• Weed & Turfgrass Science
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• v.7 no.1
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• pp.46-53
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• 2018

This study was conducted to establish standard fresh weight data about the minimum amount of occurred weeds at untreated paddy fields, upland fields and orchard fields (including non-cultivated land) in 10 areas. The amount of occurred weeds in each area was compared fresh weight with dry weight. The average percentage for ratio of dry weight to fresh weight in paddy fields was concluded to be 14.8% of Echinochola crus-galli, 12.5% of annual weeds (including Echinochola crus-galli), and 13.9% of perennial weeds. The average percentage for ratio of dry weight to fresh weight in upland fields was concluded to be 20.1% of annual weeds and in orchard fields was concluded to be 18.4% of annual and perennial weeds. According to the research, standard fresh weight about the minimum amount of occurred weeds at untreated paddy fields was proposed to $210g\;m^{-2}$ of Echinochola crus-galli, $400g\;m^{-2}$ of annual weeds (including Echinochola crus-galli), and $220g\;m^{-2}$ of perennial weeds. Standard fresh weight about the minimum amount of occurred weeds at untreated upland fields was proposed to $250g\;m^{-2}$ of annual weeds and at untreated orchard fields was proposed to $550g\;m^{-2}$ of annual and perennial weeds.

• Journal of Biosystems Engineering
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• v.27 no.2
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• pp.133-142
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• 2002

This is a fundamental study to develop a sensor to detect weeds in paddy field using machine vision adopted spectralphotometric technique in order to use the sensor to spread herbicide selectively. A set of spectral reflectance data was collected from dry and wet soil and leaves of rice and 6 kinds of weed to select desirable wavelengths to classify soil, rice and weeds. Stepwise variable selection method of discriminant analysis was applied to the data set and wavelengths of 680 and 802 m were selected to distinguish plants (including rice and weeds) from dry and wet soil, respectively. And wavelengths of 580 and 680 nm were selected to classify rice and weeds by the same method. Validity of the wavelengths to distinguish the plants from soil was tested by cross-validation test with built discriminant function to prove that all of soil and plants were classified correctly without any failure. Validity of the wavelengths for classification of rice and weeds was tested by the same method and the test resulted that 98% of rice and 83% of weeds were classified correctly. Feasibility of CCD color camera to detect weeds in paddy field was tested with the spectral reflectance data by the same statistical method as above. Central wavelengths of RGB frame of color camera were tried as tile effective wavelengths to distingush plants from soil and weeds from plants. The trial resulted that 100% and 94% of plants in dry soil and wet soil, respectively, were classified correctly by the central wavelength or R frame only, and 95% of rice and 85% of weeds were classified correctly by the central wavelengths of RGB frames. As a result, it was concluded that CCD color camera has good potential to be used to detect weeds in paddy field.

• Mycobiology
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• v.30 no.2
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• pp.96-101
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• 2002

Four pathogenic fungal isolates belonging to different genera including Alternaria, Fusarium and Curvularia were isolated from selected diseased weeds growing in the fields in Dakahalia district. The inoculum of these pathogenic fungi specific to weeds were cultured, standardized and formulated as alginate pellets containing mycelium plus culture filtrate. These mycoherbicides were evaluated for disease severity(DS). Maximum DS was obtained with the alginate pellets of mycelium filtrate Fusarium solani. Physiological changes of the treated weed were determined 5 aiid 10 days after treatments. As compared to the healthy weeds, all mycoherbicide formulations significantly decreased the amount of photosynthetic pigments and subsequently soluble and insoluble sugars in the infected weeds. The mycoherbicide formulation of F. solani had the greatest effect on lowering to the abovementioned amount in the leaves of Chenopodium murale. Generally, treatment of weed leaves with the specific mycoherbicide led to a highly significant increase in total phenol content when compared to the healthy control weed. C. murale infected with the mycoherbicide formulation of F. solani had higher levels of phenolic compounds than those other treated weeds particularly after 10 days of inoculation.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.15-18
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• 2003

Contemporary biological control system includes the use of fungi to control weeds in agricultural ecosystems and forests. Fungal pathogens of weeds that are highly virulent and specific to target weeds, and able to be produced massively by artificial culture could be applied like chemical herbicides over the weeds.(중략)

• The Plant Pathology Journal
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• v.39 no.4
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• pp.374-383
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• 2023

Capsicum annuum (CA) is grown outdoors across fields in Jeollabuk-do, South Korea. The weeds surrounding these fields were investigated regarding the infection of 11 viruses infecting CA during the year 2014-2018. In the reverse transcription polymerase chain reaction diagnosis, 546 out of 821 CA samples (66.5%) were infected by nine viruses, and 190 out of 918 weed samples (20.7%) were infected by eight viruses. Correlation analysis of the mutual influence of the viruses infecting CA and weeds during these 5 years showed that five viruses had significant positive correlations with the infection in both CA and weeds. Over the study period, the weeds infected by cucumber mosaic virus (CMV) in the previous year were positively correlated with the incidence of CMV infection in CA in the current year, although the correlation was lower for tomato spotted wilt virus (TSWV) compared to CMV. The CMV infection percent was 14.0% in summer annuals, 11.4% in perennials, and 7.8% in winter annuals. However, considering the overwintering period without CA, the infection percent was 5.2% higher in winter annuals and perennials than that in summer annuals, indicating that winter annual and perennial weeds served as the main habitats for insect vectors. The TSWV infection percent in weeds was 10.4% in summer annuals, 6.4% in winter annuals, and 6.2% in perennials. The weeds surrounding CA fields, acting as the intermediate hosts, were found to be the potent sources of infection, influencing the spread and diversity of CA-infecting viruses. The results of this study can contribute to prevent viral infection in agricultural fields.

• Journal of Environmental Science International
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• v.5 no.6
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• pp.801-812
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• 1996

We investigated concentrations of heavy metals(Cr, Cd, Zn, Fe, Pb, Cu, and Mnl and correlations between concentrations of heavy metals in the sediment, soil, weeds, and vegetables on the lower Nakdong river. Concentrations of heavy metals on the lower Milyang river was generally lower than those of other sampling area. In the soil, concentration of Pb is generally larger than that of other heavy metals. Generally, concentrations of heavy metals in the sediment show decreasing tendency 8s the sampling area moves toward downstream of the river, but those of in the soil and weeds show increasing tendency. There is no significant correlation between concentration of heavy metals in the soil-sediment, soil-vegetables, sediment-weeds, or vegetables-weeds. Only concentrations of Pb in the vegetables and those of in the weeds show very high correlation.

• Journal of Ginseng Research
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• v.23 no.3 s.55
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• pp.135-147
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• 1999

Nine herbicide products (fluazifop-p-butyl, clethodim, MCPA-sodium, 2,4-0 amine, chlorthal dimethyl, diquat, glyphosate, ethalfluralin and oryzalin) were evaluated for use on ginseng (Panax quinquefolius). Products varied in their ability to suppress weeds and certain materials were phytotoxic to ginseng in some trials. Chlorthal dimethyl (broadleaf weeds), MCPA-sodium (broadleaf weeds), fluazifop-p-butyl (grass weeds), and clethodim (grass weeds) were found to be effective as weed control agents and did not adversely affect ginseng growth. Other products tested were either not efficacious or were phytotoxic to ginseng in some trials. Weed populations were mainly introduced into the planting sites via the straw mulches used in ginseng cultivation.

• The Korean Journal of Pesticide Science
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• v.12 no.1
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• pp.1-8
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• 2008

The widespread and diverse sulfonylurea (SU) resistance problem has found in Korea, where one-shot-treatment herbicides such as pylazosulfuron/molinate and bensulfuron/molinate have been used continuously since 1989. The SU-resistant weeds of 7 annual weeds and 3 perennial weeds as of 2008 have confirmed in paddy fields in Korea. An effective management to SU-resistant weeds requires an integrated approach toward the weed control system, in particular, as to the drastic changes of herbicides development. Recent trend of new paddy herbicides in Japan has been developing to maximize the management of SU-resistant weeds. In the future, it is expected that the development of paddy herbicides in Korea is likely to be shifted toward the new "one-shot-treatment" included with herbicides of over 3-ways to maximize the control of resistant weeds. Bromobutide and carfentrazone are effective against sedges and broad-leaved weeds, respectively, and benzobicyclone and pyrimisulfam are effective against sedges and broad-leaved weeds.

• Journal of The Korean Society of Grassland and Forage Science
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• v.21 no.2
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• pp.103-108
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• 2001

This study was carried out to investigate the introduced route of exotic weeds and the effects of herbicide treatment. Herbicide trial was arranged as a completely randomized block design with treatment 1(\circled1 Dicamba $1\ell$/ha, \circled2 Mecoprop $5\ell$/ha, \circled3 Bentazone $3\ell$.ha, \circled4 Glyphosate $4\ell$/ha and \circled5 Pyrazosulfuron-ethyl 2kg/ha), and treatment 2(\circled1 Dicamba $2\ell$/ha, \circled2 Dicamba $4\ell$/ha, \circled3 Glyphosate $6\ell$/ha, \circled4 Glyphosate 4+Dicamba $1\ell$/ha and \circled5 Glyphosate 4+dicamba $2\ell$/ha) against 10 exotic weed species, and conducted in Suwon, Seosan and Yeongam from 1997 to 1999. Exotic weeds have been mostly introduced within imported cereals for concentrate feed or within seeds for forage production. Most of exotic weeds in forage crop field were controlled more than 95% by herbicide, but it was desirable that the control of exotic weeds was abreast of chemical and ecological method.

• Journal of Mechanical Science and Technology
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• v.20 no.10
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• pp.1576-1589
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• 2006

Most of surface water ways in Egypt suffer from the infestation of aquatic weeds especially submerged ones which cause lots of problems for the open channels and the water structures such as increasing water losses, obstructing the water flow, and reducing the efficiency of the water structures. Accurate simulation of the water flow behavior in such channels is very essential for water distribution decision makers. Artificial Neural Network (ANN) has been widely utilized in the past ten years in civil engineering applications for the simulation and prediction of the different physical phenomena and has proven its capabilities in the different fields. The present study aims towards introducing the use of ANN technique to model and predict the impact of the existence of submerged aquatic weeds on the hydraulic performance of open channels. Specifically the current paper investigates utilizing the ANN technique in developing a simulation and prediction model for the flow behavior in an open channel experiment that simulates the existence of submerged weeds as branched flexible elements. This experiment was considered as an example for implementing the same methodology and technique in a real open channel system. The results of current manuscript showed that ANN technique was very successful in simulating the flow behavior of the pre-mentioned open channel experiment with the existence of the submerged weeds. In addition, the developed ANN models were capable of predicting the open channel flow behavior in all the submerged weeds' cases that were considered in the ANN development process.