• Weed & Turfgrass Science
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• v.2 no.1
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• pp.1-7
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• 2013

Studies were carried out to provide basic information for establishing the weed control in Chungbuk, Korea. The present surveys targeting 260 farmers in Chungbuk province were conducted for the cultivation system, weeds occurrence and usage of herbicides. To estimate the occurring area of herbicide resistant weeds, soil samples from 400 paddy fields were collected twice on August, 2011 and April, 2012. In the results of survey, the 99.6% of farmers used the rice planting machine and the 78% of the farmers disseminated herbicides twice to control weeds before and after planting rice. The most commonly used herbicide were as follows; soil-applied herbicide : butachlor 46.6%, mid-term herbicide : mefenacet + pyrazosulfuron-ethyl 10.7%, foliar herbicides : bentazone 62%. The dominant paddy field weeds included Echinochloa crusgalli (16.2%), Scirpus juncoides (12.2%), Monochoria vaginalis (11.9%) and Sagittaria trifolia (9.5%). Occurrence area of sulfonylurea herbicide resistant weeds was 13,659 ha in 26.8% of the paddy area. Monochoria vaginalis showed the highest with 4,605 ha (36.4%) followed Scirpus juncoides (30.7%), and Lindernia dubia (10.6%) at 2011. Monochoria vaginalis and Scirpus juncoides occurred were evenly distributed and the most problematic weed in Chungbuk, Korea.

• Parasites, Hosts and Diseases
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• v.28 no.3
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• pp.161-174
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• 1990

The complete life cycle of Spirometra erinacei has been experimentally maintained in the laboratory. The cyclops were reared as the first intermediate host, and the tadpoles of Rana nigromaculata as the second intermediate host. ICR mice were used as another second host. The experimental definitive hosts were dogs and cats. Maturation and hatching of the eggs took 8 to 14 days by incubation at 29℃. The coracidium measured 43.8×36.9㎛. Mesocyclops leuckarti and Eucyclops serrulatus were susceptible to the coracidial infection. The procercoids older than 5 days in the cyclops had minute spines at the anterior end, calcium corpuscles in the body parenchyme and the cercomer at the posterior end. Procercoids 10 to 20 days old were infective to tadpoles, and 15 or 21 day old worms could infect the mice. The plerocercoids from the tadpoles at 15 days after experimental infection were pear-shaped and shorter than 1 mm in the length and were infective to mice. Fifteen to 18 days after experiMental inoculation of plerocercoids to dogs or cats, the adult worms began to produce eggs. One life cycle from egg to egg needed 48 to 67 days in the laboratory. The morphology of larval or adult worms was compatible with the description of Spirometra erinacei.

• Korean Journal of Ecology and Environment
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• v.53 no.3
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• pp.221-228
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• 2020

We studied the development of the endangered gold-spotted pond frog, Pelophylax chosenicus eggs and analyzed growth and survival rate of the tadpoles while feeding different feed to obtain the basic data on the its biological traits and reproduction. We observed the fertilized eggs of gold-spotted pond frog that naturally spawned in a breeding tank using a microscope. Fertilized eggs were sphere shape surrounded by colloid layers, clearly distinct with animal and plant poles. The fertilized eggs hatched 31 hours after fertilization and operculum complete at 175 hours after fertilization at water temperature of 27.0±1.0℃. As a result of growth and survival rate by different feed from 35 days after mouth open stage, vegetable feed (VF) group and tetra-min (T) group were significantly higher average weight gain rate (WG)(5843.9% and 5736.3%, respectively) and average specific growth rate (SGR) (11.67% and 11.62, respectively) compared with other groups (WG: 641.8~4625.2%, SGR: 5.72~11.01%). The vegetable (V) group showed the lowest growth rate (P<0.05). The average feed efficiency was 177.83% in the VF group, about 17 times higher than the V group. In addition, the average survival rate of the VF and T groups were the high at 97.5% and 100%, respectively, and the V group was the lowest at 32.5%. Therefore, the more efficient feeds for successful breeding is singly with VF or T.

• Weed & Turfgrass Science
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• v.2 no.4
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• pp.352-357
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• 2013

A survey was performed to investigate major paddy field weeds and frequently used herbicides in Gyeonggi province, Korea in order to establish a system to efficiently control herbicide-resistant weeds. The dominant paddy field weeds included Echinochloa spp. (22%), Eleocharis kuroguwai (14%), Sagittaria trifolia (13%), Scirpus juncoides (12%), Monochoria vaginalis (9%) and Sagittaria pygmaea (7%), and the most widely used herbicides were butachlor 33% CS (25%), benzobicyclon + fentrazamide + imazosulfuron 11.5% SC (9%), cyclosulfamuron + mefenacet 22.2% SC (9%), butachlor 5% GR (6%), and oxadiazon 12% EC (6%) in Gyeonggi province, Korea. Many paddy rice growers considered S. juncoides, M. vaginalis, S. pygmaea and C. difformis as herbicide-resistant weeds. An extensive research deserves to be conducted to monitor occurrence of herbicideresistant paddy weeds in Gyeonggi province, Korea.

• Parasites, Hosts and Diseases
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• v.26 no.3
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• pp.179-188
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• 1988

The life cycle of Fibricola seoulensis was studied in the laboratory and in the field, with special interests in the larval developments within the eggs and in the intermediate hosts. The first emergence of miracidia after incubation of eggs in 26C water began on the ninth day. The miracidia, elongate and cylindrical shape, had epidermal plates in the formula of 6, 9, 4 and 3, with two pairs of flame cells and lateral processes. A kind of fresh water snail, Hippeutis (H.) cantori, was found to shed furcocercous cercariae from the 13th day after experimental challenge with miracidia while Physa acute failed to shed. The same kind of snail collected from the field also shed the same cercariae. The cercariae were equipped with 2 pairs of penetration glands and 5 pairs of fame cells. The tadpoles of Rana nigromaculata were found susceptible to experimental infection with the cercariae. The same kind of tadpoles collected from various areas were also found naturally infected. The metacercariae in the tadpoles which were infected experimentally became infective to the definitive host in 21 days. The metacercariae were located free in the body cavity of tadpoles, and attained sexual maturity in rats in 7 days. The present study successfully followed the complete life cycle of F. seoulensis and found that it is possible to maintain the life cycle in the laboratory.

• Korean Journal of Weed Science
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• v.16 no.1
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• pp.8-13
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• 1996

This study was conducted to know the effect of storage period, harvesting time and light condition on dormancy breaking of major weeds. Echinochloa crus-galli, Cyperus serotinus, Aeschynomene indica, Ludwigia prostrata and Bidens tripartita had the 10 or 30% germination ability within 30 days after harvest but scirpus juncoides, Potamogeton distinctus, Aneilema japonica and Monochoria vaginalis had not germination untill 120 days after harvest of seed. C. serotinus and P. hydropiper required strong light for germination but S. juncoides, L. prostrata and B. tripartita showed the less tham 5% germination in the dark condition gerntinator. S. juncoides germination showed negative response in chemical soaking but A. japonica, B. tripartita and L. prostrata showed high germination percentage in Acetone, Chloroform and distilled water soaking during the 10 days after treatment.

• The Korean Journal of Pesticide Science
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• v.10 no.4
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• pp.320-328
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• 2006

This study was conducted to evaluate the herbicidal efficacy of flucetosulfuron+pyrazosulfuron-ethyl against Eleocharis kuroguwai and Scirpus planiculmis and to investigate tank-mix of flucetosulfuron + pyrazosulfuron-ethyl with bentazone and 2,4-D to control sulfonylurea resistant Monochoria vaginalis and Scirpus juncoides. In controlling E. kuroguwai, flucetosulfuron + pyrazosulfuron-ethyl showed 75% control, lower than that (95%) of bentazone + MCPA, at 29 DAA (days after application), while at 60 DAA it showed 90%, greater than that of (78%) of bentazone + MCPA, with greater control than penoxsulam at all times. In case of Scirpus planiculmis control, flucetosulfuron + pyrazosulfuron-ethyl showed lower activity than bentazone + MCPA but greater than penoxsulam. Flucetosulfuron + pyrazosulfuron-ethyl showed consistently high activities against Echinochloa crus-galli and E. kuroguwai regardless of soil flooding condition, while penoxsulam and bentazone + cyhalofop showed significantly lower activity in 5 cm flooding condition than 0 cm flooding condition. Flucetosulfuron + pyrazosulfuron-ethyl did not control sulfonylurea resistant Monochoria vaginalis and Scirpus juncoides, while its tank-mix with bentazone or 2,4-D at 2/3 or 1/2-folds of their recommended rates, respectively, provided > 90% control.

• Weed & Turfgrass Science
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• v.2 no.2
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• pp.131-137
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• 2013

The study was carried out to obtain the basic information on distribution and occurrence of weeds including resistant weeds to sulfonylurea herbicides in paddy fields of Gyeongbuk province. In weed distribution on life cycle, annual weed was occupied by 91.8% and perennials were 8.2%, respectively. In morphological distribution of weeds, broad leaf weeds were 85.7%, sedges was 9.1%, and grass weed was 3.8%, respectively. Sulfonylurea-resistant weeds in paddy fields of twelve regions were widely occurred except for Yecheon region. The six sulfonylurea resistant biotypes occurred in paddy fields of Gyeongbuk province were Lindernia dubia, Eleocharis kuroguwai, Monochoria vaginalis and Ludwigia prostrata. It revealed that occurrence rate and area of sulfonylurea-resistant weeds were about 15.9 % and 22,420 ha in Gyeongbuk province.

• Animal Systematics, Evolution and Diversity
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• v.11 no.2
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• pp.167-182
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• 1995

The species of Cumacea; Dimorphotylis asiatica, D. valida and D. acroplicata which are new records from Korea, are redescribed.

• Korean Journal of Weed Science
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• v.32 no.1
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• pp.52-56
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• 2012

The occurrence of sulfonylurea-resistant weeds has recently increased in Korea. A survey was performed to investigate major paddy field weeds and frequently used herbicides in Gangwon province, Korea in order to establish a system to efficiently control herbicide-resistant weeds. The dominant paddy field weeds included Monochoria vaginalis (14%), Sagittaria trifolia (14%), Scirpus juncoides (13%), and Echinochloa spp. (13%), and the most widely used herbicides were oxadiazon 12% EC (27%), butachlor 5% GR (20%), oxadiargyl 1.7% EC (16%), and benzobicyclon+imazosulfuron+pyriminobac-methyl 6.1% SC (14%) in Gangwon province, Korea. Many paddy rice growers considered Scirpus juncoides, S. trifolia, Echinochloa spp. and M. vaginalis as herbicide-resistant weeds. An extensive research deserves to be conducted to monitor occurrence of herbicide-resistant paddy weeds in Gangwon province, Korea.