• International Journal of Industrial Entomology and Biomaterials
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• v.8 no.2
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• pp.201-205
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• 2004

During the routine survey, the mortality of mulberry seedlings was noticed due to damping-off disease. The disease recognized by rotting of emerged seedlings near the soil line (just below the soil level) resulting in collapse of the seedlings. Two fungi were isolated from affected samples and identified as Alternaria alternata (Fr.) Keissler and Fusarium solani (Mart.) Sacc. Both the fungi were found to be responsible in causing pre and post emergence damping-off of seedlings in mulberry. For management of the disease, an experiment was conducted using fungicides. These fungicides were applied as seed treatment; soil drenching and foliar spray alone and in combination. Among the different treatments, integration of seed treatment and soil application of Dithane M-45 (Mancozeb 75% WP) + Bavistin (Carbendazim 50% WP) followed by foliar spray of these fungicides (after 35 days of sowing) resulted in better survivability of seedlings (93.3 %) on $90^th$ day and controlled the pre and post emergence damping off by 100 and 89.5%, respectively over the check.

• Mycobiology
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• v.38 no.4
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• pp.316-320
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• 2010

Leaf spot and blight disease was observed on two-year-old seedlings of Dendropanax morbifera (Korean name: Hwangchil tree) during July of 2008 in Jindo Island, Korea. Symptoms included yellow-brown to dark brown irregularly enlarged spots frequently located along the veins of leaves. The lesions were often surrounded by chlorotic haloes. Severe leaf blight and subsequent defoliation occurred when conditions favored disease outbreak. The causal organism of the disease was identified as Alternaria panax based on morphological characteristics and sequence analysis of the internal transcribed spacer region of rDNA. A. panax isolates induced leaf spots and blight symptoms not only on D. morbifera but also on the other members of Araliaceae tested. This is the first report of foliar blight caused by A. panax on D. morbifera.

• Research in Plant Disease
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• v.22 no.2
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• pp.81-93
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• 2016

Out of plant-associated bacteria, certain plant growth-promoting bacteria (PGPB) have been reported to increase plant growth and productivity and to elicit induced resistance against plant pathogens. In this study, our objective was to broaden the range of applications of leaf-colonizing PGPB for foliar parts of road tress and pepper. Total 1,056 isolates of endospore-forming bacteria from tree phylloplanes were collected and evaluated for the enzymatic activities including protease, lipase, and chitinase and antifungal capacities against two fungal pathogens, Colletotrichum graminicola and Botrytis cinerea. Fourteen isolates classified as members of the bacilli group displayed the capacity to colonize pepper leaves after spraying inoculation. Three strains, 5B6, 8D4, and 8G12, and the mixtures were employed to evaluate growth promotion, yield increase and defence responses under field condition. Additionally, foliar application of bacterial preparation was applied to the road tress in Yuseong, Daejeon, South Korea, resulted in increase of chlorophyll contents and leaf thickness, compared with non-treated control. The foliar application of microbial preparation reduced brown shot-hole disease of Prunus serrulata L. and advanced leaf abscission in Ginkgo biloba L. Collectively, our results suggest that leaf-colonizing bacteria provide potential microbial agents to increase the performance of woody plants such as tree and pepper through spray application.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.89.2-90
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• 2003

Potato late blight, caused by Phytophthora infestans, is one of the important diseases in potato cultivation areas. Though the incidence of late blight was depend on the inoculums and climatic condition In each fields, the foliar blight was reached to 100％ under the severe disease pressure condition in 2003. Outbreak of foliar blight was concentrated from May and July and evaluation of ten fungicides to control of late blight was made at Daekwallryoung area in potato fields. Based on the company recommendation, those fungicides were applied by a sprayer at the recommended rates on a weekly application schedule. Effect of ten fungicides on foliar blight was based on area under disease progress curve (AUDPC). Across all fungicides was reduced by 77％ in AUDPC and dimethomorph was reduced by 92％ in AUDPC during the same period, respectively. Those fungicide were inhibited the mycelial growth of isolate with different rate in chemical amended medium and several fungicides were completely limited the growth of isolate.

• Research in Plant Disease
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• v.22 no.3
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• pp.202-207
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• 2016

Rice bacterial blight and blast are devastating rice diseases in worldwide. Riboflavin, vitamin B2, is an essential nutrient for human health, and is known to be as a growth regulator and as a plant defense activator against pathogens in plants. In this study, we investigated possibility of increasing internal vitamin B contents and inducing resistances against rice diseases by external foliar application of a riboflavin-based formulator called BioDoctor. In planta bioassay indicated that pretreatment of the foliar application of 1,000-fold or 500-fold diluted BioDoctor significantly induced disease resistance against rice blast and bacterial blight. In addition, about four fold higher levels of riboflavin contents were detected in the BioDoctor treated rice grain and stem compared to those of untreated rice. Our results indicated that foliar application of the riboflavin has a great potential to control plant diseases and to enhance internal vitamin contents in rice.

• The Korean Journal of Mycology
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• v.19 no.2
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• pp.128-135
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• 1991

Diethyl ether soluble toxin produced by H. sativum had the characteristics of helmin­thosporal as based on UV, GC-MS, and chemical analysis, but was not a helminthosporaI. It was speculated that it was a polymer of helminthosporal. It stimulated the productions of reducing sugar in the barly endosperm like gibberellic acid, but acted in the responses on the barley roots and coleoptiles like gibberellic acid. It seemed to be involved in Foliar and Root rot diseases with host specificity, based on the analysis of linear regression.

• International Journal of Industrial Entomology and Biomaterials
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• v.12 no.1
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• pp.35-39
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• 2006

Fifty-six indigenous and twenty nine exotic mulberry varieties were screened against powdery mildew, Myrothecium leaf spot, Pseudocercospora leaf spot, sooty mold and bacterial leaf spot for a period of three years under field condition. The percent disease index (PDI) was recorded during peak season of the foliar diseases. Out of eighty-five varieties studied, ten varieties were highly resistant and eight were resistant to powdery mildew; six varieties were immune and seventy-eight varieties were highly resistant to Myrothecium leaf spot; sixty varieties were highly resistant and 21 were resistant to Pseudocercospora leaf spot; forty four varieties were highly resistant to sooty mold and two varieties were immune and fifty-eight were highly resistant to bacterial leaf spot. Lowest cumulatative disease index was observed in M. multicaulis (7.28) followed by Thailand lobed (7.85) and Italian mulberry (8.06).

• Journal of Microbiology and Biotechnology
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• v.26 no.9
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• pp.1542-1550
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• 2016

This is the first report that paromomycin, an antibiotic derived from Streptomyces sp. AG-P 1441 (AG-P 1441), controlled Phytophthora blight and soft rot diseases caused by Phytophthora capsici and Pectobacterium carotovorum, respectively, in chili pepper (Capsicum annum L.). Chili pepper plants treated with paromomycin by foliar spray or soil drenching 7 days prior to inoculation with P. capsici zoospores showed significant (p < 0.05) reduction in disease severity (%) when compared with untreated control plants. The disease severity of Phytophthora blight was recorded as 8% and 50% for foliar spray and soil drench, respectively, at 1.0 ppm of paromomycin, compared with untreated control, where disease severity was 83% and 100% by foliar spray and soil drench, respectively. A greater reduction of soft rot lesion areas per leaf disk was observed in treated plants using paromomycin (1.0 μg/ml) by infiltration or soil drench in comparison with untreated control plants. Paromomycin treatment did not negatively affect the growth of chili pepper. Furthermore, the treatment slightly promoted growth; this growth was supported by increased chlorophyll content in paromomycin-treated chili pepper plants. Additionally, paromomycin likely induced resistance as confirmed by the expression of pathogenesis-related (PR) genes: PR-1, β-1,3-glucanase, chitinase, PR-4, peroxidase, and PR-10, which enhanced plant defense against P. capsici in chili pepper. This finding indicates that AG-P 1441 plays a role in pathogen resistance upon the activation of defense genes, by secretion of the plant resistance elicitor, paromomycin.

• Mycobiology
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• v.45 no.4
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• pp.409-420
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• 2017

Foliar sprays of three plant resistance inducers, including chitosan (CH), potassium sorbate (PS) ($C_6H_7kO_2$), and potassium bicarbonates (PB) ($KHCO_3$), were used for resistance inducing against Erysiphe cichoracearum DC (powdery mildew) infecting okra plants. Experiments under green house and field conditions showed that, the powdery mildew disease severity was significantly reduced with all tested treatments of CH, PS, and PB in comparison with untreated control. CH at 0.5% and 0.75% (w/v) plus PS at 1.0% and 2.0% and/or PB at 2.0% or 3.0% recorded as the most effective treatments. Moreover, the highest values of vegetative studies and yield were observed with such treatments. CH and potassium salts treatments reflected many compounds of defense singles which leading to the activation power defense system in okra plant. The highest records of reduction in powdery mildew were accompanied with increasing in total phenolic, protein content and increased the activity of polyphenol oxidase, peroxidase, chitinase, and ${\beta}$-1,3-glucanase in okra plants. Meanwhile, single treatments of CH, PS, and PB at high concentration (0.75%, 2.0%, and/or 3.0%) caused considerable effects. Therefore, application of CH and potassium salts as natural and chemical inducers by foliar methods can be used to control of powdery mildew disease at early stages of growth and led to a maximum fruit yield in okra plants.

• The Plant Pathology Journal
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• v.18 no.2
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• pp.93-97
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• 2002

Aster yellows phytoplasma-infected chrysanthemums showing stunt, rosette, and excessive branching were treated with a foliar spray of 400 mg/I oxytetracycline at three-day interval for 1,2,3 and 4 months. Two months after the final treatment, new shoots from the recovered chrysanthemums showed the recurrence of the disease symptoms. However, cuttings from chrysanthemums treated with oxytetracycline did not express any photoplasma infection symptoms for more than 10 months. Also, chrysanthemums dipped in 100 mg/I oxytetracycline solution combined with a foliar spray of 400 mg/I oxytetracycline for 4 weeks showed the same results. Using an electron microscope, ultrathin sections of leaf midribs of chrysanthemum cuttings treated with oxytetracycline for 4 months did not show phytoplasma bodies 10 months after treatment. Nucleic acids from chrysanthemums, which did not express phytoplasma infection symptoms for more than 10 months, did not amplify 16S rRNA gene of phytoplasma by polymerase chain reaction. These results may have implications in the propagation of phytoplasma-free healthy stocks for a wide range of plant species.