• Research in Plant Disease
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• v.14 no.1
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• pp.43-50
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• 2008

Rhizoctonia blight (large patch) caused by Rhizoctonia solani AG2-2 is one of the major diseases on zoysiagrass in golf courses. In this study, anatgonistic bacteria to R. solani AG2-2 were selected in vitro tests using confrontation bioassay and triple layer agar diffusion method. The most active bacteria, Bacillus subtilis CJ-9 were tested for controlling large patch in pots. Relative Performance Indies (RPI) was used as a criterion for the selection of potential biocontrol agent. B. subtilis CJ-9 showed resistance to major synthetic agrochemicals used in golf course. In field tests at golf course, B. subtilis CJ-9 was more effective in suppression of large patch severity and population development of R. solani AG2-2 in soil than chemical fungicides. B. subtilis CJ-9 could be an alternative to chemical fungicides for eco-friendly management of large patch on zoysiagrass.

• Journal of the Korean Wood Science and Technology
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• v.44 no.3
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• pp.323-336
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• 2016

This study was carried out to evaluate the physicochemical properties of steam exploded wood chips for peat moss substitute in vegetation media. Also, the mixtures at the different ratios of peat moss and pretreated wood chips (90 : 10, 70 : 30 and 50 : 50 (w/w), respectively) were evaluated by physicochemical and plant growth characteristics. The pretreated wood chips was showed that bulk density, porosity and pH were $0.26g/cm^3$, 93.3% and 5.7, respectively. This result indicates that physicochemical properties was improved when wood chips was apply to steam explosion in the range of optimum physicochemical condition for vegetation media. In particular, the mixture ratio of peat moss and pretreated wood chips to 70 : 30 (w/w) showed higher seed germination, plant height and leaf growth than peat moss. Also, the bulk density, porosity, water holding capacity, pH and C/N ratio were $0.20g/cm^3$, 91.8%, 76.1%, 5.2 and 51.0 in the range of optimum physicochemical condition for vegetation media.

• Korean Journal of Weed Science
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• v.4 no.2
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• pp.163-168
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• 1984

This study was conducted to find out the effect of paclobutrazol 0.6G and flurprimido 50wp application at 40 days before heading on the characters related with lodging and the growth and yield of paddy rice plants in 1983. The culm length were shortened by paclobutrazol and flurprimido applications and high level of suppression was observed in the 3rd to 5th internodes. Paclobutrazol caused thiner internode and thicker wall of internode than the untreated control, however flurprimido caused thicker wall of internode without change of internode diameter. The breaking weight of lower internode was higher by flurprimido application than those by the untreated control and paclobutrazol application. The lodging indexes effected by both chemicals were remarkably decreased, and also the field lodging was not observed. The leaf area indexes effected by paclobutrazol and flurprimido applications were increased because of the increasing of tillers and green leaves per stem in spite of shortening of lead blades. Paclobutrazol and flurprimido application out-yielded significantly the untreated control lodged at grain filling stage. However in conditions of untreated with no lodging, the yields of these treatments were significantly less than that of untreated control.

• Korean Journal of Weed Science
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• v.17 no.3
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• pp.288-294
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• 1997

Field and pot expeiments were carried out to evaluate the interaction between quinclorac and bensulfuron-methyl on growth of the rice plants(Oryza sativa L. cv. Choocheongbyeo) at 20, 45, 65 days-old stages. Quinclorac and bensulfuron-methyl showed antagonistic interaction at both stages, which were detected by the Chisaka's method at isobles of 10% growth inhibition. The antagonism indices were -0.63 and -1.67 at 20 and 65 days-old seedling stages, respectively. Leaf-rolling of rice occurred when quinclorac was applied at 600g ai/ha or more at 20 days-old seedling stage, while it occured at the dose of 900g ai/ha at 65 days-old stage. Bensulfuron-methyl reduced plant height and dry weight as well as tiller production at both stages. Leaf-rolling of rice was reduced when mixture of quinclorac and bensulfuron-methyl was applied due to antagonism of the two herbicides. High temperatures increased the phytotoxicity of bensulfuron-methyl, while the phytotoxicity caused by quinclorac alone was not responsive to temperature. The antagonistic effect between quinclorac and bensulfuron-methyl increased at low temperature as tested by the Colby's method.

• Korean Journal of Weed Science
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• v.12 no.1
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• pp.31-38
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• 1992

This study was conducted to investigate the effect of plant growth retardants on the growth and characters related with lodging in rice. The results are summarized as follows. Plant height which is closely related to lodging was significantly inhibited by the application of inabenfide, paclobutrazol, and uniconazole. Among the tested application times, inabenfide, paclobutrazol, and uniconazole were the most effective in inhibiting plant height at 30, 20, 20 days before heading respectively. Inabenfide was markedly effective in reducing the lower (4th) internode length, whereas paclobutrazol and uniconazole were more effective in reducing the upper (3rd and 2nd) internode length. Internode wall of rice plant treated with chemicals was tended to be thickened as compared with control. Heading date was not influenced by inabenfide, but paclobutrazol and uniconazole were inhibited 1 or 2 days in heading date as compared with control. Lodging index was the most reduced when inabenfide was applied 30 days before heading with 160g ai whereas paclobutrazol and uniconazole were applied 15 days before heading with 12, 1.2g ai per 10a, respectively. All the treatments inhibited the lodging of rice but control was completely lodged. Yield treated with these chemicals was prevented by 10-12% of yield decrease occurred by lodging. As a conclusion, inabenfide with 120 or 160g ai at 40 or 30 days before heading, paclobutrazol with 12g ai at 15 days before heading, arid uniconazole with 1.2g ai at 15 days before heading appear to be the most practical application time and rate for preventing lodging in paddy rice.

• Korean Journal of Weed Science
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• v.4 no.1
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• pp.19-25
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• 1984

Emergence, growth of weeds and growth, yields of rice (cv. Sam Seung Byeo) were determined at different transplanting times and nitrogen levels. Dominant weed species were Cyperus difformis, Rotala indica, Monochoria vaginalis, Cyperus serotinus, Sagiitaria pygmaea, Scirpus hotarui, and Fimbristylis miliacea. Number of weeds was increased in earlier transplanting time and but decreased in high nitrogen level. Dry weight of weeds was decreased with increase of nitrogen level at early transplanting time (May 26) but increased at nitrogen 8 or 16㎏/10a, Plant height, dry weight, leaf area index, and yield of rice were decreased as transplanting time was delayed but increased as nitrogen level increased. Yield reduction of rice due to weed competition was increased in earlier transplanting time and decreased in high nitrogen level.

• Korean Journal of Weed Science
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• v.8 no.3
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• pp.324-329
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• 1988

This experiment was conducted to find the effect of paclobutrazol application of 12, 18, 24g/10a at 35, 25 and 15 days before heading on the characters related with lodging, growth and yield of paddy rice plants in 1985. Culm lengths were reduced from 7% to 12% by paclobtrazol application of 35, 25 and 15 days before heading. The paclobutrazol caused more short internode, thick well of internode and wide section area of internode than the untreated control. The lodging index were remarkably decreased by paclobutrazol application and also the field lodging of rice plant was not observed. The number of spikelet per panicle was decreased by paclobutrazol application at 35 days before heading and 25, but ripened grain ratio and 1000 grain weight were higher than the untreated control. Paclobutrazol applications increased more from 5% to 8% than untreated control on the grain yield.

• Korean Journal of Weed Science
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• v.18 no.1
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• pp.63-68
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• 1998

This experiment was carried out to select some herbicides for edible wild greens, Album monanthum, Petasites japonicus, and Aster scaber. The herbicides tested were napropamide 21.8% EC, nitralin 50% WP, and pendimethalin 31.7% EC. Dorminant weeds in the field were Echinochloa crus-galli, Digitaria sanguinalis, Persicaria hydropiper, Chenopodium album, and Siegesbeckia pubescens. Simpson's index was calculated to 0.26~0.30, which showed that weed occurrence in the field was quite various. Control efficacy in the field treated with napropamide EC 872g(ai/ha)., nitralin WP 1,000g(ai/ha), and pendimethalin EC 634g(ai/ha) were 81.4%~85.6%, 79.4%~82.8%, and 86.8%~92.2%, respectively. The typical phytotoxic symptoms to herbicides were germination inhibition, growth retardation, and malformation.

• Korean Journal of Weed Science
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• v.7 no.2
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• pp.171-178
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• 1987

This study was conducted to examine the possibility of complete lodging. prevention, the growth and yield of the paddy rice plant by paciobutrazol 0.6%G application at 15 days before heading under the several levels (0, 5, 10, 15, 20, 25, 30, 35, 40, 45 kg/10a) of nitrogen fertilizer in 1986. Culm length was shortened 10-15% by paclobutrazol application. The shortened rate of internode was very extreme on the 3rd and 4th internode in paclobutrazol application. Moment the height of center gravity and lodging index turned higher with increasing nitrogen fertilizer, on the other hand, those of paclobutrazol application were smaller than control. Lodging degree (0~4) was 1~3 above 25kg/10a level of nitrogen fertilizer in control, however, no more than 1 at 45kg/10a level of nitrogen fertilizer in paclobutrazol application. Ripened grain ratio and grain weight of paclobutrazol application were larger than those of control. Yield increased more 15-26% in paclobutrazol application than control. The nitrogen level of maximum yield was about 25kg/10a in control, but was 31kg/10a in paclobutrazol application.

• Korean Journal of Weed Science
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• v.9 no.3
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• pp.183-200
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• 1989

An experiment was conducted at the greenhouse of the International Rice Research Institute in 1987 to find out the character of dry matter production, the potential seed production ability and the ecological and physiological strategies to adaptation. For these, two rice cultivars, IR64(lowland rice) and UPLRi-5(upland rice), and seven weed species were used ; Echinochloa glabrescens Munro ex Hook. f., E. cress-galls ssp. hispidula (Retz.) Honda, E. colons (L.) Link, Monochoria vaginalis (Burin. f.), Ludwigia octovalvis Jacq.) Raven, Fimbristylis miliacea Vahl and Cyperus difformis L. Adaptation strategies of weed species varied by species. However, they had efficient seed production strategy through different ways. In general, sedge weed species (F. miliacea and C. difformis) produced great amount of seeds at the expense of seed size through greater ratooning ability and low relative dry weight for flowering. For broadleaved weed species, greater number of descendants were obtained through high plasticity and low relative dry weight for flowering (M. vaginalis) or greater growth ability through effective photosynthetic efficiency (L. octovalvis). Grass weed species, on the other hand, produced their seeds through effective growth (net assimilation rate and relative growth rate), high ratooning ability (except E. crus-galls ssp. hispidula) or low relative dry weight to maximum dry weight for flowering (E. glabrescens). The harvest indices of the weed species were considerably lower than those of rice. Fimbristylis miliacea had the greatest ratooning ability followed by C. difformis, E. colons and E. glabrescens. The greatest seed productivity was recorded by C. difformis (279, 000) and L. octovalvis (268,000) while rice produced the least number of seeds (1300-6100). Log seed weight had a negative linear relationship with log seed number (y=6.30-1.48X, $R=-0.965^{**}$). For all species plant plasticity response was not directly correlated with mortality response.