• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.103.2-104
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• 2003

Ginseng (Panax ginseng) is one of the most widely cultivated medicinal herbs in Korea. During 3 or 5 years cultivation of ginseng, yield losses can reach as high as 30-60％ due to numerous diseases in Korea. Among 106 Bacillus strains isolated from various plant internal roots, we selected three promising biocontrol agents by screening against root rot caused by Cylindrocarpon destructan in a greenhouse. Preinoculation of selected isolates to seed or one-year-old root resulted in stimulation of shoot and/or root growth of seedlings, and control of root rot in infested soils with Cylindronrpon destructans (P=0.05). Furthermore, drenching of selected isolates on seedling-growing pots reduced the incidence of Phytophthora blight when the seedlings were challenged with zoospores of Phytophthora cactorum (P=0.05). However, isolates B1141 and B1142 did not show any antifungal activity against various soilborne pathogens while B1146 did in vitro. Our results provide an insight that rhizobacteria can induce resistance against various plant diseases on ginseng even if any resistant breeds have been unknown on ginseng yet.

• Asian-Australasian Journal of Animal Sciences
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• 제7권4호
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• pp.547-554
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• 1994

This paper presents the effects of supplementary feeding and internal parasites on the growth rates of female weaner goats raised under improved management. A completely randomized $3{\times}3{\times}2$ factorial design was used. Factors were genotype (Thai native: TN, 75% TN $\times$ 25% Anglo-Nubian: An and 50% TN $\times$ 50% AN), feeding grazing only, low (1.0% BW/d) and high (1.5% BW/d) supplementation and parasite control (undrenched and drenched). It was shown that native goats had significantly (p<0.05) higher growth rates than did the cross-bred goats from 12-24 weeks of the trial. The growth rate of goats grazing improved pasture depended on the amount of concentrate offered as a supplement. There was no significant difference in growth rates between undrenched and drenched goats. There was no interaction effect on growth rates between the treatments. Drenched goats had significantly (p<0.01) lower egg counts per gram of gastro-intestinal nematode than did undrenched goats. There was no significant difference between the treatments for blood constituents (total protein, haemoglobin, packed cell volume, eosinophils, lymphocytes, monocytes and basophils).

• The Plant Pathology Journal
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• 제29권4호
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• pp.418-426
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• 2013

Pseudomonas isolates from different crop plants were screened for in vitro growth inhibition of Phytophthora capsici and production of biosurfactant. Two in vivo experiments were performed to determine the efficacy of selected Pseudomonas strains against Phytophthora blight of pepper by comparing two fungicide treatments [acibenzolar-S-methyl (ASM) and ASM + mefenoxam]. Bacterial isolates were applied by soil drenching ($1{\times}10^9$ cells/ml), ASM ($0.1{\mu}g$ a.i./ml) and ASM + mefenoxam (0.2 mg product/ml) were applied by foliar spraying, and P. capsici inoculum was incorporated into the pot soil three days after treatments. In the first experiment, four Pseudomonas strains resulted in significant reduction from 48.4 to 61.3% in Phytophthora blight severity. In the second experiment, bacterial treatments combining with olive oil (5 mL per plant) significantly enhanced biological control activity, resulting in a reduction of disease level ranging from 56.8 to 81.1%. ASM + mefenoxam was the most effective treatment while ASM alone was less effective in both bioassays. These results indicate that our Pseudomonas fluorescens strains (6L10, 6ba6 and 3ss9) that have biosurfactant-producing abilities are effective against P. capsici on pepper, and enhanced disease suppression could be achieved when they were used in combination with olive oil.

• 식물병과 농업
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• 제5권2호
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• pp.90-94
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• 1999

Effect of inoculum concentration inoculation method and plant age on development of clubroot disease of Chinese cabbage seedling were examined in growth chambers. Root galls were developed at the concentration of 105 resting spore or above per ml of incoulum and as the inoculum concentration became higher rate of development of root galls was faster. In the plants with root gall development fresh weight of above ground parts was reduced to 30-44% of that of healthy plants but root weight increased by 4-10 times. Growth of diseased plants was greatly reduced as compared to healthy plants. Planting in the diseased soil as a inoculation method was most effective for disease development showing uniform infections but time of initial root gall development was delayed by root soaking inoculation. Some plants inoculated by soil drenching method did not develop root galls. However root gall enlargement after its initial formation did not differ greatly among inoculation methods. Nine-day-old seedlings showed poor development of root gall but 16-days-old seedlings was found to be most adequate for inoculation for gall development.

• The Plant Pathology Journal
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• 제16권3호
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• pp.156-161
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• 2000

A wilt disease occurred on greenhouse-grown eggplants at Yeojoo, Korea in 1997. The wilted eggplants had leaves with gradual yellowing, interveinal necrosis, and marginal crinkling. Vascular tissues of diseased stems were discolored, turned black, and microsclerotia developed at the base of stems. The disease progressed from lower parts of the plants upward. Fungal isolates from discolored vascular tissues were initially whitish to cream color on potato-dextrose agar (PDA) plate, which later turned black due to the formation of microsclerotia. Conidiophores were erect, hyaline, verticillately branched, and had 3 or 4 phialides arising at each node. Phialides were hyaline, arranged in whorls, and measured as 17.5-32.5 x 2-3$\mu\textrm{m}$. Conidia were hyaline, ellipsoidal to sub-cylindrical, mainly one-celled, and measured as 5-8.8 x 2-4$\mu\textrm{m}$. Conidia were borne in small clusters at the tips of phialides. Microsclerotia formed on PDA plates, and consisted of globular cells that formed irregular masses of various shapes. Chlamydospores were absent. Based on these cultural and morphological characteristics, the fungus was identified as Verticillium dahliae Klebahn. Pathogenicity tests by root cutting, root dipping or soil drenching resulted in similar symptoms observed in the naturally infected eggplants. This is the first report on occurrence of Verticillium wilt of eggplant in Korea.

• The Plant Pathology Journal
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• 제29권1호
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• pp.87-92
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• 2013

This study was conducted to determine the Phytophthora rot resistance of 514 accessions of watermelon germplasm, Citrullus lanatus var lanatus. About 46% of the 514 accessions tested were collections from Uzbekistan, Turkey, China, U.S.A., and Ukraine. Phytophthora capsici was inoculated to 45-day-old watermelon seedlings by drenching with 5 ml of sporangial suspension ($10^6$ sporangia/ml). At 7 days after inoculation, 21 accessions showed no disease symptoms while 291 accessions of susceptible watermelon germplasm showed more than 60.1% disease severity. A total of 510 accessions of watermelon germplasm showed significant disease symptoms and were rated as susceptible to highly susceptible 35 days after inoculation. The highly susceptible watermelon germplasm exhibited white fungal hyphae on the lesion or damping off with water-soaked and browning symptoms. One accession (IT032840) showed moderate resistance and two accessions (IT185446 and IT187904) were resistant to P. capsici. Results suggest that these two resistant germplasm can be used as a rootstock and as a source of resistance in breeding resistant watermelon varieties against Phytophthora.

• The Plant Pathology Journal
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• 제23권1호
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• pp.26-30
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• 2007

Phosphorous acid is known to effectively control various Oomycetes diseases. The phosphoric acid moves upward and downward through the xylem and phloem in plants. The sustainable forms of the slow releasing chemical in rhizosphere would be ideal to be up-taken by plants. Therefore, we developed a new system for phosphorous acid formulation using a carrier coated with polysaccharides. When the product was applied in rhizosphere, the adequate amount of phosphorous acid was consistently released up to 4 weeks in rhizosphere soils. While soil drenching with phosphorous acid at 1,000 ${\mu}g/ml$ and metalaxyl at 150 ${\mu}g/ml$ were not effective to control pepper Phytophthora blight for 4 weeks, direct application of our formulation product around basal stem of pepper plants resulted in excellent disease control effect against Phytophthora blight over 4 weeks. The application of 4 g of our product per plant was optimum to control the disease, and 8 g product/plant did not cause phytotoxicity. Based on the results, we conclude that the applications of the formulation product once or twice during cropping season can control Phytophthora diseases on various crops.

• 한국응용곤충학회지
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• 제60권2호
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• pp.201-202
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• 2021

검거세미밤나방(Agrotis ipsilon)은 세계적으로 중요한 나비목 해충으로 유충이 토양 속에 서식하며 다양한 작물을 가해하기 때문에 생물검정에 어려움이 많다. 본 연구에서는 검거세미밤나방에 대한 간이생물검정법을 이용해 배추를 가해하는 검거세미밤나방의 시판 살충제에 대한 감수성을 검정하였다. 시험결과, 토양혼화처리제 6종, 토양관주처리제로 8종이 90% 이상의 살충활성을 보였다.

• The Plant Pathology Journal
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• 제38권5호
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• pp.513-521
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• 2022

Our study was carried out to determine the control efficacy of sodium hypochlorite (NaOCl) for violet root rot caused by Helicobasidium mompa in apple. The experiment was conducted in the farm located at Chungbuk province in South Korea from 2014 to 2016. When infected apple trees were treated at least two or three times with 31.25 and 62.5 ml/l available chlorine content in NaOCl, it greatly increased the rooting of rootstock, and restored the tree crown density by 44.4-60.5%. In addition, the number of commercial fruit setting was increased by 54.3-64.5%, and the total starch content in shoots was significantly higher than other non-treated apple trees. However, the untreated disease control and thiophanate-methyl WP treated trees showed the symptom of dieback. Therefore, our results indicate that the drenching treatment of NaOCl with 31.25-62.5 ml/l available chlorine content more than two times from late fall to early spring could effectively control the violet root rot and recover tree vigor up to 60%.

• Asian-Australasian Journal of Animal Sciences
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• 제8권3호
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• pp.241-247
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• 1995

The aim of the present study was to investigate the effect of internal parasites on growth rates of Thai Native (TN) and crossbred (75% TN $\times$ 25% Anglo-Nubian, AN and 50% TN $\times$ 50% AN) goats (undrenched, drenched every 3 weeks or at 9 weeks) in village environments in southern Thailand in a humid tropical climate. There was no significant (p > 0.05) difference in growth rate ($g/kg^{0.75}/d$) between the genotypes during unsupplemented grazing (0-64 days of the experimental period). However, during supplementary feeding (64-127 days) and throughout the period (0-127 days) TN goats had significantly (p < 0.01) lower growth rates compared with 75% TN $\times$ 25% AN and 50% TN $\times$ 50% AN goats. There was no (p > 0.05) significant difference in growth rates between 75% TN $\times$ 25% AN and 50% TN $\times$ 50 % AN goats. The growth rates of goats drenched every 3 weeks were significantly (p < 0.01) higher than those undrenched or drenched at 9 weeks. The results of this study also indicate that drenching alone did not result in increased weight gain except when the nutritional status was also improved. Parasitic infection affected some blood constituents, such as pack cell volume, haemoglobin, total protein and albumin. This resulted in lower growth rates for control groups and goats drenched at 9 weeks compared to those of goats drenched every 3 weeks.