• Asian Journal of Turfgrass Science
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• v.20 no.2
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• pp.167-174
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• 2006

This study was initiated to investigate the effect of chitosan on creeping bentgrass growth. Chitosan was applied several times in dilution of 300, 500 and 800 times at ten-day intervals after transplanting. Such growth characteristics as leaf length, root length, numbers of leaves, fresh weight and dry weight and chlorophyll content were observed. Treatment of 500 times diluted chitosan resulted in the longest root length, being 31.5cm while the control the shortest root of 25.1cm. Leaf numbers were 27.9 and 45.5, respectively for the control and the 300 times treatment. The highest chlorophyll content was associated with treatment of 300 times diluted chitosan and the lowest one with the control, resulting in 11.9 and $18.4mg/100cm^2$, respectively. We found that leaf number, chlorophyll content, fresh and dry weight were higher in the treatment of 500 times than the other treatments.

• Asian Journal of Turfgrass Science
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• v.9 no.3
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• pp.235-252
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• 1995

Turfgrass Rhizoctonia blight is a severe disease in golf courses in Korea. Attempts were made in 1989 to 1994 to identify the Rhizoctonia species associated with turfgrass blights and also to examine their epidemiology. A total of 120 Rhizoctonia isolates collected were identified as R. solani AG1, R. solani AG2-2, R. cerealis(AG-D) and R. oryzas from brown patch, large patch, yellow patch and white patch, re-spectively. R. solani AG1 was mostly associated with brown patch of cool-season grasses. and most frequently isolated in June through July and also in September. R. solani AG2-2 was isolated exclusively from zoysiagrasses from April to November, most frequently in June through July and October through November. R. cerealis was isolated frequently from both creeping hentgrass in March through April and in November, and zoysiagrass in April and July. Thermophilic R. oryzae was isolated only from creeping bentgrass in August, although with very low frequency. R. solani AG2-2 was strongly pathogenic specifically to Korean lawngrasses(Zoysia japonica, Z.matrella, Z. tenuifolia), but non-pathogenic to creeping bentgrass(Agrostis palustris), bermudagrass (Cynodon dactylon), Kentucky bluegrass(Poa pratensis), perennial ryegrass(Lolium prenne), and creeping red fescue(Festuca rubra subsp. ruhra L.). R. cerealis was strongly pathogenic to zoysiagrass and bentgrass only, but was isolate-specific i.e., from non-pathogenic to pathogenic, for other turfgrasses. The mycelial growth was optimum at relatively high temperature ranges of 25~30$^{\circ}C$ for R.solani AG1, AG2-2 and R. oryzae, while the mycelial growth of R. cerealis was initiated at $^{\circ}C$ and almost ceased at or above $^{\circ}C$.

• Korean Journal of Weed Science
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• v.16 no.3
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• pp.221-229
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• 1996

This study was carried out to determine the effects of growth regulators, carbon sources and silver nitrate on callus formation and plant regeneration of turfgrass. The results were summarized as fallows : Callus from Korean lawngrass (Zoysia japonica Steud.) and pencross creeping bentgrass (Agrostis palustrir Huds.) induced better in MS medium than in N6 medium and by addition of 2,4-D than by that of NAA. Callus formation from Korean lawngrass and penncross creeping bentgrass was very effective at MS medium adding 1mg/L 2,4-D and at the medium adding 2mg/L 2,4-D, repectively. Growth of callus was good at MS medium containing 2mg/L 2,4-D+0.2mg/L NAA. Callus growth of Korean lawngrass and penncross creeping bentgrass was good when kinetin was added 0.2mg/L and 0.3mg/L, individually, to MS medium containg 2mg/L 2,4-D+0.2mg/L NAA. Regeneration rate from leaf and stock callus of Korean lawngrass was 44% at MS medium adding 2,4-D 2mg/L+NAA 0.2mg/L+kinetin 0.3mg/L and 32% at the medium containing 2,4-D 2mg/L+NAA 0.2mg/L+kinetin 0.3mg/L, each and that from leaf and stock callus of penncross creeping bentgrass was 80% and 67%, each, at the medium adding 2,4-D 2mg/l+NAA 0.2mg/L+kinetin 0.3mg/L. Regeneration rate of Korean lawngrass and penneross creeping bentgrass increased by 3 to 4% and by 10 to 16%, respectively, when added $AgNO_3$ 1~2mg/L to the above-mentioned regeneration medium.

• Weed & Turfgrass Science
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• v.4 no.3
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• pp.249-255
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• 2015

Trichoderma spp. were famous fungi used for turfgrass management in golf course. This study was conducted to evaluate effects of two microbial fertilizers containing Trichoderma harzianum and T. atroviride on the growth and quality of creeping bentgrass with turf color index, chlorophyll index, root length, shoot number, clipping yield and nutrient content. Treatments were designed as follow; non-fertilizer (NF), control fertilizer (CF), T. harzianum (TH), and T. atroviride (TA). Chlorophyll index and root length of TH and TA were increased than these of CF and shoot number and content and uptake of nitrogen (N) of TA higher than these of CF. The N content in turfgrass tissue was significantly related to shoot number, root length and N uptake (P<0.05) and shoot number was positively relate to chlorophyll index (P<0.05). These results indicated that application of Trichoderma harzianum and T. atroviride improved a growth and quality of creeping bentgrass by promoting N uptake.

• Asian Journal of Turfgrass Science
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• v.25 no.1
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• pp.43-47
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• 2011

Creeping bentgrass (Agrosis stolonifera L.) is regarded to be the most widely used cool-season turf grass species grown on golf greens and fairways in temperate climates of North America. Creeping bentgrass is highly susceptible to the fungal disease 'dollar spot' caused by Sclerotinia homoeocarpa. Dollar spot is a foliar disease favored by conditions of high humidity, warm days, and cool nights. Studies using Aliette Signature (Fosetyl Aluminum formulated with a green pigment) mixed with another broad-spectrum fungicide do not always provide additional visual quality benefits compared to the fungicide alone. The exact mechanism for improved summer visual quality, when it occurs, is not known. Fertility management and environment likely contribute. The object of this study is to evaluate fungicide strategies for control of dollar spot and effect on visual quality during summer and on an L-93/G-2 creeping bentgrass green. Nine fungicide combinations were used for this study. Disease control and visual quality by fungicides was evaluated on an established G-2/L-93 creeping bentgrass green at 3-hole Sunshine Golf Course in Lemont, IL. All fungicide combination showed excellent dollar spot suppression except Fore throughout the study. Visual quality of greens by addition of Aliette Signature is enhanced when bentgrass growth is compromised and slow. Dollar spot levels in Fore plots increased to 30% on 14 August, and was no different than untreated plots. Unacceptable quality by Fore was due to lack of dollar spot control.

• Asian Journal of Turfgrass Science
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• v.25 no.2
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• pp.202-207
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• 2011

Organic fertilizers are divided into natural organic and synthetic organics. The benefits of natural organic fertilizer were reported from the previous researches. However, the limited research results about clippings as a source of natural organic fertilizers were reported. The objective of the research to investigate effects of liquid fertilizer produced from fermented clippings for creeping bentgrass growth. Liquid fertilizer (LF) produced was used for the research to be compared with Urea and two natural organic fertilizers of different source (NO-1 and NO-2). Creeping bentgrass (Agrostis stolonifera L., L-93) was used for the study. Turfgrass quality was measured by visual evaluation every two weeks from June to October, 2011 using a scale of 1 to 9 (1=worst, 6=acceptable, and 9=best). Turfgrass disease damage was measured by percent of area damaged when a turfgrass disease occurred. LF produced lower damage than NO and urea when temperature was high. Although NO-2 produced the highest or equal to the highest turfgrass quality in June and October, LF had the highest or equal to the highest quality from July to September.

• Asian Journal of Turfgrass Science
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• v.25 no.2
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• pp.147-152
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• 2011

This study was conducted to evaluate the growth characteristics of creeping bentgrass cultivars for fairway of golf course at Yeoju area in Korea. At germination and coverage rate of creeping bentgrass, 'Shark' and 'CY-2' were excellent, 'L-93', 'Alpha', 'T-1 was in order', respectively. Visual qualities of 'Shark' and 'CY-2' also were excellent. Especially, 'Shark', 'T-1', and 'CY-2' showed excellent visual quality in summer days, the critical times for the bentgrass fairway quality. 'Shark', 'CY-2' and 'T-1' were excellent in Chlorophyll contents throughout the evaluation period. Chlorophyll content of 'T-1' was maintained very high in summer. 'CY-2' and 'Shark' showed the best root growth at the beginning of the study and contained longer and hairy roots. Which might make these two cultivars' water absorption easier than other's. NDVI (normalized difference vegetation index)of 'Shark', 'L-93' and 'CY-2' was excellent, respectively. 'T-1' showed the highest density and 'Shark', 'CY-2', 'Alpha', 'L-93' was followed by. The density of 'T-1' was rather increased in summer season, while those of other cultivars were decreased. Three diseases such as anthracnose, brown patch, and dollar spot, were appeared during the evaluation period. 'T-1' and 'L-93' were very sensitive to anthracnose which occurred at the beginning days of the study. The most susceptible cultivars to brown patch were 'Alpha' and 'L-93'. 'T-1' was the least resistant to dollar spot which occurred at the same time with brown patch.

• Asian Journal of Turfgrass Science
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• v.23 no.2
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• pp.241-252
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• 2009

This study was carried out to check the possibility of substituting bottom ash from the Seosan power plant for sand as growing media for creeping bentgrass (Agrostis stolonifera L.) under saline irrigation condition. Characteristics of growing media were evaluated by using column and leaching method. Creeping bentgrass cv. Pen-A1 was grown in pots with dredged up sand (DS) and bottom ash (BA) media those were amended using 1%, 2%, and 3 % OM rates in a green house. The plants were irrigated with 1.5 $dSm^{-1}$ saline water. Results showed that visual quality, plant height and shoot dry weight from DS treatment were higher than those of BA treatment. Even though BA contained more salts, repeated leaching could decrease ECe efficiently. In case of no OM amendment, the visual quality, plant height and shoot dry weight were similar between in BA and DS. Amendment of 2% OM increased the height of creeping bentgrass in DS, while decreased the plant growth in BA.

• Asian Journal of Turfgrass Science
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• v.22 no.2
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• pp.217-223
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• 2008

This study was conducted to figure out the effect of silicate as growth stimulator on growth of 'Pencrosss' creeping bentgrass. Creeping bentgrass(Agrostis palustris cv. 'Pencross') at the nursery of Sinwon Country Club was used. Silicate was applied at the concentration of 0, $200{\times}$, $500{\times}$, $1.000{\times}$. Polt size was 1 by 2 meter and there were three replications with completely randomized design(CRD). Creeping bentgrass growth was evaluated with visual turf grass quality, root length and No. of tiller density(ea/$cm^2$). Results of this study are as followings; 1. Average root length with silicate was $1.5{\sim}1.9cm$ longer than control. Especially, Root length of silicate was $7{\sim}8cm$ in summer. 2. Tiller density with silicate was $l8{\sim}22ea/cm^2$, $0.4{\sim}2.l$ less than control. But there was no significant difference. 3. Visual turfgrass quality with silicate was $5.0{\sim}8.3$, $0.3{\sim}1.5$ higher than control. But there was no significant difference. In conclusion, silicate might be grown as root growth stimulator of creeping bentgrass during summer in Korea. However, this study was conducted under one year. Accordingly, in-depth experiment should be done over several years.

• Asian Journal of Turfgrass Science
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• v.22 no.2
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• pp.149-160
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• 2008

This study was carried out to examine the growth performance of 10 cultivars of creeping bentgrass under salt injury in Seo-san reclaimed area. Turfgrass performance studies included 10 creeping bentgrass cultivars (T-1, L-93, Penn A1, Pennlinks II, Seaside II, Declaration, Penn A4, Crenshaw, Dominant, and Penncross). Ten creeping bentgrass cultivars were grown on a USGA recommended research green. Plots were seeded on May 31, 2006 at the rate of $7\;g{\cdot}m^{-1}$. Electric conductivities of irrigation water (ECw) and soil (ECe) were ranged from 0.28 to $3.3\;d\;S{\cdot}m^{-1}$ and from 0.25 to $3.5\;d\;S{\cdot}m^{-1}$ respectively. Leaf color, turf quality, coverage rate, and growth rate were checked under the salty condition in reclaimed land for 2 year. Creeping bentgrass cultivars of T-1, Penn links, and Crenshaw presented dark green color and Penn A1, Declaration showed lighter green color. Penn A1, Penn A4 and L-93 exhibited the highest overall turfgrass quality. Average visual coverage was 75.3% after eleven weeks after seeding. Dominant, L-93, and Penn A1 resulted in higher visual coverage compared to the other cultivars. There was no difference in density among cultivars at 1 year after establishment. However, Declaration, Penn A1, T-1, and L-93 showed higher density compared to the other cultivars at 2 years after seeding. Creeping bentgrass showed different quality, density and color in salty soil (ECe: $0.25-3.5\;d\;S{\cdot}m^{-1}$) and from application of salty irrigation water (ECw: $0.28-3.3\;d\;S{\cdot}m^{-1}$) conditions. These results will be useful where selecting green cultivars for the golf courses in reclaimed land area.