• Research in Plant Disease
• /
• v.17 no.1
• /
• pp.25-31
• /
• 2011

Rust causes significant losses in the yield and quality of various crops. The development of new effective and environmentally benign agents against the pathogen is of great interest. In the course of searching a natural antifungal compound from medicinal plants, we found that the methanol extract of Angelica gigas roots had a potent control efficacy against wheat leaf rust (WLR) caused by Puccinia recondita. The antifungal substance was isolated from the methanol extract by silica gel column chromatography, alumina column chromatography and $C_{18}$ preparative HPLC. It was identified as decursinol angelate by EI-MS and $^1H$-NMR data. In in vivo test, decursinol angelate effectively suppressed the development of WLR and red pepper anthracnose (RPA) among the 6 plant diseases tested. In addition, the wettable powder-type formulation of ethyl acetate extract of A. gigas roots significantly suppressed the development of WLR. The crude extract containing decursinol angelate and the chemical appear to be a potential candidate for control of WLR. In addition, this is the first report on the in vivo antifungal activity of decursinol angelate against WLR as well as RPA.

• The Korean Journal of Pesticide Science
• /
• v.7 no.4
• /
• pp.302-309
• /
• 2003

Disease control activities of 230 triazolyl quinoline derivatives were investigated against six plant diseases such as rice blast, rice sheath blight, tomato gray mold, tomato late blight, wheat leaf rust (WLR) and barley powdery mildew (BPM). New triazolyl quinolines, KSI-4315 and KSI-4317 exhibited a great in vivo control activities against WLR and BPM, and then were selected for further tests such as preventive, curative, systemic, and persistence against WLR and BPM. The KSI-4315 and KSI-4317 contained MeS moiety and MsO moiety in carbon 4-position, respectively. They possessed both preventive activity and curative activity against WLR and BPM. KSI-4317 showed the better control activity than KSI-4315 against BPM, while KSI-4315 represented the better antifungal activity against WLR. Good persistence of KSI-4315 and KSI-4317 were also observed against WLR and BPM. Persistence of KSI-4315 was similar to that of KSI-4317 on WLR, but KSI-4317 was superior to KSI-4315 on BPM in its persistence. Systemic disease control of KSI-4315 and KSI-4317 was investigated by examining translaminar activity from leaf-under-surface to leaf-upper-surface, systemic activities by leaf to leaf movement and the effect of drenching treatment. Systemicities of KSI-4315 and KSI-4317 were not observed in wheat, but KSI-4317 showed more predominant systemicity than KSI-4315 in barley. These results suggest that KSI-4317 would potentially control WLR and BPM in the fields.

• Applied Biological Chemistry
• /
• v.46 no.2
• /
• pp.150-153
• /
• 2003

Methanol extract obtained from Lindera erythocarpa leaves was successively fractionated with n-hexane, ethylacetate, n-butanol, and $H_2O$. From ethylacetate fraction, an active fraction was isolated through repeated silica gel column chromatography and recrystallization, and was identified as a stereoisomer complex of methyllucidone by MS and MMR analyses. The complex showed 85% antifungal activity at 50 {\mu}g/ml$ against the disease wheat leaf rust.

• The Korean Journal of Pesticide Science
• /
• v.9 no.2
• /
• pp.122-131
• /
• 2005

For development of new agrochemical fungicide, syntheses of pyrrolo[2,1-b]thiazole carboxanilide derivatives 9 and antifungal screening against 6 kinds of plant pathogens were carried out. Functionalization of carboxylic acid on C-2 into carboxanilide in the pyrrolo[2,1-b]thiazole resulted in new 20 candidates, in which are ${\alpha},{\beta}$-unsaturated carboxanilide and methyl groups that are in cis relationship. Treatment of acetoxy-1,4-thiazin with magnesium in refluxing methanol gave pyrrolo[2,1-b]thiazole ethyl ester 4 in higher yield than that of the previous report. Hydrolysis of this compound afforded the corresponding acid 5, which reacted with aniline derivatives in the presence of coupling reagent, DIC to give pyrrolo[2,1-b]thiazole carboxanilides 9. As the result of in vivo antifungal assay of 9 against rice blast, rice sheath blight, cucumber gray mold, tomato late blight, wheat leaf rust, and barley powdery mildew, some compounds showed selectively antifungal activities against the rice blast and wheat leaf rust.

• Applied Biological Chemistry
• /
• v.44 no.3
• /
• pp.191-196
• /
• 2001

${\alpha},{\beta}$-Unsaturated carboxanilides 5 with trifluromethylated dihydro-1,4-oxathiins were synthesized for the development of new agrochemical fungicide. Chlorination of trifluoromethylated ${\beta}-keto$ ester 6 followed by the reaction with 1,2-mercaptoethanol gave intermediate 1,4-oxathiane 11. Without purification of 11, substitution of hydroxy group by chlorine, followed by dehydrochlorination of 10 in the presence of triethylamine afforded trifluoromethylated dihydro-1,4-oxathiin ethyl ester 9. Acylation of the hydroxy group of the carboxylic acid 12 followed by treatment of various amines gave the corresponding trifluoromethylated dihydro-1,4-oxathiin carboxamides 5. Antifungal screening (in vivo) of the synthesized compounds against typical plant diseases, which include rice blast, rice sheath blight, cucumber gray mold, tomato late blight, wheat leaf rust, and barley powdery mildew, was carried out. Where meta position of the phenyl group was substituted with isopropoxy or isopropyl group, excellent antifungal activities against rice sheath blight and wheat leaf rust were detected.

• The Korean Journal of Pesticide Science
• /
• v.8 no.4
• /
• pp.338-346
• /
• 2004

The methanol extract of Chloranthus japonicus roots effectively controlled the development of rice blast(Magnaporthe grisea), rice sheath blight(Corticium sasaki), tomato pay mold(Btrytis cinerea), tomato late blight(Phytophthora infestans), and wheat leaf rust(Puccinia recondita). From the methanol extract of C. japonicus roots, three antifungal substances were isolated. Their chemical structures were determined to be shizukanols B, C, and D mainly by mass and NMR spectral data. Among the three substances, shizukanol C showed the strongest inhibitory activity against mycelial growth of the plant pathogenic fungi tested; it completely inhibited mycelial growth of M. grisea. Colletotrichum gloeosporioides, and C. acutatum at concentrations of more than $12.5{\mu}g$/ and P. infestans at concentrations of more than $3.13{\mu}g/m\ell$. They also controlled effectively the development of rice blast and wheat leaf rust. On the other hand, they caused phytotoxic symptoms on barley leaves and inhibited the growth of duckweed (Lemna paucicostata) with $EC_{50}$ values of $30.0{\mu}g/m\ell$ for shizukanol B, $49.9{\mu}g/m\ell$ for shizukanol C, and $154{\mu}g/m\ell$ for shizukanol D. In addition, shizukanol C showed an insecticidal activity against brown planthopper (Nilaparavata lugens), peen peach aphid (Myzus persicae), diamond-back moth (Plutella xylostella), and tobacco cutworm (Spodoptera litura) of the 5 arthropod pests tested with mortality values of more than 60% at a concentration of $1,000{\mu}g/m\ell$.

• The Korean Journal of Pesticide Science
• /
• v.8 no.1
• /
• pp.8-15
• /
• 2004

A synthesis of new $\beta$-ketoacetoanilide chloride derivatives and anti fungal activity of these compounds library against 6 typical plant pathogens were described. Reaction of ketene dimer with chlorine followed by treatment of aniline derivatives gave 89 kinds of the corresponding $\beta$-ketoacetoanilide chlorides through combinatorial synthetic technology using Carousel Reaction Stations. Evaluation of antifungal activity (in vivo) of this chemical library against rice blast, rice sheath blight, tomato aray mold, tomato late blight, wheat leaf rust and barley powdery mildew was carried out. In general, $\beta$-ketoacetoanilide chlorides which present a substituent at 4 in phenyl group(para) of the compounds showed selective control activity against tomato late blight caused by Phytophthora infestans.

• Applied Biological Chemistry
• /
• v.45 no.3
• /
• pp.157-161
• /
• 2002

New 2-benzoylimino-1,3-oxathile derivatives 3 were synthesized and tested their fungicidal activities for the development of new agrochemical fungicide. Reaction of ${\gamma}-chloro-{\beta}-keto$ anilide derivative 5 with potassium thiocyanate followed by the treatment of acid catalyst gave cyclyzed 2-imino-1,3-oxathiole 3. New compound 3 reacted with benzoyl· chlorides to afford the corresponding 2-benzoylimino-1,3-oxathiole derivatives 7. Antifungal screening (in vivo) of the synthesized compounds against typical plant diseases, which include rice blast, rice sheath blight, cucumber gray mold, tomato late blight, wheat leaf rust, and barley powdery mildew, was carried out. No significant fungicidal activities were shown of the synthesized compounds at 100 mg/l.

• The Korean Journal of Pesticide Science
• /
• v.10 no.4
• /
• pp.359-366
• /
• 2006

The protective effect of kresoxim-methyl was investigated on 6 important plant diseases, and the vapour effect of it did on barley and cucumber powdery mildews, respectively. With 2.0 ${\mu}g\;mL^{-1}$ of kresoxim-methyl, its high activities against wheat leaf rust and barley powdery mildew were showed such as 92 and 100%, while activities were very low against rice sheath blight, tomato gray mold, and tomato late blight. In vapour phase control activity of kresoxim-methyl against barley powdery mildew was positively correlated with the applied concentrations, except for azoxystrobin and metominostrobin. With 200 ${\mu}g\;L^{-1}$, its control value was 71.9%. When 1000 ${\mu}g\;m^{-3}$ of kresoxim-methyl in vapour phase was applied on 4 plants of cucumber in a vinyl chamber, 51.1% of control value on kresoxim-methyl-treated cucumber was showed 7 days after the application.

• The Korean Journal of Pesticide Science
• /
• v.4 no.3
• /
• pp.19-26
• /
• 2000

In order to select potent bioactive isolates, 70 Fusarium isolates obtained from soil and 21 plant species were screened by antifungal, insecticidal, herbicidal, and duckweed bioassays after culturing in potato dextrose broth and rice solid media. Eight (11.4%) of the 70 liquid broth cultures showed disease-controlling activities more than 80% against at least one of the 6 plant diseases tested. Fusarium sp. FO-68 isolate exhibited the most potent antifungal activity; it controlled rice blast, wheat leaf rust, and barley powdery mildew with control values more than 95%. Out of 70 solid cultures, 21 (30.0%) controlled at least one plant disease more than 80% and F. equiseti FO-68 isolate showed disease-controlling activities more than 95% against 3 plant diseases such as rice blast, tomato late blight, and wheat leaf rust. As for tile insecticidal activities, 2 liquid and 1 solid cultures showed potent insecticidal activities against pest insects more than 80%, Liquid cultures of F. oxysporum FO-61 and Fusarium sp. FO-80 isolates exhibited insecticidal activities more than 80% against green peach aphid and diamondback moth, respectively. The solid culture of Fusarium sp. FO-510 isolate had 80% insecticidal activity against green peach aphid. However, none of liquid and solid cultures of the 70 Fusarium isolates showed potent herbicidal activities against 10 upland weeds. As the results of duckweed assay, 3 liquid cultures showed 70% growth inhibitory activity at concentrations less than 1.25% of culture supernatants and 9 solid cultures had a potent inhibitory activity against duckweed growth. On the other hand, there was a significant correlation between antifungal activities and herbicidal activities against duckweed of both liquid and solid cultures of tile 70 Fusarium isolates.