• Korean Journal of Weed Science
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• v.16 no.1
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• pp.21-27
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• 1996

This experiment was conducted to find out an effective propagation method for reed(Phragmites communis Trin.), ensuring a continuous herbicide screening for reed control. Reed propagation methods were compared under a greenhouse condition using tour different materials; seeds, rhizomes, depressed stolons of P. japonica Steud., and stem cuttings. Although reed seeds were easy to harvest and store, their germination rate(${\leq}$5%) was very low and seedling growth from the seeds was slow. Rhizomes were difficult to harvest and their harvest time was limited from November to March. Furthermore, reed propagation using rhizomes had problems of a relatively low germination rate(46%), no uniformity in size and shape, individual differences at the early stage of growth, and difficulties in material storage. Rate of reed growth from rhizomes was higher in commercial soil mix(Boo Nong soil) than in sand or in sand+upland soil(1:1). Depressed stolons of P. japonica had a moderate germination rate(65%) and were relatively easy to harvest. However, their harvest time was limited only from August to September. Propagation method using stem cuttings had several advantages over the above methods using other materials. Reed plants could uniformly be propagated from the stem cuttings with a relatively high germination rate(75%). Stem cuttings of central nodes showed a higher germination rate compared to those of upper or lower nodes. Stem cuttings from the field should be used immediately after harvest, since their germination rate decreased rapidly when they were stored under a wet- or a dry-refrigerated condition. Furthermore, the germination of stem cuttings tended to decrease when they were collected from the field after August. This indicates that there is a limitation of harvest time for stem cuttings. However, a year-round propagation of reed using stem cuttings is possible if parent plants are grown in a greenhouse, and thus herbicide screening for reed control could continuously be performed.

• Korean Journal of Weed Science
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• v.14 no.2
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• pp.120-127
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• 1994

To establish an efficient herbicide screening method for purple nutsedge(Cyperus rotundus) control, its sprouting characteristics, tuber production and responses on several herbicides were investigated under greenhouse condition. The tubers stored at $4^{\circ}C$ after sterilization with the diluted prochloraz(Spotac) solution showed higher sprouting than the non-sterilized did. The harvested tubers were not dormant, and the sterilized tubers which stored at low temperature had a sprouting capability of about 80% after 6 months. If the fresh weight of purple nutsedge tubers was decreased to below 48%, they could not sprout. However, the tubers soaked in water and then stored at low temperature could sprout by 88% even 6 months later. Sprouting and initial growth of tuber were much better at $35^{\circ}C$-day/$25^{\circ}C$-night than at 30/$20^{\circ}C$ or 25/$15^{\circ}C$. The half-sected tubers, which were prepared by setting the intact tuber of above 1.2g latitudinally, were shown similar initial growth to the intact but those sected crucifically were not. These results suggest that the half-sected tuber itself can be used as a material on herbicide screening. About 1000 tubers could be harvested when 10 tubers planted in a pot($56{\times}35{\times}16cm$) filled with the artificial soil were cultivated in greenhouse of $35^{\circ}C$-day/$25^{\circ}C$-night for 3 months(April-July, 1993). Chlorimuron, Bentazon and Norflurazon were selected as the standards for the screening because of providing relatively effective control on purple nutsedge in both soil-surface and foliar spray treatment.

• Korean Journal of Environmental Agriculture
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• v.15 no.1
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• pp.116-127
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• 1996

Recent development in Japan on jumbo formulation of pesticides for paddy application by hand throw was reviewed. In addition, the diffusion of liquid formulations in water was examined to establish the research strategy for the jumbo formulation. Research on jumbo formulation in Japan has been focused on gas-generating formulations and self-emulsifiable formulations. Although continuous efforts to minimize the problem of pesticide deposit on the treated site have been made for the gas-generating formulations, much work is still needed to establish a generally acceptable formulation method and to commercialize a herbicide formulation. The self-emulsifiable jumbo formulations have recently been investigated. These formulations could simply be processed and showed relatively high biological efficacy. The emulsifiable concentrate was more diffusible than the suspension concentrate in water. The diffusion of the emulsifiable concentrate was not greatly disturbed by floating obstacles. And the diffusion rate was high when the specific grabity was lower than one.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.23 no.3
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• pp.5-11
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• 1978

Since 1970, herbicides have been widely used in the crop production, especially in paddy field in Korea. In 1978, both preemergence and postemergence type herbicides are applied in the approximately 70% of total paddy field and 15% of upland to control weeds. Most herbicides control annual weeds effectively, but perennials have been problems in the paddy field. Under upland conditions, effectiveness of herbicides varies depending on many environmental conditions (soil moisture, soil physical properties, temperature, etc.) as well as uniform application of appropriate amounts of herbicides. In Korea, many research works have been concentrated on the screening of new herbicides in terms of herbicide effectiveness and yield or phytotoxicity of crops, and especially on the paddy field. However, physiological aspects of herbicidal action in plant and interaction of herbicides with the environments have not been studied approximately. Therefore, researches on the uptake of herbicides and the influence of herbicides on the physiological phenomena such as photosynthesis, respiration, nutrient uptake etc., to control troublesome perennial weeds in the paddy field are needed in future. Also some researches are needed to improve effectiveness of herbicirdes under upland conditions.

• Korean Journal of Weed Science
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• v.6 no.2
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• pp.174-190
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• 1986

A series of laboratory and greenhouse experiments were conducted to find out the possibility of tissue culture and cell culture methods as a tool to study herbicidal behaviour and herbicide tolerance screening from 1985 to 1986 at the Yeongnam Crop Experiment Station. For dehulled-rice culture, pure agar medium was the most appropriate in rice growth campared to other media used for plant tissue culture method. All the media but the pure agar medium resulted in growth retardance by approximately 50% and this effect was more pronounced to root growth than shoot growth. Herbicidal phytotoxicity was enhanced under light condition for butachlor, 2.4-D, and propanil while this effect was reversed for DPX F-5384 and CGA 142464, respectively. And also, herbicides of butachlor, chlornitrofen, oxadiazon, and BAS-514 resulted in more phytotoxic effect when shoot and root of rice were exposed to herbicide than root exposure only while other used herbicides exhibited no significant difference between two exposure regimes. Similar response was obtained from Echinochloa crusgalli even though the degree of growth retardance was much greater. Particularly, butachlor, 2.4-D, chlornitrofen, oxadiaxon, pyrazolate and BAS-514 totally inhibited chlorophyll biosynthesis even at the single contact of root. Apparent cultivar differences to herbicide were observed at the young seedling culture method and dehulled rice cultivars were more tolerant in DPX F-5384, NC-311, pyrazolate and pyrazoxyfen, respectively. For derant than other types or rice cultivar in butachlor, pretilachlor, perfluidone and oxadiazon while Tongil-type rice cultivars were more tolerant in DPXF-5384, NC-311, Pyrazolate and Pyrazoxyfen, respectively. For dehulled rice culture, on the other hand, Japonica-type rice cultivar was less tolerant to herbicides of butachlor, propanil, chlornitrofen and oxadiazon that was reversed trend to young seedling culture test. Cultivar differences were also exhibited within same cultivar type. In general, relatively higher tolerant cultivars were Milyang 42, Cheongcheongbyeo, Samgangbyeo, Chilseoungbyeo for Tongil-type, Somjinbyeo for Japonica-type and IR50 for Indica-type, respectively. The response of callus growth showed similar to dehulled rice culture method in all herbicides regardless of property variables. However, concentration response was much sensitive in callus response. The concentration ranges of $10^{-9}M-10^(-8)M$ were appropriate to distinguish the difference between herbicides for E. crusgalli callus growth. Among used herbicides, BAS-514 was the most effective to E. crusgalli callus growth. Based on the above results, tissue culture method could be successfully used as a tool for studying herbicidal behaviour and tolerance screening to herbicide.

• The Korean Journal of Pesticide Science
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• v.10 no.2
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• pp.153-156
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• 2006

As an ongoing research program for the development of environmentally friendly new herbicide, several hydantoin derivatives 5a - 5i possessing amide subgroup were synthesized and shown to have interesting herbicidal activities exhibiting symptoms as Protoporphyrinogen IX oxidase inhibitor under postemergence upland greenhouse screening. Among derivatives tested, compound 5h showed superior herbicidal activity against upland problem weed, digitaria sanguinalis and aeschynomene indica to reference compound fluthiacet-methyl.

• Korean Journal of Weed Science
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• v.16 no.2
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• pp.140-149
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• 1996

Three hundred rice(Oryza sativa L.) cultivars were screened for tolerance to butachlor [N-(buthoxymethyl)-2-chloro-N-(2,6-diethylphenyl) acetamide], thiobencarb(S-[(4-chlorophenyl)methyl]diethylcarbamothioate), and simetryn [N,N-diethyl-6-(methylthio)-1,3,5-triazine-2,4-diamine]. The responses of the rice cultivars to herbicides differed depending upon the herbicides and their concentrations. New Sabarmati(BAS), Gora, PTB 18 were tolerant to butachlor, and Azucena, IR44707-31-1-3-2, ARC 7293 to thiobencarb, while Gora, ARC 7293, and Dudmona were tolerant to both herbicides. Response of rice to simetryn differed from its response to butachlor and thiobencarb. Inhibition of shoot growth and fresh weight increased as the temperature and herbicide concentration increased. There was a higher correlation among rice cultivars response to butachlor and thiobencarb in the greenhouse when laboratory studies were conducted at higher temperatures.

• The Korean Journal of Pesticide Science
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• v.12 no.2
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• pp.201-205
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• 2008

As an ongoing research program for the development of environmental friendly new soil-surface treatment herbicide, several tetrahydroindazole derivatives 6a - 6h possessing hydroxyalkyl subgroup were synthesized and shown to have interesting herbicidal activities exhibiting sumptoms as protoporphyrinogen IX oxidase inhibitor under pre-emergence upland greenhouse screening. Among derivatives tested, compound 6f showed superior herbicidal activity against problem weeds.

• Korean Journal of Weed Science
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• v.14 no.4
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• pp.252-257
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• 1994

The sprouting characteristics of Scirpus planiculmis and storage methods of corm for the herbicide screening were investigated under both laboratory and greenhouse conditions. Sprouting and elongation of S. planiculmis corms were continued during storage at low temperature ($5^{\circ}C$) and wet condition. However, sprouting of corm was failed when the surface water was removed from the corm, and elongation was reduced by the treatment of 0.5-1.0% sodium chloride(NaCl) solution. Alternate temperature was more effective on the sprouting of S. planiculmis corm than constant temperature. Optimum temperature for the sprouting of S. planiculmis corm was alternation between $25^{\circ}C$ to $35^{\circ}C$. Storage at $-20^{\circ}C$ for 10 min. or 14.7% dehydration made the corm of S. planiculmis to fail for sprouting. S. planiculmis corm was more tolerant to sodium chloride than Echinochloa crus-galli or Oryza sativa(Donginbyeo) seeds. Sprouting rate was decreased by cutting of the corm. Sprouting percent by vertical cuttings, horizontal cuttings, and vertical plus horizontal cuttings were 72, 56, and 28%, respectively.

• Weed & Turfgrass Science
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• v.7 no.1
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• pp.72-75
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• 2018

Balloon flower (Platycodon grandiflorum) is one of minor crops in Korea. Only four ACCase inhibiting herbicides are registered for P. grandiflorum and the farmers usually use general but unregistered herbicides which can cause critical phytotoxicity. So, this study was conducted to investigate effects of alachlor and pendimethalin on germination and early growth of P. grandiflorum. To evaluate the effect of alachlor and pendimethalin, two herbicides were treated to the seeds in petri-dish and soil. In the petri-dish, alachlor completely inhibited the germination as well as pendimethalin inhibited the germination slightly but not significantly. In case of soil application, alachlor inhibited germination and plant height of P. grandiflorum significantly as well as pendimethalin inhibited plant height and root length significantly. We showed the possibility of phytotoxicity of alachlor and pendimethalin to P. grandiflorum and strongly suggest that two herbicides should not be used to the cultivation of P. grandiflorum. Unregistered herbicides should not be used for weed management and additional researches for screening of safe herbicide to minor crops should be conducted as soon as possible.