• Journal of Ecology and Environment
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• v.47 no.4
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• pp.250-260
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• 2023

Background: Crabgrass (Digitaria ciliaris, Poaceae) is a globally distributed weed, including in Afro-Eurasia, America, and Australia. As a highly gregarious plant, crabgrass is an important habitat for a diverse array of insects, and a potential habitat for agricultural pests. To compare the insect communities associated with the crabgrass community, insects were sampled using sweep sampling (100 sweeps per sample) at five sites, including Daejeon (Daejeon and Gap rivers), Anseong, Namhae, and Inje, with a focus on the Daejeon River. Results: A total of 5,888 individual insects belonging to eight orders, 42 families, and 115 species were collected from the five sites. Both the number of species and individuals of Hemiptera were the highest at all of the sites. In the present study, 73% of the insect population fed on D. ciliaris as a host plant. The dominant species in the D. ciliaris community was Laodelphax striatellus (Delphacidae), being ubiquitous at all the sites which showed a high abundance of rice pests in the communities and the suitability of D. ciliaris as an alternative host plant for them. The Shannon-Wiener diversity index was highest in Inje on 17 September (2.88), and the Chao1-bc diversity index was highest in the Gap River on 5 September (80). The sampling efficiency of 100 sweep samples (sample coverage) was calculated to be as high as 90%. The results of the samples taken from September to November in the Daejeon River showed that the number of species and individuals decreased gradually over time, and the number of dominant species decreased sharply between September and October. Similarity analysis indicated that sampling dates that were closer together yielded sampled assemblages with higher faunal similarity. In addition, in each sampling, the difference in the minimum temperature during the two-week period prior to sampling and faunal similarities were negatively correlated. Conclusions: This study provides foundational data that could enhance our understanding of insect diversity in D. ciliaris. The data can facilitate ecological conservation and management of Korean grasslands generally, as well as identification of potential pests that may disperse from D. ciliaris communities to nearby farmland.

• Journal of Ecology and Environment
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• v.33 no.4
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• pp.317-323
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• 2010

Nutrient availability is a critical component of agroecosystems, and is relevant to both above- and below- ground interactions. The principal objective of this study was to determine how the cessation of fertilization affects the communities of weeds and soil organisms in a corn/wheat field. Changes in dominant weed species, substrate-induced respiration, and the population density of nematodes and microarthropods were evaluated. Microbial substrate-induced respiration (SIR) and the population density of microarthropods decreased following the cessation of fertilization and were partly correlated with the aboveground weed biomass. The cessation of organic fertilizer application but continuing application of inorganic fertilizer reduced the population density of nematodes. In response to the cessation of fertilization, weed communities were dominated by species with little dependency on fertilization. Amaranthus retroflexus was identified as the most dominant species in the corn field; however, it was replaced by Digitaria ciliaris after the cessation of fertilization. In the wheat field, the cessation of fertilization led to a rapid reduction in the biomass of most weeds, except for Vicia angustifolia, supposedly as the result of symbiotic nitrogen fixation. Additionally, the fact that weed biomass was partially correlated with SIR or the population density of microarthropods may reflect a mutual feedback between soil organisms and weeds. The results indicate that the cessation of fertilization alters communities of weeds and soil organisms through changes in weed biomass and interactions with symbiotic microorganisms.

• Weed & Turfgrass Science
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• v.1 no.4
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• pp.38-43
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• 2012

This study was conducted to predict the yield response of red pepper and to determine the economic weed threshold levels for red pepper cultivation field from competition with the most serious weeds, Amaranthus patulus and Digitaria ciliaris in Youngyang of Korea. Crop yield as a function of weed density was predicted by using a rectangular hyperbola, and their economic threshold levels were determined by using the equation developed by Cousens (1987). The red pepper yield loss models of weeds were predicted as y=304.7/(1+0.063x), $R^2$=0.967 in D. ciliaris and y=281.3/(1+0.1723x), $R^2$=0.952 in A. patulus. Economic thresholds calculated using Cousens' equation were negatively related with the competitiveness of weed. Economic thresholds of each weed were calculated as 18.2 plant $100m^{-2}$ in D ciliaris, and 7.2 plant $100m^{-2}$ in A. patulus.

• Weed & Turfgrass Science
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• v.6 no.3
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• pp.212-221
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• 2017

An actinomycetes isolate G-0299 obtained from a forest soil showed strong phytotoxic activity to Digitaria ciliaris. For the foliar application study, the culture filtrate of the isolate G-0299 showed strong herbicidal activity only to D. ciliaris among the 12 monocot and 5 dicot weed species. And herbicidal activity at a concentration of 500, 250, 125 and $62.5{\mu}gmL^{-1}$ of culture filtrate was 100%, 98%, 70% and 40%, respectively. Phytotoxic symptoms of the culture filtrate by foliar application were desiccation and burn-down or bleaching of leaves and finally plant death. And then the herbicidal activity was exhibited only under the light condition. Also, chlorophyll loss of D. ciliaris leaf tissues in the light condition was much higher than in the dark condition and then chlorophyll content decreased 82%, 5%, respectively. In conclusion, our results suggest that soil bacteria, isolate G-0299 could be a good candidate for new bio-herbicide and provide a new lead molecule for a more unique herbicide.

• Journal of the Korean Institute of Landscape Architecture
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• v.33 no.1 s.108
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• pp.71-80
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• 2005

In order to search for ecologically indicative characteristics on the street tree plots in Daegu area, plant communities and their floras were investigated. A total of 105 plots were collected and numerically analyzed by PCoA(Principal Coordinates Analysis). These plots were classified into 4 types containing 139 species, 97 genera, 42 families(including 37 exotic species): urban-dry type, urban-wet type, rural-dry type, rural-wet type. Habitat connectivity to the surrounding vegetation cover, extent and frequency of human impacts, and soil moisture recognizably were the main factors to allow the plots differentiation. Indicative species composition to these four types was generated as Eleusine indica-Eragrostis multicaulis-Oxalis corniculata to the urban-wet, Digitaria ciliaris-Eleusine indica-Eragrostis multicaulis to the urban-dry, Setaria viri-dis-Artemisia-Lactuca indica var. laciniata to the rural-wet, and Setaria viridis-Digitaria ciliaris-Erigeron canadensis to the rural-dry, respectively. Mean species number per plot for rural type was 2.5 times higher than for urban types. Street tree species representative to the rural-wet type is Zelkova serrata, which is a key species of potential natural vegetation in the alluvial land of Daegu area. Street tree plots were characterized by Eleusine indica showing the highest r-NCD value and also C4-assimilation grass plants. Views on the efficacy of the rural-wet type and the reinforcement of vegetation connectivity and soil moisture in rehabilitating street tree plots, are discussed.

• Korean journal of applied entomology
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• v.43 no.4 s.137
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• pp.267-273
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• 2004

To select indicator insects, the abundance of which is one of the major criteria for the evaluation of agricultural environment, was designated and monitored in the three sites (Hongcheon A, B, and Yangpyeong) from 2001 to 2003. Characteristics of rice cultivation are usual cultivation with 2 or 3 times sprayed chemical agents per year in Hongcheon A site, duck cultivation with non-sprayed chemical agent, green manure and mowing in Hongcheon B site, and pond snail with non-sprayed chemical agent, green manure and mowing in Yangpyeong site. Dominant floral species are Digitaria ciliaris (Retz.) Koel., Persicaria thunbergii (Siebold & Zuccarini) H. Gross, Echinochioa crus-galli (L.) Beauvois, and Humulus scandens (Lour.) Merr. in Hongcheon A site, Digitaria ciliaris (Retz.) Koel., Persicaria thunbergii (Siebold & Zuccarini) H. Gross, and Echinochloa crus-galli (L.) Beauvois in Hongcheon B site, and Digitaria ciliaris (Retz.) Koel., Setaria viridis (L.) Beauv., and Persicaria langiseta (De Btuyn) Kitagawa in Yangpyeong site. Degree of green naturality (DGN) was higher in Hongcheon B site (2.0) and Yangpyeong site (3.6) than in Hongcheon A site (1.6). Number of species and individual of insects collected in the three sites were abundant on August and September. The species diversity was higher in Hongcheon B and Yangpyeong than in Hongcheon A. And Coleoptera was dominant in the all sites. The dominance index (DI) was the lowest, but diversify index (H'), evenness index (E) and richness index (RI) were the highest in Hongcheon B site. Based on three results, indicator insects for the evaluation of agricultural environment were selected as Dolichus halensis in Hongeheon A site, as Pheropsophus. javanus and Polionemobius mikado in Hongcheon B and Yangpyeong sites.

• Asian-Australasian Journal of Animal Sciences
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• v.7 no.3
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• pp.335-342
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• 1994

This study was undertaken at Gowa, South Sulawesi, Indonesia, as part of a larger forage genetic resource evaluation project. The experimental program consisted of a field experiment where grass and legume species were grown in monocultures and the dry matter yield, rumen bag digestibility (RBDMD) and N content of leaf and stem components were monitored in the wet and dry seasons. Eight species of grass (Brachiaria decwnbens cv. Basilisk. Panicum maximum cv. Riversdale, Urochloa pullulans CPI 41192, Imperata cylindrica from Maiwa, South Sulawesi, Digitaria milanjiana CPI 41193, Cenchrus ciliaris cv. Malopo, Heteropogon contorlus and Setaria sphacelata cv. Splenda) were studied. P. maximum was the highest yielding grass in the wet season and B. decumbens in the dry season. The highest RBDMD in the whole plants were U. pulluians, P. maximum, S. sphacelata and D. milanjiana after 2 weeks regrowth in cycle I and S. sphacelata, B. decumbens, D. milanjiana and C. ciliaris in cycle 2. When total digestible DM was calculated for the whole of cycle I, P. maximum, B. decumbens and S. sphacelata were superior, but B. decumbens produced over twice as much as the other species in the dry season (cycle 2). The leaf N concentration of all grasses exceeded 1.0% (6.25% crude protein) in the regrowth in cycle I but did not exceed 0.5% in the dry season regrowth (cycle 2).

• Korean Journal of Weed Science
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• v.30 no.3
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• pp.183-190
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• 2010

The objective of this study was to isolate a herbicidally active compound from curly dock (Rumex crispus), a native weed in Korea and to identify its' chemistry. The $GR_{50}$ value of methanol extracts which is determined by a seed bioassay using rapeseed (Brassica napus) seedlings was $935\;{\mu}g\;g^{-1}$. Activity-directed isolation of ethylacetate extract led to the isolation of ECDA fraction with $GR_{50}$ value $53\;{\mu}g\;g^{-1}$. Based on data of GC-MS, $^1H$-NMR and $^{13}C$-NMR, the chemical structure of ECDA was determined as 2H-furo[2,3-H]-[1]-benzopyran-2-one which is known as angelicin. The $GR_{50}$ values of angelicin to barnyardgrass (Echinochloa crus-galli), southern crabgrass (Digitaria ciliaris), and indian jointvetch (Aeschynomene indica) were 426, 66 and $216\;{\mu}g\;g^{-1}$, respectively. Our results suggest that angelicin could be used as a lead compound for the development of new herbicides.

• Weed & Turfgrass Science
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• v.4 no.3
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• pp.209-218
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• 2015

This study was conducted to investigate the weed occurrence and distribution on the upland crop fields (garlic, barley, potato, maize, red pepper, soybean and Chinese cabbage) at 795 sites in Chungbuk province of Korea from Apr. to Oct. in 2014. From the result of this survey, 188 weed species in 42 families were identified and classified to 96 annuals, 40 biennials and 52 perennials. Based on the occurrence ratio, the most dominant weed species in Chungbuk province upland crop fields were higher in the order of Portulaca oleracea (8.14%), Digitaria ciliaris (6.72%), Echinochloa crus-galli (6.55%), Rorippa palustris (6.00%) and Chenopodium album (5.89%). The composition of major occurred weed families, Compositae, Poaceae, Polygonaceae and Cruciferae were 19, 10, 7 and 6%, respectively. In the winter upland crop fields, the dominant weeds were in the order of Capsella bursa-pastoris (12.36%), Alopecurus aequalis (11.05%) and Stellaria alsine (8.42%). In the summer upland crop fields, the dominant weeds were in the order of Portulaca oleracea (8.58%), Digitaria ciliaris (7.18%) and Rorippa palustris (6.28%). Fiftythree exotic weed species were identified. The results of this study could be useful information for estimation of future weed occurrence, weed population dynamics and establishment of weed control methods on the upland crop fields in Chungbuk province of Korea.

• Weed & Turfgrass Science
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• v.4 no.3
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• pp.199-208
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• 2015

This study was conducted to provide basic information for weed control by surveying the occurrence of weed species in upland crop fields in Gyeongnam province of Korea. The result of this survey, 55 weed species 21 families in barley fields, 56 weed species 22 families in garlic fields, 47 weed species 19 families in onion fields, 68 weed species 26 families in Chinese cabbage fields, 54 weed species 22 families in potato fields, 62 weed species 25 families in sweet potato fields, 87 weed species 29 families in red pepper fields, 79 weed species 28 families in corn fields, 84 weed species 29 families in soybean fields. The most dominant weed species in upland crop fields of Gyeongnam province were Alopecurus aequalis var. amurensis 20.7% (barley fields), Cardamine flexuosa 12.3% (garlic fields), Chenopodium ficifolium 18.7% (onion fields), Portulaca oleracea 8.1% (Chinese cabbage fields), Chenopodium ficifolium 13% (potato fields), Digitaria ciliaris 12.6% (sweet potato fields and red pepper fields) and Digitaria ciliaris 11.3% (corn fields), 13.2% (soybean fields). This information could be useful for establishment of future weed control methods in Gyeongnam province.