• Weed & Turfgrass Science
• /
• v.2 no.3
• /
• pp.221-229
• /
• 2013

This paper reviews current status of weed control practices in herbicide-resistant crops to examine weed management strategies in cope with cropping herbicide-resistant crops in the near future. Herbicide-resistant crops were rapidly adopted weed management technologies due to broad-spectrum weed control without crop injury. Transgenic glyphosate-resistant cultivars in soybean, corn, canola, and cotton were adopted to manage weeds at lower cost in a simplified weed management system. Dual stack crops with glyphosate and glufosinate resistance were developed to control glyphosate resistant weeds in corn, soybean and cotton. New multiple herbicide-resistant crops with resistance to glyphosate and glufosinate, acetolactate synthase (ALS) inhibitors, synthetic auxin herbicides, 4-hydroxyphenyl pyruvate dioxygenase (HPPD) inhibitors or acetyl Coenzyme A carboxylase (ACCase) inhibitors will expended the utility of existing herbicide technologies to manage the evolution of resistant weeds. However, herbicide resistant crops alone cannot solve weed problems and thus studies on diverse weed managements using an array of alternating herbicides of mode of action, mechanical, and cultural practices are needed for integrated weed management systems in the future.

• Korean Journal of Weed Science
• /
• v.13 no.4
• /
• pp.195-202
• /
• 1993

The benefits of pesticides in improving the food quantity and quality requirements for an increasing world population are significant, and they can be described in agronomic, economic and social terms. The risks are assessed from the hazards which are likely to occur in practice ; the hazards are defined by the toxicity of the pesticide to non-target organisms at various exposure levels. There are ways of reducing the risks (mainly by reducing exposure in practice) and improving the benefits of pesticides ; these are known as risk management and benefit management respectively. The overall risk-benefit assessment is facilitated if each component can be expressed in financial terms, but it must be made nationally or locally on a sound technical basis against the prevailing agronomic, socio-economic and political circumstances. Paraquat is used to illustrate the risk-benefit assessment process in general terms, and the conclusion is that the benefits greatly outweigh the risks. It is important to keep the risks of pesticides in perspective with those associated with other naturally occurring chemicals in our diet and with other everyday aspects of life. In an overall context, the pesticide risk is small.

• Asian Journal of Turfgrass Science
• /
• v.22 no.1
• /
• pp.65-74
• /
• 2008

Traffic management is becoming an important issue in turfgrass practise on golf course. The objective of this study was to investigate the combined impact of different traffic times and types of fertilization. Traffic treatment was applied in morning (AM), noon, and afternoon (PM). Fertilizers used include faster-release fertilizer (21-17-17) and slow-release fertilizers (12-6-18, 11-3-22, 20-3-20, 10-3-10). Experiment was conducted from Oct. 1 to Nov. 30, 2005 on a nursery putting green of Incheon Grand Golf Club. The growth and quality of creeping bentgrass (Agrostis polustris cv. 'Seaside II') were evaluated on visual leaf color, leaf texture, shoot density, and root length. The measurement at 20 days after treatment, turfgrass color and leaf texture showed the best result on 10-15-10 + Noon-traffic plot. Turf quality and traffic tolerance were not different at Am and Pm traffic treatment. However, traffic stress in early morning and late evening caused the most severe damage to the turfgrass. Shoot density was the highest in 10-15-10 + Noon-traffic treatment but root length was not different among treatments after 30 day measurement. Among the fertilizers, slow release fertilizer resulted in higher turf quality and traffic tolerance than fast release fertilizer, however, shoot density did not showed a significantly different. For the fast recuperation of turfgrass from traffic injury in the early winter, it is recommended to avoid early morning and late evening traffic such as cup replacement and other maintenance practise. It is also recommended to delay the first tee-up time and ending early for last tee time during cold weather season.

• Weed & Turfgrass Science
• /
• v.5 no.1
• /
• pp.5-9
• /
• 2016

This survey was conducted to identify weed occurrence and to investigate weed management methods in the apple orchard fields in Chungnam province including Daejeon and Sejong from April to June and from September to October, 2015. In this survey, 64 weed species in 27 families including 39 annuals and 25 perennials were identified. Based on the importance values, the most dominant weed species in the first survey was Poa annua (6.51), followed by Veronica didyma (5.36), Plantago asiatica (5.36). In the second survey, Stellaria media (5.73), Digitaria ciliaris (5.36), and Rumex crispus (5.18) were dominant. When the 64 weed species were classified by family, the most abundant weed species belong to Compositae (12 species), followed by Poaceae (7 species), Polygonaceae (6 species), and Cruciferae (6 species). These 31 weed species in the most occurred four families accounted for 48% of total weed occurrence. Based on the questionnaire survey in which weed management methods in the apple orchard were asked, applied mowing + herbicide, mowing + tillage, and mowing + sod-culture was methods commonly conducted in apple orchard fields.

• Weed & Turfgrass Science
• /
• v.5 no.3
• /
• pp.165-169
• /
• 2016

To establish the soil management system for the efficient sod production, survey on the growth of zoysiagrass by different soil managements was conducted in repeated cultivation field with regard to soil physical properties. Soils were subjected to four types of management methods, which include (1) rolling (2) topdressing (3) topdressing + rolling (4) topdressing + tillage + rolling. The topdressing + tillage + rolling treatment significantly ameliorated soil physical properties such as bulk density, porosity and solid phase as compared to rolling and topdressing + rolling treatments, and was not significantly different from the topdressing treatment. Further growth and density of zoysiagrass except for the root dry weight in topdressing + tillage + rolling treatment were significantly higher than that only in rolling treatment. Topdressing + tillage + rolling treatment significantly increased the number of shoot as compared to the other treatments. Therefore, combined topdressing and tillage soil management practice should be conducted for the production of zoysiagrass in repeated cultivation field.

• Weed & Turfgrass Science
• /
• v.5 no.3
• /
• pp.111-125
• /
• 2016

Cordgrass (Spartina spp.) is recognized as a highly invasive plant in estuaries throughout the world because of remarkable versatility and resiliency, significant reproduction, strong adaptability, rapid spreading, and vigorous growth. In this review, therefore, to provide insights on the effective management practices, the previous research works were summarized and discussed. Spartina spp. is a perennial halophyte, warm-season (C4) grass that reproduces both sexually through seeds and asexually by rhizomes. Management strategies for cordgrass have included various physical, biological, and chemical controls. Herbicides are usually the most cost-effective means of control. Currently, glyphosate, imazapyr, fluazifop and haloxyfop have been practically used. To improve the control efficacy, a combination of two more than methods (example, mowing-spraying) is needed to be applied consistently every year for at least 3 to 4 years and to be sprayed with enough dry time (>4-6 hr) at an early growth stage (before flowering). Consistently repeated application of same herbicide have to be avoided to prevent an unexpected emergence of herbicide-resistant lines. On the other hand, Spartina spp. have many positive functions for agricultural and eco-engineering purposes. Thus, we have to give more intensive research for effectively managing advantages and disadvantages of Spartina plantations.

• Asian Journal of Turfgrass Science
• /
• v.15 no.1
• /
• pp.15-20
• /
• 2001

Two types of annual bluegrass have been reported, and those consist of annual type (Poa annua ssp. annua) and perennial type (Poa annua ssp. reptans). As a weed, annual bluegrasses are commonly found in putting greens and fairways in many golf courses. Due to its strong competitiveness such as tremendous seed reproduction rate a year, prostrate growth habit, and no herbicide availability, annual bluegrasses have been considered as one of the most hard-to-control weeds in turf management systems. A growth chamber study was conducted to determine seed dormancy and to understand seed germination characteristics of annual bluegrass (Poa annua ssp. annua). Freshly harvested seeds showed 80 and 55% germination at 30 and $35^{\circ}C$, respectively, indicating that the optimum temperature of annual bluegrass is $30^{\circ}C$. However, the seed germination occurred only under light condition at any given temperature. This result demonstrated that light is prerequisite for the seed germination, and no primary dormancy of annual bluegrass seed exists. Secondary seed dormancy induced by unfavorable temperatures and dark condition was broken through 4 to 6 wk-storage at $4^{\circ}C$ with moisture, and the stored seeds germinated at $20^{\circ}C$ even under the dark. In red and far-red light trial, fresh seeds resulted in 40% germination under red while no seed germination occurred under far-red light condition, indicating that phytochrome Pr and Pfr could be related to annual bluegrass seed germination. When the far-red light replaced the red the germination was recovered, but this reversibility did not reach to the germination level under the red light only. This result implied that other lights than red and far-red would play an important role on seed germination of annual bluegrass.

• Asian Journal of Turfgrass Science
• /
• v.6 no.2
• /
• pp.83-88
• /
• 1992

This study was carried out to determine the effect of peat and chemical fertilizer application on the growth of manilagrass and to obtain basic data for fertilization management of zoysiagrass. The results obtained are summarized as follows ; 1. Application of peat with chemical fertilizer increased the growth of tops and under of Manilareass compared with control or single application of peat or chemical fertilizer through the growing season. 2. The number of shoot was increased with amount of peat applied, and especially over 2 times with the application of peat 3,000 kg with compound fertilizer application plot compared with the control. 3. The higher amount of peat application, pH and organic matter content in soil where increased at the end of experiment. 4. Calcium and magnesium contents of soil in plot were increased as the amount of peat were applied, but sodium content appeared to be little difference according to the amount of peat applied.

• Asian Journal of Turfgrass Science
• /
• v.20 no.1
• /
• pp.93-105
• /
• 2006

The construction of golf courses has had adverse effects on the natural landscape and delicate ecosystem of Korea. Efficiency in planning and design was necessary to minimize the environmental impact of the original construction. However, the ordinal design methods have limited the data processing by the massive scale of the project of golf course development. Conventional design methods did not have a proper tool for alternative plans on pre-estimation of landscape destruction or minimizing of the environmental impact. Therefore, advanced computerized techniques need to be adapted for golf course design to solve the problems concerning the environmental impacts. Geographic information system (GIS) was applied on the process of geographical data input and analysis through the final outputs. Simulation works by the total database management enable the pre-investigation of the design In view of an assessment of environmental impacts. It is also possible to evaluate plans easily and propose the alternatives properly. Precise quantity calculation of engineering works by computer system should be guaranteed scientific, economic, and environmentally-sound.

• Korean Journal of Organic Agriculture
• /
• v.6 no.1
• /
• pp.133-149
• /
• 1997

Recently, the importance of management and cultivation of grasses has been increased in Korea. Among these cultural practices, the appropriate control of diseases is considered more important than other cultivation techniques such as fertilization and irrigation. The damages of brown patch and large patch caused by Rhizoctonia spp. and Pythium blight caused by Pythium spp. are serious in the major cultivation area of turfgrass in Korea. Since these diseases are difficult to control by agrochemicals, the damages are very serious if these are occured. The periodic spray of agrochemicals, to protect and control these diseases could make some problems of toxicity and environmental pollution as well as rising of non-target diseases. Therefore, the biological methods to control diseases have been required to decrease problems resulted from overuse of agrochemicals, to conserve natural ecosystem, and to control effectively diseases of grasses in the long period. The number of studies about biological control using antagonistic microorganisms have been increased for last half century. However, the application of biological control method has been very limited. In this study, thirteen isolates of R. cerealis, 8 isolates of R. solani and 3 isolates of Phthyn spp. have been isolated from diseased turfgrass in golf course and grass-culture area that have patch and wilting symptoms of zoysia grass and creeping bentgrass. Isolation frequency of R. cerealis and R. solani was high in especially zoysiagrass, while Pythym spp. was isolated from bent grass at low frequency but showed high pathogenicity. Totally, 205 isolates of soil microorganisms were isolated in this study as primary antagonistic microorganism by Herr's triple agar layer plate and dual culture method using rhizosphere of grasses, soil of crop field as the source of antagonistic microorganisms. Among the 205 isolates, 23 isolates were actinomycetes and 182 isolates were bacteria. All of the actinomycetes were isolated by Herr's method. Antagonistic effect of primary isolated microorganisms was tested for in vitro mycelial growth inhibition against pathogenic fungi isolated from grasses and for inhibition of disease occurrence in 24 well tissue culture plate and pot experiment. Then, four isolated of bacteria which are BG23, BG74, BG136 and BG171 were selected as antagonistic microorganisms against soil-born pathogenic fungi of bentgrass.