• Korean journal of applied entomology
• /
• v.47 no.1
• /
• pp.17-22
• /
• 2008

This survey was conducted from 1992 to 2005 in the major apple producing districts in southern part of South Korea including $4{\sim}8$ cities, to know the occurrence and damage level of two major pests, Carposina sasakii and Grapholita molesta that attack apple fruit. The fruit damage by G. molesta during the harvest period ranged from 0.02 to 1.64%. A tendency of higher damage of G. molesta was observed after 1997 compared with the previous years. The other hand, the fruit damage by C. sasakii was 0.02 to 1.30%, and the damage level was very low with fruit damage of < 0.3% except 1998. The orchard infested with G. molesta was 13 to 71 %, while 12 to 57% with C. sasakii. The rates of orchards where fruit damage by G. molesta was found were higher than those by C. sasakii after 1997. The tendency of fruit damage rates in the orchard where the most fruit damage was found was same with the trend of orchard rates infested with the pests. The maximum damage rate by G. molesta was 20.0% in 2005, while 4.5% by C. sasakii in 1998. The damaged shoot rates by the first generation G. molesta was $0.1{\sim}8.1%$, and it had a positive correlation with the rates of fruit damage during the harvest period. Consequently, it is concluded that G. molesta is dominant species compared with C. sasakii in commercial apple orchards recently.

• Journal of Plant Biotechnology
• /
• v.42 no.3
• /
• pp.239-244
• /
• 2015

Calanthe striata f. sieboldii Decne. ex Regel is a terrestrial orchid with beautiful flowers arranged in racemose inflorescences. This species is threatened due to over-collection and loss of suitable habitats. Asymbiotic germination is useful in the conservation efforts to re-establish plants in the wild, and for commercial propagation. In this study, we investigate the effects of sodium hypochlorite (NaOCl), three types of culture media (Phytomax Orchid Maintenance - POM, Seed Germination Maintenance - SGM, and Murashige and Skoog 1962 - MS), and plant growth regulators on embryo swelling, protocorm formation, and embryo diameter of C. striata f. sieboldii. Treatment with 1% NaOCl for 30 min greatly enhanced embryo swelling (28.3%), embryo diameter ($205.8{\mu}m$), and embryo protocorm formation (54.8%) compared to seeds without NaOCl treatment (embryo swelling 8.5%, embryo diameter $14.6{\mu}m$, and protocorm formation 13.4%) on POM medium. Protocorm formation on POM medium supplemented with 1.0 mg/L N6-benzyladenine (BA) (95.6%) was better than the control (54.5%). Additionally, the effects of activated charcoal (AC) and sucrose on seedling growth in in vitro culture were examined. The protocorm converted into healthy plants with well-developed shoot primordia on the POM medium with AC and sucrose. The most suitable conditions for seedling growth after 10 weeks of culture were the POM medium with AC or sucrose. These results show effective asymbiotic seed germination and in vitro seedling growth of C. striata f. sieboldii.

• Korean journal of applied entomology
• /
• v.32 no.3
• /
• pp.338-347
• /
• 1993

The study was to investigate the bionomics, host plants, and oviposition preference of Hishimonus sellatus Uhler. It has 5 generations under natural conditions and the peak of the 3rd generation was observed about mid and late August. Its average developmental durations were 80 days in spring, 69 days in summer, and 77.8 days in autumn. The lengths of each stage were 0.8mm in eggs, 0.9mm in 1st instar, 1.4mm in 2nd instar, 2.1mm in 3rd instar, 2.5mm in 4th instar, 3.2mm in 5th instar, 4.1mm in female, and 3.8mm in male. Hishimonus sellatus overwintered as egg in Morus alba, Humulus japonicus, and Zizyphus jujuba begining mid October, and attacked the shoot of M. alba and H. japonicus about mid and late May, migrated to the Zizyphus jujuba from late June to early July. Female oviposites 32~62 eggs into epidermis of shoot, vagina and vein during their life. The preferred host plants of H. sellatus were Humulus japonicus, Morus alba, Zizyphus jujuba, and ligustrum obtusifolium. Highly preferable oviposition site was H. japonicus, M. albal, Z. jujuba, and L. obtusifolium, etc. On audlt longevity, the host plants as H. japonicus, M. alba, and Z. jujuba were 43$\pm$2 days and A. brevipedenculata, C. mimosoides, L. obtusifolium, V. rosa, A. sinicus and, A. graveolens were more than 25 days, and other host plants were less than 20 days.

• Korean journal of applied entomology
• /
• v.52 no.1
• /
• pp.45-51
• /
• 2013

Tropical plants of mango(Mangefera indica), dragon fruit(Hylocereus undatus), and atemoya(Annona cherimola ${\times}$ A. squamosa) are cultivated in Jeju, Korea. A pest survey on those tropical fruits was conducted from 2008 to 2011. Major pests of Mango were thrips, aphid, mealybug, and lepidoptera species. Thrips palmi and Scirtothrips dorsalis were the most important pests in mango fields. T. palmi mainly injured the leaf but S. dorsalis injured the leaf and fruit. Lepidoptera mango pests injured leaves but some larva of Adoxophyes honmai injured fruit surface around the stem. Aphid pests, Aphis gossypii and Myzus persicae, injured the shoots and Pseudococcus kraunhiae occurred on the stem and fruit. Ant species, A. gossypii, and S. litura, were important pests on dragon fruit. Ants and aphid occurred and injured the stem, flower, and fruit. Spodoptera litura larva severely injured the stem. Among the atemoya pests, S. litura and Homona magnanima caused severe damage.

• Korean Journal of Plant Resources
• /
• v.18 no.3
• /
• pp.382-389
• /
• 2005

This study was conducted to establish the system of effective in vitro propagation by various explant sources culture of Bippeastrum hybridum Hort, 'Dazzler'. We tested the effects of optimal explant source, plant growth regulators on bulblet formation and plant regeneration. Callus was readily produced on the different tissues excised from floral buds whereas, bulbs and shoots were formed only on pedicel explants as compared with anthers, styles and ovaries. Pedicel is the best optimal explant for in vitro propagation. Two distinct pathways, organogenesis through callus and direct bulblet formation, could be recognized in pedicel culture. Up to the $80-100\%$ of bulblet formation and shoot organogenesis from the pedicel in fifteen days before anthesis were effectively induced by MS medium supplemented with 0.5 mg/L NAA and 1.0 mg/L BA. Plantlet regeneration was successfully achieved from pedicel-derived callus, via shoot bud induction or direct bulblet formation. The bulblets with blooming flower were produced within 2 years.

• Korean Journal of Plant Resources
• /
• v.19 no.2
• /
• pp.315-322
• /
• 2006

This experiment was conducted to investigate the induction rate of callus and antioxidative activity of rosemary and lavender. Callus induction rate of rosemary was 92% and 94% at 0.5mg/L and 1.0mg/L of 2,4-D in the media, respectively. The antioxidative activities of rosemary appeared differently according to the callus cultured under various concentrations of plant growth regulators. The strongest effect was observed at 0.1mg/L of 2,4-D extract, with $43{\pm}1.5{\mu}g/mL$ of an RC50 value. Callus induction rate of lavender was 98% and 99% at 1.0mg/L of 2,4-D and 1.0mg/L of NAA in the media, respectively. The regeneration rate of roots lavender was 85% at 1.0mg/L of NAA in the media. Antioxidative activities of lavender appeared diffently according to the callus cultured under plant growth regulators. The strongest effect was observed in 0.1mg/L of 2,4-D extract, with $37.6{\pm}0.9{\mu}g/mL$ of an RC50 value, which could be compared with value of leaf.

• Horticultural Science & Technology
• /
• v.32 no.4
• /
• pp.454-462
• /
• 2014

This study was carried out to determine the effect of tree height on light transmission, spray penetration, tree growth performance, fruit quality attributes, and labor productivity in the slender-spindle system of 'Hongro'/M.9 apple trees. With increasing tree height, the light penetration into the internal parts of the canopy decreased, especially in the lower canopy. Leaf area index (LAI) increased with increasing tree height, thereby leading to a reduction in the extent of spray penetration into the interior of the canopy. With increasing tree height, shoot growth was more vigorous but produced slender shoots in the upper canopy compared to the lower canopy. Although the soluble solid content and coloration of fruit decreased, there was no difference in fruit firmness and acidity. In addition, the number of final fruit set increased, although the production of large fruit (> 305 g) decreased. The increase in tree height also significantly increased the labor required for practices such as thinning of flowers and fruits, pruning, and harvesting. Nevertheless, this problem of increased in labor input in taller trees would was eased by use of a mechanical lift. Utilizing a lift for thinning the flowers of trees 4.5 m in height saved 14.6 min per tree, compared to the use of ladder. Therefore, it is highly considerable that in order to enhance light transmission and fruit coloration, light conditions should be improved in the internal tree canopy of slender-spindle systems.

• Childhood Kidney Diseases
• /
• v.2 no.2
• /
• pp.161-168
• /
• 1998

Purpose : Lots of congenital anomalies of urinary tract including hydronephrosis are detected in fetus and neworn by popular use of prenatal ultrasonography. But there are little data available in Korea about natural course of hydronephrosis diagnosed antenatally by ultrasonography. So we intended to help management of these patients by analizing the follow up data of the neonates with hydronephrosis diagnosed antenatally. Methods : We evaluated 22 patients with neonatal hydronephrosis(33 renal units) who were diagnosed prenatally and confirmed postnatally. Especially patients with suspected ureteropelvic junction obstruction were followed regulary with renal ultrasonography and diuretic renography for 8-24 months. Results : 1) The etiologies of neonatal hydronephrosis diagnosed prenatally were suspected ureteropelvic junction obstruction($69.9\%$), vesicoureteral reflux($15.1\%$), primary megaureter($3.0\%$), double ureter with ureterocele($3.0\%$), ureteral stricture($3.0\%$), multicystic dysplastic kidney(3.0$\%$), and ureterovesical junction obstruction(3.0$\%$). 2) The follow up results of 23 renal units of suspected ureteropelvic junction obsruction: Except 4 renal units with palpable abdominal mass, of the remained 19 renal units, 14 units($73.6\%$) were improved spontaneously, 3 units($15.7\%$) remained stable, only2 units($10.5\%$) were aggravated. Conclusion : We concluded that in most cases of hydronephrosis there is no need for immediate surgery, and that nonoperative approach, using serial ultrasonography and diuretic renogram, is safe management of neonatal hydronephrosis diagnosed anteratally.

• Research in Plant Disease
• /
• v.24 no.1
• /
• pp.41-51
• /
• 2018

Since fire blight disease on apple and pear was produced in Korea in 2015, there were no registered chemicals to control against this disease. Instead, several antibacterial chemicals that were registered for other bacterial diseases such as soft rot and bacterial spot have been authorized by Rural Development Administration (RDA). However, these chemicals are not tested efficacy for fire blight disease except damage by those treatments on apple and pear in Korea. Thus, we evaluated efficiency using in vitro and in planta assays of antibacterial chemicals such as antibiotics and copper compounds including kasugamycin, oxytetracycline, oxolinic acid and streptomycin, and copper hydroxide, copper sulfate, oxine copper and tribasic copper sulfate, respectively. We also tested two kinds of biological agents. As expected, significant antibacterial effect was observed in vitro test of both antibiotics and copper-based chemicals. In planta test based on disease severity including ooze and water-soaked formation on immature pears, bacterial populations on blooms, and blight lesion formation in artificially inoculated shoots, kasugamycin, oxytetracycline and streptomycin have been shown the most efficiency among tested antibiotics. Four copper-based chemicals tested in this study, control effects are little bit lower than agricultural antibiotics but they seem to be available to use in terms of winter season. Biocontrol agents were also shown possibility to treat in eco-friendly farms. In addition, there are no antibiotic resistance genes in Korean isolates against antibiotics, which were selected for suppression of fire blight in this study.

• Korean Journal of Plant Tissue Culture
• /
• v.27 no.2
• /
• pp.109-115
• /
• 2000

Effects of the heavy-ion ($^{14}$ N or $^{20}$ Ne) beam irradiation on the response of anthers, growth of calli, germination of seeds, and the early growth after the germination of tobacco (Nicotiana tabacum L. cv. BY-4) were investigated. Anthers precultured for 10 days before the irradiation became brown without callus or shoot induction over 20 Gy of $^{14}$ N and $^{20}$ Ne ion beam irradiation. Relative growth rate of the cultured calli was reduced by the irradiation and became brown significantly 2 weeks after the $^{14}$ N and $^{20}$ Ne ion beam irradiation over 50 Gy. The increased intensity of the heavy-ion ($^{14}$ N, $^{20}$ Ne) beam irradiation resulted in the delay of seed germination and the inhibition of the early growth both in water-treated and non-treated seeds before the irradiation. In addition, the heavy-ion beam irradiation to the imbibed seeds inhibited seed germination more than that to the non-imbibed seeds. The screening approach of non-imbibed seeds with heavy-ion beam irradiation using in vitro culture system was more useful than the filter-paper germination method in investigating the characteristics of heavy-ion beam-irradiated seed population and the screening of morphological variants at the early stage of the plant growth.