• KOREAN JOURNAL OF CROP SCIENCE
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• v.4 no.1
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• pp.81-91
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• 1968

To investigate the effects of foliage clipping time, degree, and nitrogen top-dressing after clipping on the growth and the agronomic characteristics, rice plants grown under ordinary cultural practices were clipped at the maximum tiller stage, 10 days prior to, and after that stage, respectively, with varying clipping, height, as 0, 1/3, 1/2, and 2/3 of plant height. And nitrogen was top-dressed at the rate of 0, 2, 4, 6 kg per 10 are immediately after clipping. The variety used was ＂Jinheung＂. The results obtained are outlined as follows: 1. Effect of clipping on the growth of rice plant: The subsequent growth was quite rapid during 10 days after clipping, and resulted, on the whole, in nearly complete recovery of defoliation by 20 days after clipping. a) Generally, the later the clipping time, the more growth accelerated. Rice plants clipped before the differentiation of ear primordia nearly recovered the damage, and in certain cases exceeded non-clipped plants in height. But the height of the rice plant clipped after the differentiation of ear primordia was somewhat smaller than that of non-clipped. b) Growth rate was rather rapid in the case of severe cutting, and the height of slightly clipped plants was taller than that of non-clipped plants. However, rice plants clipped to the extent of 2/3 of plant height did not fully recover the damage of defoliation compared to non-clipped plants. c) Nitrogen dressing was effective to rapid recovery of defoliation, the effect increasing with the increasing amount of application. d) Ear-heading was delayed in clipped plots, and this tendency was more apparent with later clipping time, more severe clipping, and increased amounts of nitrogen application after cutting. The range was 6 days at maximum. 2. Effect of defoliation on the yield and its components of rice plants: The yield response to clipping varied somewhat with its time, degree, and nitrogen application after cutting: yield increase of about 10% and decreasement of about 25% at maximum compared to the control plot. Grain yield of most plots was decreased. a) Clipping before the differentiation of ear primordia did not much affect the agronomic characteristics of rice plants. However, clipping after that growth stage decreased culm length, number of panicles, number of spikelets per panicle, and maturing rate of grain to some extent. Consequently this treatment resulted in decrease of about 10% in grain and straw production in spite of increase in panicle length and effective tillering rate. b) Slight, clipping decreased number of spikelets per panicle a little, and the yield of grain and straw by 4-5%, although effective tillering rate was somewhat increased. With severe clipping, panicle kngth, number of panicles, and number of spikelets per panicle decreased more, and the yield of grain and straw decreased about 10%. c) Nitrogen dressing after clipping at the rate of 2 kg per 10 are was effective in increasing grain yield. Nitrogen application over the rate of 4 kg per 10 are increased culm length, number of spikelets per panicle, and straw production, but this decreased the maturing rate, and the 1, 000-grains weight to some extent and resulted in decrease of grain yield.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.1
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• pp.53-57
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• 2013

A severe defoliation by typhoon in early autumn reduces fruit quality for the current season and reserve accumulations for the next season. This study was conducted to determine the effects of foliar applications during the autumn on alleviating the damages after defoliation. Leaves of 2-year-old 'Fuyu' trees, grown in 50-L pots under a rain-shelter, were 75%-defoliated on September 9. In mid-September and early October, trees were treated either with eight foliar applications of urea or with four alternating applications of urea and $KH_2PO_4$ (urea + KP application), all at 0.5% (w/v). Trees untreated after the defoliation served as the control. The urea applications slightly increased N and P concentrations of the leaves collected on November 6, while urea + KP applications significantly increased P and K concentrations. Foliar applications did not affect fruit growth, but tended to decrease skin coloration. Fruit soluble solids increased by 1.5 and $1.0^{\circ}Brix$ for urea and urea + KP applications, respectively. There was a significant increase in dry weight of fine root for the foliar application treatments but not in those of aerial woods and larger roots. With the foliar applications, N concentration tended to increase in the permanent organs but not P and K, whereas soluble sugars and starch notably increased in shoot, trunk, or fine root regardless of the different applications. Results indicated that the foliar applications could partially help to restore fruit quality and carbohydrate accumulations in the defoliated trees.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.121.1-121
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• 2003

Dispersal of Xanthomonas axonopodis pv. citri, causing citrus bacterial canker disease on Unshiu orange was investigated at previously infested plots at Seogwipo in Jeju island of Korea. The bacterial pathogen overwintered in lesions started to multiply at tate May, and disease firstly observed one month after detection of phage from lesions. The disease gradually increased, however, it dispersed non-directionally to nearby plants from inoculum sources. Diseased plants were aggregated to form a cluster throughout the experiment. Population dynamics of phage on symtomless leaf surface and the disease severity were compared in the nursery, Increase of phage population on symptomless leaf surface preceded one month to that of the disease severity Population of phage increased constantly from late July to October, however, the disease severity decreased from late August to late October. It was assumed that the decrease of disease severity might be due to disease-induced defoliation.

• Journal of the Korean Institute of Landscape Architecture
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• v.25 no.3
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• pp.177-185
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• 1997

Hibiscus syriacus were surveyed to study the growing temperature, relative humidity and growing responses shown at different elevations of Kangwon Province, and results of the assessment are summarized as follows 1. Growing responses as represented by leaf length, leaf width, shoot length, number of flowers and flowering duration, were decreased as the elevation increased, while the degree of defoliation was increased. 2. The important factor determining the growing responses to the elevation was the maximum and minimum temperatures, particularly those of July, August, and September. 3. The aphid occurrence on Hibiscus syriacus decreased as the elevation increased. Leading factor determining the population was relative humidity which increased as the elevation increased.

• 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.

• The Plant Pathology Journal
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• v.24 no.1
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• pp.97-100
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• 2008

Leaf blight symptoms and abnormal defoliation were found on Stachys riederi var. japonica, a medicinal plant, grown at Hongcheon, Gangwon province, Korea in 2007. A foliar nematode, Aphelenchoides fragariae was isolated from infected leaf tissues. The symptoms observed on host plant were leaf blotching, discoloration and browning of tissues, tan-colored interveinal necrotic lesions and large dead patches of necrotic tissues. This is the first report of A. fragariae occurring on S. riederi var. japonica.

• Journal of Ginseng Research
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• v.15 no.1
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• pp.21-30
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• 1991

This study was conducted to know the elects of light intensity of polyethylene net shading on the growth status, photosynthesis and root yield of ginseng plants. Polyethylene net shading of loft transmittance was the best one among light intensities of polyethylene net used in view of photosynthesis and decreasing of early leaf defoliation. According to increase of light intensity under the shading chlorophyll contents of ginseng leaves were decreased. As it was increased over 2 mg/g Photosynthesis and total saponin of leaves showed on the decrease remarkably. The rate of alternaria blight of ginseng plants showed the positive correlation between light intensity and leaking rate. The shading of 10% transmittance in root yield was increased by 40% in 6-year-old ginseng plant as compared with common straw shading, due to decreased missing plant and increased root weight.

• Korean Journal Plant Pathology
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• v.14 no.6
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• pp.732-734
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• 1998

Leaf spot of Amelanchier asiatica was observed in Korea.. The major symptoms of the disease were small necrotic spots and severe early defoliation. On the basis of morphological characteristics of the fungus observed from naturally infected leaves, the causal organism was identified as Entomosporium mespili (DC. : Duby) Sacc. The conidial suspension prepared from sporulating lesions was sprayed on healthy leaves with or without wounding to prove pathogenicity of the fungus. Small spots were noticed tow days after inoculation, and acervuli containing numerous conidia were observed 7 and 10 days after inoculation from wounded and unwounded leaves, respectively. This is the first record of the disease on A. asiatica in Korea.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.5
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• pp.459-480
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• 1991

Physilogical disorders of P. ginseng occurred in farmer's field were reviewed in relation to symptom. In root, red skin, rough skin, rust, root rot complex, round root, fine root stripe, freezing injury, cracking, sleeping and uneven emergence were frequently appeared. In leaf and stem, yellowing, early defoliation, leaf bum, Papery leaf, white freezing injury, wind injury, stem cracking were the main troubles. Red skin of root and leaf yellowing gave the greatest negative impact on ginseng production. Some cases of damage by pesticides, excess boron and industrial pollutants were reported. Physiological disorders related to quality factors, such as inside cavity, inside white sponge-like ect. after processing were discussed.

• Research in Plant Disease
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• v.28 no.2
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• pp.57-60
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• 2022

Leaves of Chionanthus retusus were found to be damaged by leaf spot disease associated with a fungus in Iksan, Korea. Leaf spots were angular to irregular, vein-limited, scattered, 1-8 mm diameter, brownish-gray to dark brown when dry, with heavy fructification. The pathogen causes premature defoliation of C. retusus plant and was identified as Pseudocercospora chionanthi-retusi based on morphological and molecular-phylogenetic analyses. The phylogenetic tree was constructed using multi-locus DNA sequence data of partial actin (actA), partial translation elongation factor 1-alfa (tef1), partial DNA-directed RNA polymerase II second largest subunit (rpb2) genes, and internal transcribed spacer regions. Current study provides detail morphological description of P. chionanthi-retusi on C. retusus in Korea, with supports of phylogenetic analysis and pathogenicity test.