• Korean Journal of Plant Resources
• /
• v.19 no.3
• /
• pp.392-396
• /
• 2006

This study was conducted to evaluate the control effect of fungicides of sclerotinia rot control, growth characteristics, and seed yield in the cultivation of rapeseed. All fungicides treated had no effect on the growth of rapeseed. The major fungicides were mancozeb 75% WP, chlorothalonil 75% WP, dithianon 43% WP. difenoconazole 10% WP, benomyl 50% WP, and propineb 70% WP. Dry seed yield and control were increased largely with chlorothalonil 75% WP ($33g/12{\ell}$), fungicide than the other fungicides Sclerotinia rot. All fungicides had no injury with standard dosage. On the other hand all fungicides had slight injury in the double dosage level for the rapeseed.

• Journal of Applied Biological Chemistry
• /
• v.44 no.1
• /
• pp.27-31
• /
• 2001

Using a new evaluation method, Congo red method, the foliar uptakes of eight fungicides were measured. Among the fungicides tested, fenarimol, myclobutanil, edifenphos, isoprothiolane, and tricyclazole were found to be penetrable (11.0~42.8%), and were continuously absorbed into the leaf regardless of their formulation types. Procymidone, dimethomorpb, and ethaboxan were seldomly absorbed into plant leaf. The uptakes of dimethomorph and ethaboxam were facilitated (18.1~22.7%) in the presence of Koremul-OE-20, as an activator, showing plateau phase at 12h after application. Foliar uptake of fenarimol and myclobutanil into cucumber plant by spray application was larger than that by dropping application, while observed opposite in the cases of dimethomorph and ethaboxam containing activator. Congo red method in conjunction with spraying application used in the present study produced the clear results on foliar uptake of fungicides and therefore proved to be better than the conventional method in which the dropping application of pesticide has been used.

• Microbiology and Biotechnology Letters
• /
• v.25 no.4
• /
• pp.396-402
• /
• 1997

Biocontrol of plant pathogens provides an alternative means of reducing the incidence of plant diseases without the negative aspects of chemical pesticides. Nowdays, as the resistant fungi about the chemical fungicides have revealed and the concern of environment has increased, the biological control of phytopathogenic fungi by the antagonistic microorganisms is very much indispensable. For the selection of strong antagonistic bacterium for biological control agent of rice leafblast and cucumber gray mold rot, the antifungal strain KL-3 strain was selected among 120 strains isolated from the rhizosphere soils. And the strain was identified to be a species of Bacillus subtilis or closely related strain. In several biochemical and in vitro antibiosis tests, antifungal substances of Bacillus sp. KL-3 were presumed heat stable, micromolecular antibiotic substances. In vivo test and vinyl house field test, the antifungal substances of Bacillus sp. KL-3 represented excellent biocontrol ability aganist Alternaria mali, Phyricularia oryzae, and Alternaria kikuchiana as well as broad spectrum of other fungi. In particular, Bacillus sp. KL-3 strain showed more predominant activity than some chemical fungicides against fungi shown to resist chemcal fungicides.

• 한국균학회소식:학술대회논문집
• /
• 2018.05a
• /
• pp.44-44
• /
• 2018

Fusarium head blight (FHB) caused by infection with Fusarium graminearum leads to enormous losses to crop growers, and may contaminate grains with a number of Fusarium mycotoxins that pose serious risks to human and animal health. Antagonistic bacteria that are used to prevent FHB offer attractive alternatives or supplements to synthetic fungicides for controlling FHB without the negative effects of chemical management. Out of 500 bacterial strains isolated from soil, Bacillus amyloliquefaciens JCK-12 showed strong antifungal activity and was considered a potential source for control strategies to reduce FHB. B. amyloliquefaciens JCK-12 produces several cyclic lipopeptides (CLPs) including iturin A, fengycin, and surfactin. Iturin A inhibits spore germination of F. graminearum. Fengycin or surfactin alone did not display any inhibitory activity against spore germination at concentrations less than 30 ug/ml, but a mixture of iturin A, fengycin, and surfactin showed a remarkable synergistic inhibitory effect on F. graminearum spore germination. The fermentation broth and formulation of B. amyloliquefaciens JCK-12 strain reduced the disease incidence of FHB in wheat. Furthermore, co-application of B. amyloliquefaciens JCK-12 and chemical fungicides resulted in synergistic in vitro antifungal effects and significant disease control efficacy against FHB under greenhouse and field conditions, suggesting that B. amyloliquefaciens JCK-12 has a strong chemosensitizing effect. The synergistic antifungal effect of B. amyloliquefaciens JCK-12 and chemical fungicides in combination may result from the cell wall damage and altered cell membrane permeability in the phytopathogenic fungi caused by the CLP mixtures and subsequent increased sensitivity of F. graminearum to fungicides. In addition, B. amyloliquefaciens JCK-12 showed the potential to reduce trichothecenes mycotoxin production. The results of this study indicate that B. amyloliquefaciens JCK-12 could be used as an available biocontrol agent or as a chemosensitizer to chemical fungicides for controlling FHB disease and as a strategy for preventing the contamination of harvested crops with mycotoxins.

• The Plant Pathology Journal
• /
• v.39 no.4
• /
• pp.351-360
• /
• 2023

Citrus melanose, caused by Diaporthe citri, has been one of the serious diseases, and chemical fungicides were used for protection in many citrus orchards of Jeju Island. Establishing a disinfectant resistance management system and reducing pesticide usage would be important for contributing to safe agricultural production. In this study, monitoring of chemical resistance was performed with 40 representative D. citri isolates from many citrus orchards in Jeju Island. Four different fungicides, kresoxim-methyl, benomyl, fluazinam, and prochloraz manganese, with seven different concentrations were tested in vitro by growing the mycelium of the fungal isolates on the artificial medium potato dextrose agar. Among the 40 fungal isolates, 12 isolates were investigated as resistant to kresoxim-methyl which could not inhibit the mycelium growth to more than 50%. Especially isolate NEL21-2 was also resistant against benomyl, whose hyphae grew well even on the highest chemical concentration. However, any chemical resistance of fungal isolates was found against neither fluazinam nor prochloraz manganese. On the other hand, in vivo bio-testing of some resistant isolates was performed against both kresoxim-methyl and benomyl on young citrus leaves. Typical melanose symptoms developed on the citrus leaves pre-treated with both agrochemicals after inoculation with the resistant isolates. However, no or less symptoms were observed when the susceptible isolates were inoculated. Based on these results, it was suggested that some resistant isolates of D. citri occurred against both systemic fungicides, which may be valuable to build a strategy for protecting citrus disease.

• Bulletin of the Korean Chemical Society
• /
• v.18 no.5
• /
• pp.534-540
• /
• 1997

4H,6H-Furo[3,4-c]isoxazoles (Ⅰ-Ⅳ), potential fungicides, have been designed and synthesized via intramolecular [2+3] cycloaddition of nitroalkyne 3 as a key step. The broad spectrum of fungicidal activities of furoisoxazoles (Ⅰ-Ⅳ) were observed on plant pathogens at 250 ppm. Furoisoxazoles Ⅱ, Ⅲ with chlorophenyl at 6-position and methyl or alkylated oxime group at 3-position gave effective control of plant diseases. The furoisoxazole Ⅳ with a chlorophenyl group at 4-position also resulted in high fungicidal activities.

• The Korean Journal of Pesticide Science
• /
• v.6 no.1
• /
• pp.1-8
• /
• 2002

Recent progress of several kinds of compounds which have been synthesized or isolated from natural fungi for screening or conducting test as agricultural fungicides as well as some formulations for wood stain and decay control have been reviewed in this paper in China. Comments were pointed for Chinas further research and development of fungicides as well as pesticides.

• The Plant Pathology Journal
• /
• v.37 no.1
• /
• pp.79-85
• /
• 2021

Chemical and biological agents were evaluated to inhibit Colletotrichum fructicola, Phytophthora cactorum, and Lasiodiplodia theobromae causing strawberry diseases. Mycelial growths of C. fructicola were gradually arrested by increasing concentrations of fungicides pyraclostrobin and iminoctadine tris (albesilate). P. cactorum and L. theobromae were more sensitive to pyraclostrobin compared to C. fructicola, but iminoctadine tris (albesilate) was not or less effective to limit P. cactorum or L. theobromae, respectively. Bacillus siamensis H30-3 was antagonistic against the three pathogens by diffusible as well as volatile molecules, and evidently reduced aerial mycelial formation of P. cactorum. B. siamensis H30-3 growth was declined by at least 0.025 mg/ml of pyraclostrobin. The two fungicides additively inhibited mycelial growths of C. fructicola, but not of P. cactorum and L. theobromae. B. siamensis H30-3 volatiles led to less growth of C. fructicola than one reduced by the fungicides. Taken together, in vitro antimicrobial activities of the two fungicides together with or without B. siamensis H30-3 volatiles may be cautiously incorporated into integrated management of strawberry diseases dependent on causal pathogens.

• The Korean Journal of Pesticide Science
• /
• v.3 no.3
• /
• pp.37-44
• /
• 1999

Two sulphamide (dichlofluanid and tolylfluanid) and three dicarboximide fungicides (iprodione, vinclozolin, procymidone) were used to investigate the correlation between in vitro antifungal activities and in vivo disease controlling activities against Botrytis cinerea, a causal agent of tomato gray mold and to develop efficient in vitro assays. They controlled effectively the development of tomato gray mold disease in vivo and their controlling activities were similar one another. However, several in vitro assays revealed that their in vitro antifungal activities were quite different between sulphamide and dicarboximide fungicides; the formers showed stronger inhibition activities for spore germination than the latters, whereas the formers inhibited mycelial growth less severely than the latters. The results indicate that the fungicides having different modes of action can show different in vitro antifungal activities according to in vitro assays, even if they have similar in vivo disease controlling activities. On the other hand, two rapid and efficient in vitro assays named Microtiter plate methods I (MPM I) and II (MPM II) were developed for the evaluation of fungicides for inhibitory activities against spore germination and mycelial growth of B. cinerea, respectively. The antifungal activities of five fungicides of two chemical groups in MPM I and II were correlated with the inhibitory activities against spore germination and mycelial growth using solid media, respectively.

• Bulletin of the Korean Chemical Society
• /
• v.33 no.5
• /
• pp.1703-1706
• /
• 2012

Rice blast is the most serious disease of rice due to its harmfulness and its world wide distribution. $Magnaporthe$ $grisea$ is the cause of rice blast disease and destroys rice enough to feed several tens of millions of people each year. Fungicides are commonly used to control rice blast. But $M.$ $grisea$ acquires resistance to chemical treatments by genetic mutations. 2-Phenylimino-1,3-thiazolines were proposed as a novel class of fungicides against $M.$ $grisea$ in the previous study. To develop compounds with a higher biological activity, a new series of 2-phenylimino-1,3-thiazolines was synthesized and its fungicidal activity was determined against $M.$ $grisea$. The QSAR analysis was carried out on a series of 2-phenylimino-1,3-thiazolines. The QSAR results showed the dependence of fungicidal activity on the structural and physicochemical features of 2-phenylimino-1,3-thiazolines. Our results could be used as guidelines for the study of the mode of action and further design of optimal fungicides.