• BMB Reports
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• v.33 no.5
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• pp.385-390
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• 2000

Overwintering plants should survive the various biotic and abiotic stresses that occur during winter. Previous studies indicated that active oxygen species are involved in freezing, dehydration, anoxia and pathogen infections. As the importance of the events that occur in the intercellular compartment became apparent in disease resistance, we examined the nature of intercellular antioxidant enzymes in order to access their possible involvement in the winter hardiness of barley. The levels of intercellular peroxidase, catalase, and SOD activities on the unit protein basis were 394, 18, and 9% of those of cellular activities, respectively. Major intercellular peroxidase isoforms consisted of four neutrals and four basic forms; whereas major cellular isoforms were two basic forms. Out of the two major catalase isoforms a higher molecular weight form was predominantly abundant in both cellular and intercellular compartments. Among the five major cellular SOD isoforms, three were also present in the intercellular compartment. The presence of substantial amounts of intercellular antioxidant enzymes in overwintering barley leaves may suggest the involvement of these enzymes in the tolerance mechanism to the various stresses that occur during winter.

• Korean journal of applied entomology
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• v.10 no.1
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• pp.39-41
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• 1971

Apple bitter rot caused by Glomerella cingulata has been known to occur annually on the fruits of previously infected twigs and the trunks. This study was carried out to ensure whether the pathogen overwinters in the form of perithecium or not. Since the acervuli of the pathogen were formed in inoculated apple trees, it would be possible that the pathogen could overwinter on the twigs, Ascigerous stage was found both under the cuticle of the infected trunk and in outer layers of rotted fruits. Therefore, it could be concluded that the pathogen overwintered in the form of perithecium is a primary inoculum in next year. Ascigerous stage of the appfe bitter rot organism was observed for the first time in Korea.

• Korean journal of applied entomology
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• v.30 no.3
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• pp.169-173
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• 1991

These studies were conducted to investigate overwintering forms and adult population fluctuation in field condition, and life cycle in field-cage condition of diamondback moth, Plutella xylostella (L.). Plutella xylostella overwintered as all the stages of eggs, larvae, pupae and adults in southern region of Korea. The occurrence which adult moths were attracted by light trap at 5-day intervals, reached their peaks in May, mid-June to mid-July, and late September to early November, and fell in late July to mid-September. Under field-cage condition, they occurred 10-11 generations a year and the period of adult emergence from egg was 11-18 days in July and August, 19-23 days in June and September, 28-34 days in April, May and October, and about 50-100 days in other months. And the longevities of adults were 4-11 days in summer, 7-17 days in spring and fall. A number of eggs laid by individual female ranged from 50 to 240. The females laid more eggs in spring and fall than they did in summer. The period of developmental stages under field-cage conditions was 2-3 days for eggs, 7-8 days for larvae and 4-6 days for pupae in July and August; 4-5 days for eggs, 3-12 days for larvae and 6-8 days for pupae in June and September; 6-18 days for eggs, 13-20 days for larvae and 8-14 days for pupae in March, April, May and October; and 12-40 days for eggs, 50-100 days for larvae, and about 20 days for pupae in winter.

• Korean Journal of Agricultural and Forest Meteorology
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• v.25 no.1
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• pp.37-47
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• 2023

The black cutworm, Agrotis ipsilon (Hufnagel), is an important crop pest worldwide that feeds more than 80 plant species including cabbage, potato, maize, wheat and bean, and this moth is a typical pest attacking underground parts of crops. It has been known in farm booklets that the larvae of A. ipsilon overwinter in the soil in Korea, but no definitive data exist yet. This study was conducted to evaluate that the specific appearance time of A. ipsilon observed actually in the field could be explained when we assumed that this pest overwinters in a form of larvae or pupae. Degree day-based phenology models were applied for tracking forward or backward to find the predicted developmental stage which developed at a specific stage found in the field. As a result of the analysis, it was confirmed that an initial population could be established in a group that does not overwinter as larvae or pupae in Korea. In other words, the appearance of adults in early March to April could not be explained by the presence of domestic overwintering populations. Populations that overwinter as larvae or pupae in Korea were able to emerge as adults in June to July at the earliest. Therefore, the group of adults appearing in early spring is highly likely to be a population that migrated from outside Korea. Taken together, it was estimated that the colony of A. ipsilon in Korea would be formed by a mixture of a migrant population through long-distance migration and a overwintering population.

• Journal of The Korean Society of Grassland and Forage Science
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• v.14 no.4
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• pp.324-330
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• 1994

The objective of this study is to obtain the basic data for investigating the potentiality of continuous utili~ation (first cutting in the late fall and regrowth yield in next spring) of forage rape seeded in fall. Fresh yield and the content of nitrogenous compound in leaves and roots were measured during a growth period. Fresh yield accumulation was very low between the late fall(470kg/10a) and the early regrowth period( 1.070kg /IOa). Total nitrogen content in leaves until the wintering period was decreased from 4.71% to 3.70%. while that in roots slightly increased during this period. The highest content(4.84%) in roots was observed in the early regrowth period, and then rapidly decreased as growth advanced. Protein-N was the largest pool of nitrogenous compound in leaves and roots through entire growth period, Its content in leaves decreased until the wintering period (Feb. 4), and then increased until the bolting stage(Apr. 10). Protein-N in roots highly accumulated from the late fall(11.1mg/gDM) to the early regrowth period(l6.9mg/gDM), and then decreased until the early tlowering stage. The content of amino acid-N in leaves showed a little change with a range from 5.7 to 8.5mgIgDM during entire growth period, while that in roots rapidly decreased from early regrowth period. The content of $NO_3$-N decreased from 7.0 to 4.3mglgDM in leaves, while increased from 0.9 to 2.3mg/gDM in roots from the late fall to the wintering period. 7he content of $NH_4$-N was lower and less varillble than other nitrogen compound during entire growth period. The results clearly showed that protein-N was the main storage form and highly accumulated in roots of overwintering forage rape.

• Journal of The Korean Society of Grassland and Forage Science
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• v.21 no.4
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• pp.259-264
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• 2001

To investigate the physiological responses to naturally occurring winter freezing stress in creeping bentgrass, changes in carbohydrates were monitored during winter period. Turf quality and leaf growth was nearly parallel with temperature fluctuation. The concentration of glucose, fructose and sucrose in both shoot and root gradually increased from November to January, and then sharply decreased until April. Sucrose was the largest pool of soluble sugars. Fructan also slightly accumulated in both shoot and roots from November to February. Fructan hydrolysis in both organs was found to be much active between February to April. Shoot contained largely higher carbohydrate content in all compounds examined than roots did. Fructan was found to be a main carbohydrate storage form, showing the highest concentration (176.7 and 126.7 mg g-' DW for shoot and root in February). The depolymerization of fructan from February coincided with the high declines in mono- and disaccharide. These results suggest that the accumulation of non-structural carbohydrate until January could be associated with freezing tolerance, and the active decrease from February with shoot regrowth.

• Journal of Environmental Science International
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• v.25 no.12
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• pp.1633-1641
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• 2016

Leptalina unicolor is a hesperiid butterfly with a restricted distribution in Korea, Japan, China, and Russia. Recently, the number of individuals is rapidly decreased in their natural habitat. This skipper has been classified as an endangered species in the 'Red Data Book', and according to an IUCN report, is under threat of extinction. Therefore, the conservation and restoration of this species both locally and globally are urgently needed. A population of L. unicolor was found in an unknown habitat in Jaeyaksan, Miryang, Gyeongsangnam-do, Korea in 2011, and these individuals were used in the present study. Here, the life cycle, characteristics of each instar larva and breeding information were determined by breeding L. unicolor in the laboratory from 2012 to 2015. The results indicated that L. unicolor occurs twice a year and over-winter as a fifth instar larva. A spring-form female individual laid $17.25{\pm}5.52eggs$, and summer form laid $29.00{\pm}5.86eggs$; it takes $53.79{\pm}0.73days$ for L. unicolor to develop from eggs to adults. After spawning, the eggs developed in $6.16{\pm}0.18days$, and larvae developed in $33.71{\pm}0.58days$; the pre-pupal stage to emergence required $14.22{\pm}0.31days$. Based on these results, we presented effective breeding information for the restoration and proliferation of the species. Several candidate plants species have been reported in the literature as a food source for L. unicolor, but we found that the preferred diet this butterfly was Miscanthus sinensis. The larvae could move easily when their preferred diet was planted in ${\geq}80%$ the cage floor area Year-round breeding was achieved by placing overwintering individuals in low temperatures in autumn. To our knowledge, this is the first study to the biology of L. unicolor in Korea, and the results of this study could be used as preliminary information for the conservation and restoration of this species in its natural habitat.

• Korean journal of applied entomology
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• v.32 no.1
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• pp.83-89
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• 1993

This study investigated seasonal occurrence, host preference and developmental characteristics of E. lagerstroemiae was most likely to have two generations a year with first occurrence of adults form late April to late may and second from late August to late October including 2 peaks in early May and late August, respectively. Overwintering stages were mostly eggs and larvae and its composition rate was 57.1% of eggs and 42.9% of larvae. Host plats investigated were 7 species 7 families and most preferred species were Lagerstroemia japonica and Diospyros kaki. As morphological characteristics of E. lagerstroemiae, sized of length/sidth were 0.29/0.16 mm for the egg. 0.41/0.16 mm for the first instar larva, 0.96/0.47 mm for the male adult. Number of eggs deposited per female adult was 221.9 individuals. Hatching rate at various temperatures was above 90% at below $30^{\circ}C$. Egg periods were also short\ened with increase of temperatures at below $30^{\circ}C$ but decreased to 56.3% at $35^{\circ}C$. Egg periods were also shortened with increase of temperatures at below $30^{\circ}C$. Hatching rate was not affected by photoperiods but egg periods were shortened with increase of day length.

• Research in Plant Disease
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• v.10 no.4
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• pp.209-216
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• 2004

The circular leaf spot of persimmon is occurred almost every place where persimmon is cultivated, especially the disease outbreak severely in southern part of Korea. The disease reveals unusually long incubation period after pathogen invade into leaf tissue and no practical control measure is available once the symptom has appeared. Most of the farmers just follow the suggested spray schedules calculated on the basis of weather condition of ordinary years. Therefore the damages due to circular leaf spot greatly differ year after year. In this article, we tried to describe and summarized the investigation on the circular leaf spot pathogen, Mycosphaerella nawae, related to disease outbreak such as overwintering of pathogen, inoculum formation and spread, incubation period after infection, and secondary inoculum. With the summary of these results, we suggest the disease cycle of circular leaf spot of persimmon. The pathogen overwinters in diseased leaves as mycelial form or pseudoperithecial premodium. The pseudoperitheria become matured in spring as the temperature raise and forms asci and ascospores. The maturation of pseudoperithecia are closely related to the temperatures during March and early April. The ascospores completely mature in early May and the ascospores released when the pseudoperithecia absorbed enough moisture after rainfall. The release of ascospores are diverse greatly with the variation of maturity of pseudoperithecia. Generally the spore start to release from middle of May to early of July. Duration of ascospore release is depend on the weather condition of particular year, especially amount and number of precipitation. The ascospores produced from pseudoperithecia is known to the only inoculum for circular leaf spot disease. But according to the results obtained from our investigations, the conidia formed on the lesions which incited by natural infection. This conidia are infectious to persimmon leaves and formed identical symptom as natural infection. The time of producing secondary inoculum of circular leaf spot of persimmon is considered too late to develop new disease. Generally the importance of secondary inoculum is low but the conidia produced in early September are competent to develop new disease and new infection also significantly affect to harvest of persimmon. The importance of circular leaf spot disease is recognized well to farmers. The approaches to control of the disease should be initiated on the basis of the knowledges of inoculum dynamics and ecology of disease development. The forecasting system for circular leaf spot is need to be developed.

• Korean journal of applied entomology
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• v.39 no.2
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• pp.73-82
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• 2000

Two Psyllidae species of Cacopsylla pyricola (Foerster) and C. pyrisuga (Foerster)damaging pear trees have been reported in Korea. However, their ecological characteristics and damagepatterns have not been evaluated yet. To establish basic control measures of C. pyricola, field phenology,overwintering ecology, seasonal fluctuation and temperature-dependent development of C. pyricola wereexamined. C. pyricola overwintered under the bark scale of pear trees as winter form adults and theymoved to fruiting twigs from mid-February. Honeydew produced by C. pyricola nymphs and adults asthey feed caused serious black sooty mold on leaves and fruits. The seasonal occurrence of C. pyricolawas different every year. In 1993, characterized by cold temperature and heavy precipitation, C. pyricolapopulation was maintained highly during growing season. However, the population was decreased rapidlyfrom early July in 1994, year of hot and dry weather condition. In 1995, year of average temperature, thedensity of C. pyricola population was decreased during hot months of July and August, and rebuilt up inSeptember and October. The development periods of C. pyricola eggs were 13.33 days at 15"C, 9.32 daysat 20$^{\circ}$C, 7.82 days at 25"C, 6.60 days at 30$^{\circ}$C, and 7.75 days at 35$^{\circ}$C. The development periods ofnymphs were 33.75 days at 15OC, 23.77 days at 20$^{\circ}$C, 15.21 days at 25"C, and 17.40 days at 30$^{\circ}$C. Theirdevelopment periods and mortalities were increased in higher temperatures. The parameters of nonlineardevelopment model, Weibull and linear development models of Cacopsylla pyricola were estimated.models of Cacopsylla pyricola were estimated.