• The Plant Pathology Journal
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• v.15 no.1
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• pp.14-20
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• 1999

Twenty isolates of Helminthosporium species were obtained from various grass plants and tested for controlling efficacy on the development of plant diseases. An isolate of Helminthosporium sp. TP-4 was chosen and six antibiotic substances were purified from cultures of the fungus by repeated silica gel column chromatography and preparative thin-layer chromatography. They were identified as ophiobolin a, 6-epiophiobolin A, 3-anhydroophiobolin A, 3-anhydro-6-epiophiobolin A, iphiobolin B, and iphiobolin I mainly by mass spectrometry and nuclear magnetic resonance spectrometry. Ophiobolins inhibited the growth of a grampositive bacterium Streptomyces griseus, but were not active against gram-negative bacteria. They also showed an antifungal activity. In in vivo tests, iphiobolin B exhibited potent controlling activities against rice blast, tomato late blight, and wheat leaf rust with control values more than 90% and 70% at concentration of $500\mu\textrm{m}$/ml and 100 ${\mu}{\textrm}{m}$/ml. Ophiobolin A and 6-epiophiobolin A controlled the development of wheat leaf rust more than 80% at concentrations of 100 /ml and $500\mu\textrm{m}$/ml respectively. 3-Anhydro-6-epiophiobolin A was not active against any plant disease. On the other hand, the A-series ophiobolins other than 3-anhydroophiobolin A showed stronger phytotoxic activity in a leaf-wounding assay using 8 plant species than those of 3-anhydroophiobolin A, ophiobolin B, and ophiobolin I. The results indicate that there is little correlation between antifungal activity and phytotoxicity of ophiobolins.

• Journal of Biosystems Engineering
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• v.34 no.1
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• pp.50-56
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• 2009

Surface plasmon resonance (SPR) biosensor has been used to detect many biochemical reactions, because this label-free sensor has high sensitivity and rapid response. The reactions are monitored by refractive index changes of the SPR biosensor. Iprovalicarb is protective, curative, and eradicative systemic fungicide introduced by Bayer AG in 1999. It has potential far control of downy mildew infesting onion, cucumber, grape and melon, late blight infesting tomato and potato, and anthracnose infesting watermelon and pepper. It is strictly limited to the maximum residue limit. In this study, the applicability of a portable SPR biosensor (Spreeta, Texas instrument, TX, USA) to detect the iprovalicarb residue was examined. The sensor chip was adopted to detect the reaction of iprovalicarb to immobilized iprovalicarb-antibody. The binding of the iprovalicarb onto the biosensor surface was measured by change of the refractive index (RI). Characteristics of the sensor chip including specificity, sensitivity, stability, and reusability were analyzed. In calibration test for seven levels of iprovalicarb concentration (0.32 to 5,000 mg/L) with three replications, a Sigmoidal model with Hill function was obtained between relative RI value and the iprovalicarb concentration with R-square of 0.998. It took 30 minutes to complete a set of detecting assay with the SPR biosensor.

• The Korean Journal of Pesticide Science
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• v.5 no.1
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• pp.1-11
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• 2001

Climate in the year of 2000 was characterized as a long severe drought in tile spring, unusually high and low temperature in summer, two times of typoons, and floods by heavy rains in fall. Rice leaf and panicle blast and bacterial grain rot occurred severely comparing with 1999 and Bipolaris leaf spot spread over tile country. Phytophthora blight and anthracnose in red-pepper became epidemic especially in the late season causing severe yield losses. Tomato fusaruim wilt, CGMMV, powdery mildew, and sudden wilt syndrom of cucurbits and strawberry powdery mildew were also severe in 2000. In garlic, sclerotium rot occurred severely mainly due to the frequent rainfalls in planting time and much snowfalls in 1999's winter. Spring potato had severe infection of viruses due to a long spring drought, and fall potato had high incidence of bacterial soft rot and bacterial wilt due to fall floods by heavy rains. In sweet potato fusarium wilt was the most severe as in other year. Disease incidence of apple and pear trees was rotatively mild compared with previous years. In wheat and barley, Gibberella petch rarely occurred because of spring drought.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.4
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• pp.771-780
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• 2024

In this study, we implemented a real-time pest detection and prediction system for a strawberry farm using a computer vision model based on the YOLOv5 architecture and an Isolation Forest Classifier. The model performance evaluation showed that the YOLOv5 model achieved a mean average precision (mAP 0.5) of 78.7%, an accuracy of 92.8%, a recall of 90.0%, and an F1-score of 76%, indicating high predictive performance. This system was designed to be applicable not only to strawberry farms but also to other crops and various environments. Based on data collected from a tomato farm, a new AI model was trained, resulting in a prediction accuracy of over 85% for major diseases such as late blight and yellow leaf curl virus. Compared to the previous model, this represented an improvement of more than 10% in prediction accuracy.

• The Korean Journal of Pesticide Science
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• v.5 no.3
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• pp.18-25
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• 2001

Ethanol extracts from 46 plants were tested for their fungicidal activity against six plant diseases consisting of Maynaporthe grisea, Rhizoctonia solani, Botrytis cinerea, Phytophthora infestans, Puccinia recondita, and Erysiphe graminis in the greenhouse studies. Strong activity at 5 and 10 mg/pot was produced from the extracts of Helianthus annuus flowers and Zea mays leaves against P. grisea. In a test with B. cineara, extracts of H. annuus leaves, H. annuus flowers, Chrysanthmum coronarium var. spatiosum, Cucurbita moschata seeds, Lycopersicon esculentum, Z. mays, and Z. mays leaves had strong activities at 5 mg/pot. In a test with P. recondita, strong activity was obtained from the extracts of Capsicum frutescens, C. moschata seeds, H. annuus seeds, L. esculentum, and Malva veticillata at 5 mg/pot. Against E. graminis, extracts of Cucumis sativus, H. annuus seeds, Salanum tuberosum, Z. mays, and Z. mays leaves produced strong activities at 10 mg/pot. All the extracts were ineffective against P. infestans and R. solani. Among seven extracts tested, the extracts of H. annuus leaves and flowers were highly effective against all the strains of B. cinerea resistant to carbendazim, procymidone, and diethofencarb. Furthermore, potent fungicidal activity was produced from the extracts of C. coronarium var. spatiosum and C. moschata seeds against the SSR, SRR, and RSR strains of B. cinerea, and Z. mays and Z. mays leaves against SSR and RSR. Extract of L. esculentum showed very strong activity only against RRS of B. cinerea.

• The Korean Journal of Pesticide Science
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• v.7 no.1
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• pp.51-57
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• 2003

For the purpose of a development of new agrochemical fungicides, new compound 4 in which 1,3-thiazoline scaffold as well as urea moiety in the structure was designed through molecular modification of lead compound, 2-imino-1,3-thiazone based on isosterism. The reaction of N-alkylthiourea 5 and bromoacetonitrile in ethanol gave 2,4-diimino-1,3-thiazolidine hydrobromide 6 regioselectively, which was treated with isocyanates gave the corresponding 8 which is tautomer of 4. Antifungal screening (in vivo) of the synthesized compound 8 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. Antifungal activities against rice blast of the compound 8 were weaker than those of 2-phenylimino-1,3-thiazoline 1. Some compounds showed weak antifungal activities against wheat leaf rust.

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

• The Korean Journal of Pesticide Science
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• v.3 no.1
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• pp.20-28
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• 1999

Chloronicotinyl derivatives were synthesized by substitution of amino in 3-pyridylmethylamine with phosphite groups and their insecticidal and fungicidal activities were determined. At 500 ppm, compound 4 with methyl and butyl group in phosphonate and compound 5, 6, 7, and 8 with two butyl, 2,2,2-trifluorotehtyl, 2-ethylhexyl, phenyl, respectively, in phosphonate showed 90% insecticidal activities against brown plant-hopper (Nilaparvate lugens). These compounds showed, however, poor insecticidal activities against diamond-back moth (Plutella xylostella) and two-spotted spider mite (Tetranychus urticae) (<65%), suggesting that insecticidal activity of chloronicotinyl derivatives containing phosphorus moieties are species-dependent. Newly synthesized chloronicotinyl derivatives with halogen and/or heterocycle (compound $10{\sim}21$) did not show insecticidal activities. We also determined fungicidal activity of the synthesized chloronicotinyl derivatives against rice sheath blight (Pyricularia grisea), cucumber gray mold (Bortytis cinerea), tomato late blight (Phytophthora infestans), wheat leaf rust (Puccinia recondita), and barley powdery mildew (Erysiphe graminis). Compound 10 with butyl and 4-nitrophenyl in phosphonate at 10 ppm showed 85% fungicidal activity against rice blast, suggesting that chloronicotinyl derivatives containing phosphorus moieties could be developed as a fungicidal agent of a novel chemical structure.

• The Korean Journal of Pesticide Science
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• v.5 no.2
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• pp.26-32
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• 2001

[ ${\alpha},{\beta}$ ]-Unsaturated carboxamides 12 with trifluromethylated dihydro-1,4-dithiins were synthesized for the purpose of development of new agrochemical fungicide. Chlorination of trifluoromethylated ${\beta}$-ketoester 4 followed by tile reaction with 1,2-ethanedithiol gave intermediate 1,4-dithiane 9. Without purification of 9 substitution of hydroxy by chlorine followed by dehydrochlorination in the presence of triethylamine afforded trifluoromethylated dihydro-1,4-dithiin ethyl ester 7. Activation of the hydroxy of the carboxylic acid 10 obtained from the hydrolysis of 7 and then reacted with various amines gave the corresponding trifluoromethylated dihydro-1,4-dithiin carboxamides. Antifungal screening (in vivo) against typical plant diseases, Rice Blast, Rice Sheath Blight, Cucumber Gray Mold, Tomato Late Blight, Wheat Leaf Rust, and Barley Powdery Mildew of the synthesized compounds was carried out. As a result, most of the compounds shlowed weak antifungal activities and some compounds in which isopropyl group was substituted in meta of the phenyl showed antifungal activity (99%) at 250 ppm against the disease Wheat Leaf Rust.

• Microbiology and Biotechnology Letters
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• v.33 no.1
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• pp.16-23
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• 2005

In order to develop a new microbial fungicide using endophytic bacteria for the control of anthracnoses occurring on various crops, a total of 260 bacterial strains were isolated from fresh tissues of 5 plant species. After they were cultured in broth medium, their antifungal activities were tested for in vivo antifungal activity against cucumber anthracnose caused by Colletotrichum orbiculare. As the results, liquid cultures of 28 strains showed potent antifungal activities more than $90\%$ against cucumber anthracnose. At 3-fold dilutions of liquid cultures, 18 strains inhibited the development of cucumber anthracnose of more than $70\%$. They were further tested for in vivo antifungal activity against red pepper anthracnose caused by C. coccodes and in vitro antifungal activity against C. acutatum, a fungal agent causing red pepper anthracnose. Among 18 strains, a bacterial strain EB215 isolated from cucumber roots displayed the most potent antifungal activity against Colletotrichum species. It was identified as Burkholderia cepacia based on its physiological and biochemical characteristics, Biolog test and 16S rDNA gene sequence. It also controlled effectively the development of rice blast (Magnaporthe grisea), rice sheath blight (Corticium sasaki), tomato gray mold (Botrytis cinerea), and tomato late blight (Phytophthora infestans). Studies on the characterization of antifungal substances produced by B. cepacia EB215 are in progress.