• Korean Journal of Weed Science
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• v.12 no.2
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• pp.144-157
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• 1992

The study was conducted to compare the interprete methods and examine the feasibility of mixture use of oxyfluorfen and bensulfuron in controlling principal Paddy weeds, annuals and perennials. Application ratio of both chemicals were obtained from the combinations of 5 levels(0, 5, 10, 15, 20 g ai/ha) of each chemicals, respectively. All the treatments were applied at 5 days after transplanting and water was maintained at 3.0cm in depth. Shoot fresh-weight of weeds was assessed at 35 days after treatments. Data obtained was analysed by Colby, Isobole, Calculus, Regression and EQM method, respectively. The results from the analysis of variance on the principal weeds treated with oxyfluorfen and bensulfuron showed significant interactions at 1% level on both Echinochloa crus-galli and Eleocharis Kuroguwai, and total species at 0.5% level on both Potamogeton distinctus and Cyperus serotinus, but non significant on Scirpus juncoides and Sagittaria pygmaea. Thereafter, the results of the models applied to Echinochloa crus-galli, Eleocharis kuroguwai and total species were as follows ; 1. The Colby method gave values nearly identical to regression estimate method (both multiplicative models) as provided by Akobundu et al. The Colby method and Regression method indicated synergistic toward Echinochloa curs-galli, and total species, but antagonistic toward Eleocharis kuroguwai. 2. The Isobole method shows synergism on Echinochloa crus-galli at $ID_{50}$, and total species at $ID_{60}$ on Eleochari kuroguwai. 3. The Calculus method gave positive signs for the first differentiation and negative signs for the second differentiation except for some rates on Echinochloa crus-galli and total species, but reverse on Eleocharis kuroguwai. These result does not agree with the observed values. 4. ${\theta}$ value from the EQM method was greater than one at all combinations. This result was quite different from those of other methods. 5. The various models did not show the same results, but mixture of oxyfluorfen and bensulfuron tend to have synergistic effect. Weeding effect also was high. Treatment in terms of two chemical combination was expected to reduce rates, and to enhence weeding efficacy compared with single treatment.

• Korean Journal of Weed Science
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• v.7 no.3
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• pp.329-336
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• 1987

Antagonistic interaction between glyphosate and some herbicides in effects of post-emergence application on cut grass and of pre-emergence application on some weed species including barnyardgrass was evaluated with pots in plastic house. By addition of oxyfluorfen to glyphosate, the weeding efficacy on cutgrass was visually evaluated as promotive in both weeding rate and efficacy. However, by alachlor, simazine, gluphosinate or quizalofop-ethyl showed delayed weeding rate, and by paraquat, the promotive in rate but lower in efficacy, respectively. Fresh weights of cutgrass at 30 days after the lower-rate application has generally indicated the lower weeding efficacy than that from glyphosate alone. Even at higher rate application, the addition of alachlor or simazine to glyphosate has still indicated the lower efficacies. As a result of interaction analysis by Colby method, no synergism was detected from any treatments, and the combinations of simazine or paraquat to glyphosate in lower mixing rate showed significant antagonism at 5% probability level of DMRT. On the annual weed species including barnyardgrass, the significant soil-residual weeding efficacies were recognized by addition of any rate of oxyfluorfen, alachlor, simazine and higher rate of quizalofop-ethyl to glyphosate, respectively.

• Korean Journal of Weed Science
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• v.17 no.3
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• pp.288-294
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• 1997

Field and pot expeiments were carried out to evaluate the interaction between quinclorac and bensulfuron-methyl on growth of the rice plants(Oryza sativa L. cv. Choocheongbyeo) at 20, 45, 65 days-old stages. Quinclorac and bensulfuron-methyl showed antagonistic interaction at both stages, which were detected by the Chisaka's method at isobles of 10% growth inhibition. The antagonism indices were -0.63 and -1.67 at 20 and 65 days-old seedling stages, respectively. Leaf-rolling of rice occurred when quinclorac was applied at 600g ai/ha or more at 20 days-old seedling stage, while it occured at the dose of 900g ai/ha at 65 days-old stage. Bensulfuron-methyl reduced plant height and dry weight as well as tiller production at both stages. Leaf-rolling of rice was reduced when mixture of quinclorac and bensulfuron-methyl was applied due to antagonism of the two herbicides. High temperatures increased the phytotoxicity of bensulfuron-methyl, while the phytotoxicity caused by quinclorac alone was not responsive to temperature. The antagonistic effect between quinclorac and bensulfuron-methyl increased at low temperature as tested by the Colby's method.

• Korean Journal of Weed Science
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• v.30 no.2
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• pp.143-152
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• 2010

Herbicidal characterisitcs of natural product chrysophanic acid were investigated in a greenhouse condition. At early- and middle-stage post-emergence treatments, several grasses and broadleaf weeds appeared to be very susceptible to chrysophanic acid. However, any significant herbicidal activity treated by pre-emergence did not occur at concentration ranges from 31.3 to 1,000 ug $mL^{-1}$. Herbicidal activity of chrysophanic acid estimated by visual injury for large crabgrass was much higher when applied at 7 to 14 days after seeding than at 21 and 28 days after seeding. By post-emergence treatment, chrysophanic acid caused very considerable phytotoxicity on several grasses and broadleaf crops. In herbicidal interaction experiments determined by Colby's method, the effect of chrysophanic acid and caryophyllene oxide tank-mixture showed very high synergistic activity. Although chrysophanic acid did not give any pre-emergence effect, herbicidal spectrum tended to be very wide and strong when treated by post-emergence. These results suggest that chrysophanic acid possesses a possible potential to develop as a natural herbicide.

• Korean Journal of Weed Science
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• v.13 no.1
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• pp.14-18
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• 1993

Greenhouse study was undertaken to find tank-mix feasibility of quinclorac with molinate and propanil, selective post-emergence herbicides in controlling barnyardgrass, for reducing the application rate of quinclorac. Following foliar application in combination of quinclorac at 0.038, 0.075, 0.150, and 0.300kg ai/ha with molinate at 0.190, 0.380, 0.750 and 1.500kg ai/ha, and propanil at 0.263, 0.525, 1.050, and 2.100kg ai/ha at 3.5-leaf stage of barnyardgrass, fresh weight and weeding efficacy and their interaction by Colby's efficacy method were evaluated. Percent inhibition of barnyardgrass growth by quinclorac, molinate and propanil at recommended rate were 78.1, 26.1, and 61.7%, respectively. The dose combination shown above 85% in weeding efficacy were from 0.300kg of quinclorac with 0.75kg of molinate and 0.150kg of quinclorac with all rates of propanil. Therefore, combination of quinclorac with molinate tended to additive interaction and that of quinclorac with propanil appeared partially synergistic interaction. Conclusively, for reducing the application rate of quinclorac, the combination of quinclorac with propanil was more synergistic than that of quinclorac with molinate.

• Korean Journal of Weed Science
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• v.3 no.2
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• pp.208-222
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• 1983

To control ideally the weeds in orchards and systematize the utility of herbicides, the mixing effect of oxyfluorfen and paraquat was evaluated. Combinations of oxyfluorfen with paraquat were increased the control efficacies at any treatment without giving damage to fruit trees and appeared a synergism. The control effects were reduced from 80-90% to 40-60% as the time advanced. However, the relative synergistic index was higher at 60 days after treatment in preemergence treatment and at 90 days after treatment in early and late postemergence treatment, respectively. Also the index was relatively higher at lower dosage of both herbicides.