journal of Pesticide Science
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• v.18 no.2
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• pp.115-121
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• 2014

This study was performed to investigate the effect of conidial density, wetness period and temperature on conidial germination, appressoria formation and disease incidence. While there was not significantly correlated between conidial density and temperature, and conidial germination and appressoria formation, there was a significant correlation between those factors and disease incidence. The longer wetness period was, the higher the ratio of conidial germination, appressoria formation and the disease incidence was. The optimum conidial density, temperature and wetness period was $1{\times}10^6$ conidia $mL^{-1}$, $30^{\circ}C$ and 5 days, respectively. In case the wetness period was more than 5 days, the typical symptom was not found on pepper fruits because of the overgrowth of mycelia. Using this fruit assay method, which the pepper anthracnose pathogens were inoculated by spraying spore suspension on non-wounded or wounded pepper fruits, control effect of three fungicides were evaluated against pepper anthracnose by the protective and/or the curative application. Propineb showed high protective control activity, while it showed curative control activity on unwounded fruits, but did not showed curative control activity on wounded fruits. Tebuconazole, one of curative fungicide, showed higher control activity in non-wound inoculation than wound inoculation. Trifloxystrobin, one of strobilurin group, showed high both protective and control activity against anthracnose. In conclusion, we supposed that the newly developed in vitro pepper fruit assay can be used to evaluate antifungal activity of control agents against pepper anthracnose.

• Pediatric Infection and Vaccine
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• v.13 no.2
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• pp.155-162
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• 2006

Purpose : Appropriate use of antimicrobials is an essential factor to treat infectious diseases and prevent acquisition of antimicrobial resistant pathogens. This study was undertaken to search that application of computerized management program for restriction of antimicrobials use in a hospital is helpful to decrease antimicrobial use density. Methods : Antibiotics utilization committee decided to restrict the use of 16 antimicrobials(14 expensive drugs having fear of drug resistance by pathogens and additional two drugs with inappropriate using tendency). Retrospective evaluation of antimicrobial user numbers between May and July of 2004 and 2005(study group) was conducted to compare with previous use density during same period of 2002 and 2003(control group). Results : Inpatients number of control group($823.5{\pm}37.1$ persons) was more than study group($809.2{\pm}39.3$ persons, P<0.001), but, outpatients number and hospitalized duration were equal in two groups. Antimicrobial user number/100 inpatients per day of glycopeptides and antifungal agents was equal in two groups, and study group was significantly higher density than control group in the use of carbapenems, piperacillin-tazobactam and quinolones(P<0.001). But study group was significantly lower density than control group in the use of drugs with inappropriately using tendency and expensive cephalosporins having broad antimicrobial spectrum(P<0.001). Conclusion : Application of computerized management program for restriction of antimicrobials use in a hospital is effective to decrease the use density of antimicrobials with inappropriately using tendency, but it is an insufficient measures for the restricted use of other antimicrobials on the whole.

• Research in Plant Disease
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• v.23 no.2
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• pp.159-167
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• 2017

This study was conducted to evaluate the control efficacy of the organic farming materials on cucumber scab caused by Cladosporium cucumerinum PT1 (KACC 48094). The antifungal activities in vitro as well as the suppressive effect of 43 organic farming materials on the spore germination and germ tube growth by inoculating spore suspension on cucumber seedlings in vivo were investigated. Thirteen organic farming materials inhibited the mycelial growth of C. cucumerinum and nine of these were microbial agents. In the screening using cucumber seedlings, six organic farming materials were very effective with control efficacy value of 90%. Among them, Bacillus amyloliquefaciens M27 provided suppressive effect on both mycelial growth and spore germination against cucumber scab. Finally, nine organic farming materials were selected to test the protective and curative effects, and all chosen organic farming materials significantly suppressed disease incidence when applied in the preventive action, in comparison with the curative action. Especially, Bordeaux mixture I and III gave excellent protective control efficacy with control values of 96.7% and 73.3%, respectively, whereas its curative control effect was significant low. Among these, only Thymus quinquecostatus+Sophora extract showed curative activity, although the control value was as low as 50%. This study suggests that cucumber scab can be controlled by some organic farming materials in the farmhouses under comparatively cold and wet condition and protective treatment is more important and efficient.

• The Korean Journal of Pesticide Science
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• v.19 no.1
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• pp.64-70
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• 2015

In order to control garlic white rot (Sclerotium cepivorum), which threatens garlic production in farmers fields, soil solarization (solar sterilization), sclerotia germination inducers and effective microorganisms as biological control agents, and chemical fungicides have been used. Among them, fungicide has been largely used to reduce garlic white rot. In this study, the antifungal activities of five fungicides, prochloraz(a.i. 25%, EC), tebuconazole (a.i. 25%, WP), flutolanil (a.i. 15%, EC), iminoctadine tris-albesilate (a.i. 40%, WP) and isoprothiolane (a.i. 40%, EC) with different mode of action, in mycelial growth, sclerotia germination and sclerotia production, were tested. The inhibitory effects of the 5 fungicides on the mycelial growth, and sclerotia germination and production of garlic white rot pathogen (S. cepivorum T11-2) were investigated on potato dextrose agar (PDA) and their control efficacies were evaluated on garlic flakes. There was no mycelial growth of S. cepivorum T11-2 on PDA amended with $0.8{\mu}g\;mL^{-1}$ of prochloraz or $100{\mu}g\;mL^{-1}$ of tebuconazole. Also prochloraz and tebuconazole inhibited perfectively the sclerotia germination of the pathogen at 10 and $1.0{\mu}g\;mL^{-1}$, respectively. In spite of a very low activity of isoprothiolane in mycelial growth and sclerotia germination of S. cepivorum T11-2, it showed a good inhibitory activity against sclerotia production of S. cepivorum T11-2 on PDA amended with $1.67{\mu}g\;mL^{-1}$. Prochloraz, tebuconazole and flutolanil showed above 70% of control value when they were treated at $100{\mu}g\;mL^{-1}$ using the garlic flake cutting-method.

• Parasites, Hosts and Diseases
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• v.28 no.4
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• pp.241-252
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• 1990

In a basic attempt to develop the prophylactic and therapeutic measures on intestinal giantcystic disease of the Israel carp, C), prinks carpio nudum, the effects of physical and chemical factors on viability or survival of the spores of Thelchcnellus kiteuei were checked in vitro by means of extrusion test on the polar filament. When the fresh spores suspended with 0.45% and 0.9% scdium chloride solution and distilled water were laid at $5^{\circ}C$ and $28^{\circ}C$ for short terms, the extrusion rates increased until the 3rd day, meanwhile when son;e of them were suspended with Tyrode's solution at $-70^{\circ}C$ the rates increased gradually until the 8th day. Viabilities of the spores suspended with 0.9% saline and added antibiotics to the suspension at $5^{\circ}C$ for long terms lasted for 997 days and 1, 256 days (presumed values) at maximum, respectively. The spores suspended with distilled water at $28^{\circ}C$ for long terms survived 152.4 days, but the spores suspended with Tyrode's solution at $-70^{\circ}C$ for long terms showed almost the same viable pattern as early freezing stages up to 780 days. The spores suspended with Tyrode's solution, frozen at $-70^{\circ}C$ and thawed at $5^{\circ}C$, showed the highest rate of extrusion of the polar filament. In the case of frozen spores, the extrusion rates during heating tend to become higher in accordance with the increase of frozen period, and the critical points of 180 day-frozen spores to be killed were generally 78.5 hr. at $60^{\circ}C$, 23.4 hr. at $70^{\circ}C$, 189.1 min. at $80^{\circ}C$ or 10.5 min. at $90^{\circ}C$. The longer the spores were frozen, the more time was needed for the death of spores after thawing; 20 days-17.4 days, 100 days-33.2 days, and 400 days-37.8 days. The longer the spores were frozen, the more time was needed for the death of spores at a conventional when they were dried air drying condition, 540 days-23.5 days, 160 days-21.0 days, and 20 days-14.4 days. On the other hand, the longer the spores were frozen, the more spores were dead rapidly when they were irradiated with 10W UV-ray; 100 days-26.0 hr, 300 days-21.9 hr, and 540 days-13.9 hr. The time needed for killing 200 days-frozen spores by various disinfectants at 1, 000 ppd was 5.2 min. by calcium oxide, 10.4 min. by potassium permanganate, 27.8 min. by malachite green and 14.3 hr. by formalin. Transient inhibitory effects of the extrusion of the polar filament were observed by various antiprotozoal and antifungal agents in the descending order of ketoconazole. metronidasole and dapsone. The above results presume that full drying, followed by spraying CaO and maintaining sunny condition for a few days on the concrete bottoms of knish farm may be an effective method for the prevention of intestinal giant.cystic disease.