• The Korean Journal of Pesticide Science
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• v.3 no.3
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• pp.1-5
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• 1999

Novel O-quinolinylamidoxime derivatives were prepared by replacement of the carboxylic group at the 8 position of quinclorac with various amidoximes. In the flooded paddy conditions, most of the compounds show good herbicidal activity at a rate of 1 kg/ha. Some of them showed excellent herbicidal activity at a rate of 60 g/ha against barnyardgrass (Echinochloa aryicola) with good selectivity on rice. Under the two-leaf stage of barnyardgrass, most of O-quinolinylamidoximes showed good herbicidal activity, expecially compound 3c which showed excellent herbicidal activity barnyardgrass at a rate of 125 g/ha with good rice seletivity.

• The Korean Journal of Pesticide Science
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• v.3 no.1
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• pp.96-101
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• 1999

3-Trifluoromethylpyrazoles and 4-benzenecarbinolpyrazoles were prepared by the new synthetic methodologies, and their herbicidal effects were tested (in vivo) in the upland conditions and in the flooded paddy conditions for the purpose of the development of new herbicides. In upland conditions, most of the pyrazoles showed weak herbicidal effects at 4 kg/ha dosage in the post-emergence test, while no herbicidal effects in the pre-emergence test. In the flooded paddy conditions, some of the pyrazoles showed good herbicidal effects at a rate of 4 kg/ha, especially, 3-trifluoromethyl-4-(4-methoxybenzoyl)pyrazole showed the best herbicidal activity with good selectivity between rice and weeds. But other derivatives substituted with electron-donating groups such as dior trimethoxy and sulfides, and 4-benzenecarbinolpyrazoles showed weak herbicidal effects.

• Asian Journal of Turfgrass Science
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• v.20 no.2
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• pp.157-165
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• 2006

This study was initiated to investigate herbicidal selectivity margin with annual bluegrass and bentgrass according to growth stages through herbicidal spectrum of bispyribac-sodium and therefore to examine application possibility to prevent annual bluegrass selectively. The herbicidal efncacy by pre-emergence application was generally low. But a high herbicidal efficacy was observed over 90% for Shehpherd's purse. Foliar treatment resulted in a higher herbicidal efficacy in all tested plants except dallisgrass, lovegrass, curled dock and bentgrass as compared with pre-emergence application. We found bispyribac-sodium could be used as a selective weeding chemical between annual bluegrass and bentgrass. In regard to dose-responses to the growth stage, annual bluegrass was more susceptible to bispyribac-sodium than bentgrass for the same dosage. Particularly, bispyribac-sodium application in inflorescence emergence stage showed a greater herbicidal selectivity margin of 6.8 times with annual bluegrass over creeping bentgrass after 28 days from the application. These data demonstrated that annual bluegrass was more sensitive to bispyribac-sodium over creeping bentgrass.

• The Korean Journal of Pesticide Science
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• v.3 no.2
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• pp.90-93
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• 1999

Several vinylsulfonylphenyl triketones and 2-alkoxy- and 2-(N,N-diethylamino) ethanesulfonylphenyl triketones have been synthesized, and their herbicidal activities in flooded paddy field were studied. Herbicidal effects of vinylsulfonyl triketones 6a-c were not satisfactory, whereas 2-alkoxyethanesulfonylphenyl triketones 7a and 7b showed good herbicidal activities without meaningful selectivity to rice.

• Korean Journal of Agricultural Science
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• v.38 no.2
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• pp.191-198
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• 2011

Herbicidal effects and crop selectivity of aqueous leaf extracts of sorghum (Sorghum bicolor L.) were evaluated against several weed species for developing sustainable weed management in organic farming. Aqueous sorghum leaf extracts were highly phytotoxic to different weed species. No broadleaf weeds were germinated in the concentration of 5 fold or higher concentrated sorghum leaf extracts and 90% of seed germination was inhibited within that range in grass species. Sorghum leaf extracts strongly inhibited the growth of different weeds by pre-emergence and foliar applications in greenhouse condition. Foliar application of sorghum leaf extracts had a higher inhibitory effect than the pre-emergence application. Broadleaf weed species were more susceptible than grasses to the application of sorghum leaf extract in foliar applications than grasses. Galium spurium, Erigeron candensis, and Rumex japonicus were completely killed at the highest concentrated sorghum leaf extract both in pre-emergence and foliar application. Most broadleaf weed species were inhibited more than 80% at pre-emergence application at 50 fold concentrated sorghum leaf extract. G. spurium, E. candensis, R. japonicus, Eclipta alba, Plantago asiatica and Portulaca oleraeea were most susceptible to sorghum leaf extract in foliar application. Growth of most broad leaf weed species was suppressed by greater than 90% at 50 fold concentrated sorghum leaf extract. Most crop species were tolerant to sorghum leaf extract but shoot growth was slightly reduced by the application of 40~50 fold concentrated extracts, Sorghum leaf extract may used to control weeds in organic fanning without affecting the growth of crop.

• The Korean Journal of Pesticide Science
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• v.3 no.3
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• pp.11-19
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• 1999

A some of synthesized 2-(4-(6-chloro-2-benzoxazolyloxy)phenoxy)-N-phenyl propionamide derivativesa substrates were found to selectivity significantly with both rice plant (Oryza sativa L.) and barnyard grass (Echinochloa crus-galli) for those her- bicidal activities with post emergence in up land. The selectivity of substrates against rice plant better than that of Fenoxaprop-ethyl. The structure activity relationship (SAR) n the selectivity of N-phenyl substituents were analyzed by the Free-Wilson and Hansch method. The SAR approach against barnyard grass is shown that the optimal ($({\pi})_{opt.}=1.60$) hydrophobicity and electron donating effects ($0<{\sigma}$ & 0$(ES)_{opt.}=0.87$) so that the herbicidal activity against rice plant can be decreased. The significance of these results on the selectivity between barnyard grass and rice plant is discussed. And it is assumed that the 2-ethoxy-3-methoxy-4-dimethylamino group substituent ($pI_{50}$=6.60, 1g/ha) is selected as the most highest herbicidal activity against barngard grass in green house.

• Applied Biological Chemistry
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• v.48 no.4
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• pp.394-399
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• 2005

The comparative molecular field analyses (CoMFA) models for the herbicidal activities against barnyardgrass (Echinochloa crus-galli) and rice plant (Orysa sativa L.) by the substituent (R) on the hexahydroisoindol-1-one ring in a series of new 2-(4-chloro-5-(2-chloroallyloxy)-2-fluorophenyl)-3-thioalkoxy-2,3,4,5,6,7-hexahydroisoindol-1-one derivatives were conducted and discussed for selectivity between both plants. The statistical results of the two best models (B2 & R7) showed the best predictability for the herbicidal activities based on the cross-validated value $q_2(r^2cv.=0.529{\sim}0.755)$ and none cross-validated value $({r^2}_{ncv.}=0.937{\sim}0.945)$, respectively. Based on the findings, the predictability and fitness of the model (B2) for barnyard grass was better than that of the model (R7) for rice plant. From the two models and contour maps, it is revealed that the novel selective character for herbicidal activity between the two plants depend on the electrostatic field and steric field for the substituent of ortho-positions on the S-phenyl group as R-substituent in hexahydroisoindol-1-one ring.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.4
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• pp.356-361
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• 2006

The present study was conducted to determine plant growth and physiological responses of corn, barnyardgrass, and soybean to ALA (5-aminolevulinic acid). ALA effect on early seedling growth of test plants was greatly concentration dependant, suggesting that it inhibits at higher concentrations. No significant difference in herbicidal activity of two types of ALA on plant height and weight of test plants was observed. Barnyardgrass was the most sensitive to ALA and followed by corn and soybean, indicating that both crop plants were less affected by ALA concentration as well as different growth stages than barnyardgrass. Greatly reduced chlorophyll contents from leaves of three plant species were observed with increasing of ALA concentration. Compared with untreated controls, higher amounts of three tetrapyrroles were detected from three crop plants, indicating more accumulation in ALA-treated plants. The differential selectivity among plant species would be explained with the differences in tetrapyrrole accumulating capabilities, the susceptibility of various greening groups of plant species to the accumulation of various tetrapyrroles, and their metabolism in various plant tissues. The results indicate that negative biological potential of ALA exhibited differently on plant species, and that the photodynamic herbicidal activity against susceptible plants highly correlated with the extent of tetrapyrrole accumulation by the species.

• The Korean Journal of Pesticide Science
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• v.3 no.3
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• pp.68-70
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• 1999

Hexahydro-1,2-bertzisoxazol-4-ols prepared from the diastereoselective reductions of 3-aryl-3a,4,5,6,7,7a-hexahydro-1,2-benzisoxazol-4-ones were reacted with benzyl chloride in the presence of sodium hydride to give new 4-benzyloxy-3a,4,5,6,7,7a-hexahydro-1,2-benzisoxazoles, which showed good herbicidal activity together with excellent selectivity on rice under submerged paddy conditions.

• Weed & Turfgrass Science
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• v.5 no.4
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• pp.191-195
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• 2016

Tefuryltrione is a new hydroxyphenylpyruvate dioxygenase (HPPD) inhibitor, which has been recently registered for the use for paddy rice, Korea. Dose-response studies were conducted to compare rice safety and weed control efficacy of tefuryltrione against Eleocharis kuroguwai. When rice and E. kuroguwai were applied at a range of doses of tefuryltrione, $GR_{90}$ values (the dose required to inhibit weed growth by 90%) of E. kuroguwai were $82.38-93.39g\;a.i.\;ha^{-1}$ in two independent experiments. The $GR_{10}$ values (the dose required to inhibit rice growth by 10%) of tefuryltrione for rice were $297.77-471.54g\;a.i.\;ha^{-1}$. As a result, the selectivity indices ($GR_{10}$ for $rice/GR_{90}$ for E. kuroguwai) of tefuryltrione were 3.19-5.72. Therefore, these results demonstrate that tefuryltrione has a relatively high selectivity between rice and E. kuroguwai with a high herbicidal activity against E. kuroguwai and a good rice safety.