• Weed & Turfgrass Science
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• v.4 no.1
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• pp.58-64
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• 2015

The black cutworm, Agrotis ipsilon (Hufnagel) is a major insect pest of economic crops including turfgrasses on golf courses. The entomopathogenic nematode, Steinernema carpocapsae GSN1 strain (ScG), a Korean isolate, is an effective biological control agent for soil dwelling and greenhouse insect pests in Korea. In addition, ScG is commercially produced in Korea. We conducted laboratory, greenhouse, and field trials to evaluate efficacy of ScG against black cutworms in turfgrasses. A rate of 63 infective juveniles (Ijs) per larva killed >90% of $3^{rd}$ instars feeding in cups of artificial diet within 3 days. In greenhouse trials against cutworms feeding in pots of turfgrass, efficacy of ScG was higher against $4^{th}$ instars than against $2^{nd}$ instars (90.0 vs 81.2% mortality, respectively, at $2,000Ijs\;pot^{-1}$) in perennial ryegrass, and higher against $3^{rd}$ instars in creeping bentgrass, Agrostis palustris than in zoysiagrass, Zoysia japonica (96.7 vs 52.5% mortality at $100,000Ijs\;m^{-2}$) in pot. The corrected mortality of $4^{th}$ instar was 79.9% at the rate of $100,000Ijs\;m^{-2}$ in the creeping bentgrass in the field. So ScG could be used as biological control agent against black cutworm in turfgrass of golf courses.

• Weed & Turfgrass Science
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• v.4 no.4
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• pp.368-375
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• 2015

Earthworm cast occurred in surface of turfgrass in golf courses which affect turfgrass maintenance and golf play. In this study several survey of seasonal fluctuation of earthworm cast in different golf courses (Anseong, Gapyeong, Gunpo and Yongin in Gyeonggi province, and Geumjeong in Busan) was done. A number of earthworm, soil temperature and moisture of detection site of earthworm cast in each golf course were also done. Cast occurred in different golf courses are found mostly from April to November on turf surface and the cast number varied in different month as well as in golf courses. In the same golf courses, a number of detected cast was difference from individual sites. A number of cast and earthworm was correlated. Also, in higher soil moisture showed the higher cast density in different golf courses. Soil temperature and moisture of detecting cast ranging from $2.1^{\circ}C$ to $33.1^{\circ}C$ and 4.9 to 44.1%, respectively. In case of cast, soil temperature level lies in between $10-15^{\circ}C$ where the highest soil moisture was 25%.

• Weed & Turfgrass Science
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• v.2 no.2
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• pp.184-190
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• 2013

It is important for genetic resources to collect and identify in native medium-leaf type zoysiagrasses species distributed in Korea. This study was conducted to investigate morphological variation and characteristics of native medium-leaf type zoysiagrasses from coastal, island and inland regions in Korea. Among them, 75 collected lines was confirmed to have various morphological variations, accessions were classified into 2 main based group coastal and inland regions by morphological characteristics and site environment. Group I included Z. sinica type, this group showed 3.7 mm in leaf width, 29 in number of seed per spikelet and 5.0 mm in seed length. Group II included Z. japonica type, this group showed 4.4 mm in leaf width, 42 in number of seed per spikelet and 3.5 mm in seed length. There is a need for additional research on growth characteristics and the molecular level for the introgressive hybridization between species which confirmed that cross-pollination is possible due to protogyny. The individuals showing variations should be preserved as valuable genetic resources for the expansion of variations in zoysiagrasses, and the results of this investigation on the genetic resources collected will be highly valuable in breeding high quality turfgrass.

• Asian Journal of Turfgrass Science
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• v.20 no.2
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• pp.175-190
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• 2006

The term mycoherbicide started in 1970, but its interest heightened due to increase costs of chemical herbicides. A classical biocontrol agent is expected to become a permanent part of its new environment and do no harm to it. Contemporary biological control agent(BCA) must be produced by artificial culture and could be applied like chemical herbicides over weeds. BCA is different from the classical approach in that it released through natural spread. To date 26 species of fungi are used as classical BCA against 26 species of weeds in seven countries. There are a number of examples of pathogens attacking non-target plants. But through risk assessments which include understanding the taxonomy, biology and ecology, the target and non-target species, it will be safe to introduce of exotic pathogens to control weeds. But pathogens have not been successfully used in practice. Many mycoherbicides show potential in laboratories, but are ineffective in the field and not consistent from year to year or field to field. There is also a lack of understanding humidity, dew formation and temperature and their effects on suppression of weeds by plant pathogens. Potential pathogen must be selected as a BCA. Previous studies suggest that these pathogens must (1) produce abundant and durable inoculum in artifical culture, (2) be genetically stable and weed specific and (3) kill weeds in control. A granular preparation of mycoherbicide into sodium alginate is lighter than liquids and less bulky than organic matter. Gel forms have also been used.

• Asian Journal of Turfgrass Science
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• v.25 no.2
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• pp.237-242
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• 2011

The 2011 Japanese Society of Turfgrass Science was divided in oral presentation, sectional meeting and small symposium, and the total 55 subject was announced. The oral presentation was reported physiological ecology of turf, disease and weed; field management; pesticidal activity and spectrum of new turf pesticides. Above all, there was presentation that investigated control method of necrotic ring spot of new turf disease and Cyperus brevifolius, annual bluegrass and mouse-ear chickweed. In addition, the control effect of new registration fungicide (Furametpyr) and herbicides (S-metolachlor, Flucetosulfuron and Foramsulfuron) were announced. There was various information interchange through 4 kinds of subjects of a golf course, ground turf, a urban park greens and ground cover plants greening by the sectional meeting, and the genetic resource of turfgrass discussed by small symposium. Specially, park greens sectional meeting was announced about the radioactive material contaminated on mechanism and effectively removal method of the radioactivity contaminant from public park, school ground and domestic lawn.

• Korean Journal of Environmental Biology
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• v.38 no.3
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• pp.450-460
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• 2020

The occurrence of exotic weeds and their influx into farmlands due to climate change poses many problems. Therefore, it is necessary to generate a prediction model for the occurrence pattern of these exotic weeds based on scientific evidence and devise prevention measures. The photosynthetic apparatus is known as the most temperature-sensitive component of a plant cell and its initial response to temperature stress is to inhibit the activation of photosystem II. This study investigated the potential of OJIP transients in assessing temperature stress in exotic weeds. The four exotic weeds currently flowing into Korean farmlands include Amaranthus spinosus, Conyza bonariensis, Crassocephalum crepidioides, and Amaranthus viridis. These weeds were treated at 5℃, 10℃, 15℃, 20℃, 25℃, 30℃, 35℃, and 40℃ and the OJIP curves and JIP parameters were measured and analyzed. The results showed that heat and chilling stress affected the photosystem II(PSII) electron transport of A. spinosus, whereas C. crepidioides and A. viridis were more affected by high-temperature stress than by low-temperature stress. Lastly, C. bonariensis showed resistance to both high and low-temperature stress. The results of this study suggest that OJIP transients and JIP parameters can be used to analyze damage to the photosynthetic apparatus by temperature stress and that they can serve as sensitive indicators for the occurrence pattern of exotic weeds.

• Korean journal of applied entomology
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• v.44 no.1 s.138
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• pp.73-90
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• 2005

Although the history of IPM can be traced back to the late 19th century, when ecology was identified as the foundation for scientific plant protection, it has been more than thirty years since first enunciation. Since than, the concept of IPM has evolved in multiple paths not only in entomology but in plant pathology and in weed science, and the philosophy has become a firm foundation to the science of plant protection. The IPM concept has gained wide general acceptance, however, because of the many-facet aspects, there has been some controversy and/or misunderstanding by the students and practitioners. In this paper, I was tried to review the concepts of IPM and to resolve the contradiction between the philosophy and practical techniques. On this line, the historical background and the concept of economic injury level, which is the foundation of the concepts, are reviewed and discussed the sampling techniques and the population dynamics of single pest, which were basic to the rational and effective application of the management techniques. IPM is not a science per se but it is a technique and it should be applicable to the real conditions. For this purpose, the information on the pests should be transferred to the producers as fast as possible. From such, some of my own opinion is presented in relation to current systems of the pest occurrence forecasting.

• Journal of the Korean Institute of Landscape Architecture
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• v.18 no.4
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• pp.45-71
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• 1991

The landscape systems in Korean island settlements can be recognized as results of ingabitants' ecological adptation to the isolated environment with the limited natural resources. Both the fishery dominant industry in island society and ecological nature of its environments seem to have influenced on inhabitants' environmental cognition as well as the physical landscape of island villages such as its location, spatial pattern in each village, housing form and so on. This study was done mainly by both refering to the related documents and direct observations in case study areas, and results of the study can be summarized as follows. 1. In general, the landscape of an individual island seems to take more innate characteristics of island's own, corresponding to the degree of isolation from mainland. That is, while the landscape of island in neighboring waters takes both inland-like and island-innate landscape character at the same time, the one in the open sea far from land takes more innate landscape character of all island's own in the aspects of village location, land use and housing density etc. 2. The convex landform of most islands brings about more centrifugal village allocation than centripetal allocation in most inland villages. And thus most villages in each island face extremely diverse directions different from the south facing preference in most inland rural villages. 3. Most island villages tend to be located along the ecologically transitional strip between land and sea, so called 'line of life', rather than between hilly slope and flat land as being in most inland village locations. So they are located with marine ecology bounded fishing ground ahead and land ecology bounded agricultural site at the back of them. 4. The settlement pattern of the island fishing villages shows more compact spatial structure than that of inland agricultural villages, due to the absolute limits of usable land resources and the adaptation to the marine environment with severe sea winds and waves or for the easy accessability to the fishing grounds. And also the managerial patterns of public owned sea weed catching ground, which take each family as the unit of usership rather than an individual, seem to make the villagescape more compact and the size of Individual residence smaller than that of inland agricultural village. 5. The folk shrine('Dand') systems, in persrective of villagescape, represent innate environmental cognition of island inhabitants above all other cultural landscape elements in the island. Usually the kinds and the meanings of island's communal shrine and its allocative patternsin island villagescape are composed of set with binary opposition, for example 'Upper shrine(representing 'earth', 'mountain' or 'fire')' and 'Lower Shrine(representing 'sea', 'dragon' or 'water') are those. They are usually located at contrary positions in villagescape each other. That is, they are located at 'the virtical center or visual terminus(Upper shrine at hillside behind the village)' and 'the border or entrance(Lower Shrine at seashore in front of the village)'. Each of these shirines' divinity coincides with each subsystem of island's natural eco-system(earth sphere vs marine sphere) and they also contribute to ecological conservation, bonded with the 'Sacred Forest(usually with another function of windbreak)' or 'Sacred Natural Fountain' nearby them, which are representatives of island's natural resources.

• Korean Journal of Environment and Ecology
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• v.29 no.6
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• pp.907-916
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• 2015

The purpose of this study was to identify characteristics of vegetation structure, vegetation succession, and species diversity of artificially planted Chamaecyparis obtusa (CO) stands. The study was carried out by performing vegetation survey for eight CO stands located in Jeollanam-do Province, Korea. Analysis on vegetation classification and ordinations of the stands was conducted using the data from the vegetation survey, and as a result, the stands were classified into five types of communities. Community I showed a considerably lower index of species diversity when compared to other communities because the canopy of the dominant CO was so highly dense that the low-height vegetation was not able to develop or the low-height vegetation almost disappeared due to elimination of weed trees. Meanwhile, the Community II - IV had relatively higher indices of species diversity because various native tree species mixed with the low-height vegetation and competed with each other in the understory and shrub layers to some degree of stability or in their early stage of vegetation development. Community V, lastly, showed higher use intensity as a recreational forest, thus developing simpler vegetation structure on account of artificial intervention. There was positive correlation between photosynthetically active radiation entering the forest floor, number of observed species and index of species diversity. Such characteristics of vegetation structure in CO stands are closely associated with forest management and prescription for planting reforestation, thinning, and brush cutting in the past. There was a slight difference in vegetation structure and species diversity by communities, based on rotation time of the vegetational succession, process of disturbance frequency and disturbance, development, and maturity by planting CO stands. However, when compared to natural forests, the CO stands showed simpler vegetation structure. Because artificial forests are vulnerable in ecosystem service with lower species diversity, a drive for ecological management is needed for such forests to change into healthy ecosystems that can display functions of public benefit.

• Korean Journal of Weed Science
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• v.13 no.2
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• pp.96-103
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• 1993

The experiments on the ecological characteristics of the suspensible green algae and the algae causing soil-flakes and shier chemical control were conducted in 1992. The unicellular green algae which were dominated by Chlamydomonas sp. largely occurred when phosphorus was applied, but which were reduced by nitrogen application. The filamentous green algae which were dominated by Klebsormidium sp. largely occurred when phosphorus was applied, and which much more increased when nitrogen or potassium was combined with phosphorus. The suspensible green algae which were dominated by Klebsormidium sp. were controlled by 60-70% when simazine 10g ai/10a and propanil 105g ai/10a were applied. The dark blue soil-flakes largely occurred at nitrogen application, and which much more increased when nitrogen was combined with phosphorus. The dark brown soil-flakes largely occurred at phosphorus application, but no more increased even if nitrogen or potassium was combined with phosphorus. The dark blue soil-flakes which were dominated by Oscillatoria sp. much more increased at the temperature conditions of $18^{\circ}C$ compared with $24^{\circ}C$ and $29^{\circ}C$. The applications of bensulfuron/mefenacet/dymron, piperophos/dimethametryn and bensulfuron/dimepiperate controlled 70-90% of the dark blue soil-flakes.