• Korean Journal of Agricultural Science
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• v.42 no.4
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• pp.335-339
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• 2015

This paper reviews current status of weed science in Japanese regional agricultural systems based on the 54th Annual Meeting of the Weed Science Society of Japan. About 300 researchers from 5 countries including Korea participated in the Conference and presented 100 papers in research areas. This congress has an purpose to discuss new troubles, findings and results of weed science. Weed science faces big challenges such as increase in herbicide-resistant weeds, gene-flow from transgenic crops, and invasive weeds. Major research topics were invasive weeds and their ecology, allelopathy, weed management in paddy field, weed management in field crops, and herbicide resistance. Weed control and herbicide resistance management in paddy field were a main object of research. To prevent the increase of problematic weeds and to overcome food crisis, the importance of weed-related researches has been raised. Therefore it is expected that various weed management systems and control of herbicide resistant weeds should be studied continuously in the weed science.

• Korean Journal of Weed Science
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• v.32 no.3
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• pp.180-187
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• 2012

Panicum maximum, Panicum repens, Imperata cylindrica, Pennisetum polystachion and Cyperus rotundus are five rhizomatous grass weeds that exist and are problematic in the coconut lands of Sri Lanka. Rhizomatous weeds are the most difficult to control because of their vegetative reproduction by underground propagules. Therefore chemical and biological techniques have failed to control these weeds to acceptable levels. Experiments were conducted to investigate the impact of depth of burial, duration of sun drying or duration of air drying rhizomes of the selected weed species on germination. Depth of burial reduced germination of all species. Burying rhizomes at depths less than 10 cm inhibited germination of P. maximum and P. polystachion. Burying depths below 30~40 cm inhibited germination of all species. Sun drying or air drying rhizomes for durations less than 5 days inhibited germination of P. maximum and P. polystachion. Germinations of all species were inhibited by sun drying rhizomes for 15 days or air drying rhizomes for 20 days. Sun drying of rhizomes of all species for five days reduced the moisture content to a greater extent than air drying. The results indicated that burying rhizomes at the depthsbelow 30~40 cm, sun drying rhizomes for durations beyond 15 days or air drying rhizomes for durations beyond 20 days would be effective in controlling germination of these species. The investigations of the experiments also suggest that keeping rhizomes on the soil surface without burying, sun drying rhizomes or air drying rhizomes for durations of 5~15 days would produce weak plants.

• Weed & Turfgrass Science
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• v.6 no.2
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• pp.109-116
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• 2017

This study was carried out two surveys in 2015 to monitor weed occurrence and determine the most troublesome weeds in peach orchards of Korea. The first survey identified 56 taxa belonging to 23 families including 27 annuals, 11 biennials, and 18 perennials. Based on importance values, Conyza canadensis (5.12%), Plantago asiatica (4.17%), and Trifolium repens (3.86%) were the dominant weeds in the first survey (from April to June). Seventeen exotic weeds were identified in the first survey, including Conyza canadensis, Trifolium repens, and Chenopodium ficifolium. The second survey (from September to October) identified 42 weeds belonging to 19 families including 23 annuals, 5 biennials, and 14 perennials. According to importance values, Digitaria ciliaris (8.00%) was the most dominant weed, followed by Echinochloa utilis (6.61%) and Rorippa palustris (6.48%). There were 12 exotic weeds, including Taraxacum officinale, Rumex crispus, and Trifolium repens. Additionally, according to Braun-Blanquet's scale showed that the dominance value was level 1 (41.98% and 46.43%, respectively) in two surveys. Currently, 40% of the total surveyed peach orchards applied herbicides for weed control. These results could provide basic data to assist orchardists in selecting the most suitable weed management methods; thereby, reducing labor inputs and effectively lowering costs while improving fruit yields in peach orchards of Korea.

• Asian Journal of Turfgrass Science
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• v.20 no.2
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• pp.175-190
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• 2006

The term mycoherbicide started in 1970, but its interest heightened due to increase costs of chemical herbicides. A classical biocontrol agent is expected to become a permanent part of its new environment and do no harm to it. Contemporary biological control agent(BCA) must be produced by artificial culture and could be applied like chemical herbicides over weeds. BCA is different from the classical approach in that it released through natural spread. To date 26 species of fungi are used as classical BCA against 26 species of weeds in seven countries. There are a number of examples of pathogens attacking non-target plants. But through risk assessments which include understanding the taxonomy, biology and ecology, the target and non-target species, it will be safe to introduce of exotic pathogens to control weeds. But pathogens have not been successfully used in practice. Many mycoherbicides show potential in laboratories, but are ineffective in the field and not consistent from year to year or field to field. There is also a lack of understanding humidity, dew formation and temperature and their effects on suppression of weeds by plant pathogens. Potential pathogen must be selected as a BCA. Previous studies suggest that these pathogens must (1) produce abundant and durable inoculum in artifical culture, (2) be genetically stable and weed specific and (3) kill weeds in control. A granular preparation of mycoherbicide into sodium alginate is lighter than liquids and less bulky than organic matter. Gel forms have also been used.

• Korean Journal of Weed Science
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• v.1 no.1
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• pp.5-14
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• 1981

Weed is one of the problems in the crop land as well as in uncultivated land, raising the farm management costs. Therefore, the weed control is essential for effective agricultural management. The cost for weed control in Korea occupies on the average 27.6% of the total labor cost required. Agricultural policies since 1960 were transferring from yield increase due to land productivities to increase of income due to labor productivities. Therefore, the weed control by hand is also changed to weed control by chemicals. The weed control by chemicals has also brought about some side-effects and needs better, improved weed control methods. The present weed control situation and related problems were studied to present new approaches for agricultural development in the future. There were 458 species of weeds in 82 families which were growing in the crop land. The weeds to control, however, are 12 in paddy field and 9 in upland. So far weeds in paddy field are well under control, while weeds in upland are poorly controlled due to change in chemical efficiency and chemical damage in the upland. The administration, research and extension work for the efficient use of agricultural chemicals have been done by various institutions, such as Office of Rural Development, Office of Forestry, and chemical companies. The courses for agricultural chemicals were offered in the agricultural colleges. However, the efficiency of chemicals could not be maximized due to the poor relationships among related institutes. The newly established Agricultural Chemical Research Center at the Office of Rural Development and the Korean Weed Science Association are expected to contribute toward improving weed control in Korea. The Korean agriculture in the future will eventually be mechanized and the varieties resistant to high nitrogen application and to high plant density will be required for high yields. The rice will be transplanted earlier and the whole growing period will be extended. The application of organic matter will be increased for increasing soil fertility, and the use of agricultural chemicals will be continued. Under such a condition, the studies on the weed occurrence and its integrated control measures will be needed. Also weed controls in the newly exclaimed land, crop varieties, horticultural varieties, forage crops, and forests are also needed to study. Basic and practical researches for the weed control to improve the labor productivity will be also needed. In order to meet the all requirements for efficient weed control, weed control systems including all the academics, research and extension workers, administratives, farmers and companies should be established. Also securing researchers and education of personnels are pre-required and research funds for the chemical studies should be provided efficiently and timely.

• Korean Journal of Weed Science
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• v.2 no.1
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• pp.53-56
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• 1982

In order to establish the chemical weed control systems in orchard, efficacy of glyphosate and paraquat with oxyfluorfen, simazine and alachlor were evaluated in pear and peach orchards. Dominant weed species existed before glyphosate or paraquat application were Artemesia princeps, Calystegia japonica, Erigeron canadensis, and Lepidium apetalum, but Digitaria sanguinalis was one of the most dominant weeds throughout growing season of fruit trees. Gtyphosate at 120g/10a followed by oxyfluorfen at 04g/10a drastically reduced number of weeds and fresh weight of weeds and was found to be the most effective method for controlling weeds in orchard. Paraquat at 100g/10a followed by oxyfluorfen at 117g/10a and sequential application of glyphosate at 120g/10a also provided good weed control.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.357-357
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• 2017

The combined application of oil cake and rice bran into the soil surface was found useful for weed control in our previous pot study. The present study was undertaken to evaluate the performance of white clover (Trifolium repens L.) while incorporated in the paddy field and effects of combined fertilizer on weed control and rice yield. A plot was divided into two parts i.e. white clover incorporated and not incorporated. The nitrogen content of the incorporated white clover was $12.5gm^{-2}$. Chemical fertilizer and combined fertilizer plots were compared with non-fertilizer conditions. The mixed ratio of combined fertilizer was oil cake 1.35 and rice bran 1.0. Combined fertilizer was applied to the soil surface, and chemical fertilizer was mixed in the soil. Nitrogen application rate was $8gm^{-2}$ for any fertilizer. The weed numbers were significantly reduced in the white clover plot irrespective of application condition both at heading and harvest time. Also, weed control ability was improved by the use of combined fertilizer. In the not incorporated plot, the number of weeds was suppressed about 90% by applying combined fertilizer. The rice yield was markedly increased by the incorporation with white clover under all fertilization conditions. Contribution rates of increased rice yield by white clover and combined fertilizer were about 55% and about 25%, respectively. The rice yield was increased by the incorporation with white clover, and the number of weeds remarkably decreased as well. Also, these effects were improved due to combined application of oil cake and rice bran.

• Korean Journal of Weed Science
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• v.16 no.1
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• pp.28-35
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• 1996

Tetrapion(2,2,3,3-tetrafluoropropionate sodium) has commonly been used for reed(Phragmites communis Trin.) control in uncultivated areas, especially in Japan. As an attempt to establish the screening system for selective herbicide controlling reed, tetrapion was tested as a standard herbicide to various weeds and crops including rice in a greenhouse. Symptoms of yellowing, twisting, stunting, and necrosis were observed in the herbicide-treated plants. The herbicide caused a severe damage on all crops examined, except cotton. Both direct seeded and transplanted rice were also sensitive to the herbicide. Its herbicidal activity was generally higher on grass weeds than on broadleaf weeds. It had a higher herbicidal activity with preemergence treatment than with postemergence treatment. In addition, field and greenhouse experiments were conducted to examine the effect of the herbicide on reed control. Its effect varied with the soil type of the treated field and the growth stage of reed. A relatively high dosage of the herbicide was required to control reed. It had an almost same effect on fairygrass(Miscanthus sinensis Anderss) as on reed. However, reed grown in a greenhouse was effectively controlled by the herbicide, having more effect with preemergence treatment than with postemergence treatment as observed in other plants treated with the herbicide. In conclusion, tetrapion has a great potential as a standard herbicide during the herbicide screening for selective reed control.

• Korean Journal of Weed Science
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• v.15 no.2
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• pp.131-140
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• 1995

This experiment was conducted to test the effect on germination and seedling growth of major industrial crops and weed control potential using alfalfa plant. When dried alfalfa residues were mixed into vermiculite, germination, length of shoot and root of crops, such as Perilla frutescens, Sorghum nevosum, Platycodon grandiflorum and weeds, Digitaria saguinalis, Setaria viridis, Siegesbechia pubescens, Ammaranthus lividus, and Solanum nigrum, were significantly inhibited as the dried residue concentration increased. More than 10% concentration of the dired residue caused 80% germination and growth inhibition. The fresh alfalfa exudation also inhibited the germination and seedling growth of crop, barley, rye, alfalfa, and sesame, and weeds, Echinochloa crus-galli, Siegesbechia viridis, and Portulaca oleracea. The degree of inhibition showed the different response according to the fresh exudation concentration, types of crops and weeds. Generally, as the exudation concentration increased, the germination and seedling growth of crops and weeds inhibited. The exudation of dried residue also exhibited the strong inhibition effect on germination and seedling growth of crops, alfalfa, Platycodon grandiflorum, barley, sesame, rye and weeds, D. sanguinalis, S. pubescens, S. viridis, P. oleracea, E. crus-galli, At the 10% concentrations, S. pubescens, and P. oleracea were not germinated and showed only 15% germination in the S. viridis. From this study, would conclude that alfalfa plant contained water soluble phytotoxic substances which were inhibitory to weeds and crops. This results suggest that alfalfa had some possibility to control some weed species using toxic compounds like natural herbicide.

• Weed & Turfgrass Science
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• v.2 no.2
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• pp.111-121
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• 2013

Literatures were reviewed to understand the weeds occurring on the lawn and the effective control methods of them. Thirty-seven species of 16 families including three species of Cyperaceae for example Cyperus sanguinolentus, nine species of Poaceae including Digitalis ciliaris, Poa repens, etc., and 25 species of broad-leaved weeds such as Artemisia princeps, Draba nemorosa, Hydrocotyle sibthorpioides were occurred on the lawns. One hundred ninety-six weed species of 53 families were occurred on a tomb graveyard adjacent to the mountain. Therefore, it is possible to be infested by the weeds occurring on the graveyard on the golf course adjacent to the mountains. There are 67 items, 32 kinds of the soil treatment herbicides including dichlobenil GR, methiozolin EC, oxaziclomefone SC, imaxaquin GR et al, and 35 kinds of the foliar treatment herbicides including metamifop EC, bifenox flucetosulfuron WG, flazasulfuron WP, trifloxysulfuron-sodium WG et al. registered at the end of May 2012 for efficient management of the weeds occurring on the lawn. For effective management of the weeds, the herbicide can be generally applied twice a year on March to April and August to September for soil treatment and once a year on June to July for the foliage treatment.