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Herbicides for monochoria (Monochoria vaginalis) control in transplanted rice
- Zahra Hazrati, Bijan Yaghoubi, Pershang Hosseini, Bhagirath Singh Chauhan
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- Journal:
- Weed Technology / Volume 37 / Issue 6 / December 2023
- Published online by Cambridge University Press:
- 04 September 2023, pp. 598-605
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In Iran, monochoria is a noxious weed in fields of transplanted rice. Two field experiments were conducted to assess the efficacy of soil-applied and foliar-applied herbicides to control monochoria in transplanted rice. Prepackaged herbicides (triafamone plus ethoxysulfuron applied at 40 g ai ha−1, pyrazosulfuron-ethyl plus pretilachlor applied at 382.5 g ai ha−1, and pendimethalin plus clomazone applied at 1,200 g ai ha−1) reduced monochoria biomass by 100%, 100%, and 14%, respectively; and a single application of flucetosulfuron at 30 g ai ha−1, pendimethalin at 990 g ai ha−1, thiobencarb at 2,750 g ai ha−1, and pretilachlor at 1,000 g ai ha−1 reduced monochoria biomass by 100%, 99%, 75%, and 56%, respectively, compared with a nontreated control. Tank-mixed bensulfuron-methyl at 45 g ai ha−1 applied with pretilachlor, thiobencarb, or pendimethalin provided 100% control of monochoria. Rice height, and straw and grain yield were greater after herbicide treatments than those of the nontreated and hand-weeded controls, indicating the advantages of chemical control of monochoria over manual weeding. Full-season monochoria interference reduced rice grain yield by 32%. In the second study, the herbicides triafamone plus ethoxysulfuron, flucetosulfuron, 2,4-D at 1,080 g ai ha−1, dicamba plus 2,4-D at 928 g ai ha−1, bispyribac-sodium at 31.25 g ai ha−1, bentazon plus MCPA at 1,150 g ai ha−1, pyribenzoxim at 30 g ai ha−1, and propanil at 5,400 g ai ha−1 applied to foliage at 4- to 5-leaf seedlings of monochoria provided ≥97% control and prevented 100% of its regrowth, with the exception of propanil. This study shows that monochoria control can be achieved by using a variety of residual and foliar-applied herbicides with different mechanisms of action.
Integrated use of the stale seedbed technique with preemergence herbicides to control weedy rice in wet seeded rice
- Masilamany Dilipkumar, Mohd Shahril Shah Mohamad-Ghazali, Erwan Shah Shari, Ng Lee Chuen, Bhagirath Singh Chauhan, Tse Seng Chuah
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- Journal:
- Weed Technology / Volume 36 / Issue 3 / June 2022
- Published online by Cambridge University Press:
- 16 March 2022, pp. 373-378
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This study was undertaken to investigate the integration effects of pretilachlor, oxadiazon, and dimethenamid with or without glyphosate in a stale seedbed method to control weedy rice in wet-seeded rice. The study, conducted in 2018 and 2019, comprised two seedbed treatments in main plots, with and without glyphosate (850 g ae ha−1), and four subplot treatments: pretilachlor, oxadiazon, dimethenamid, and unsprayed check. Fifteen days after glyphosate spray, each subplot was treated with preemergence herbicides at 500 g ai ha−1 under standing water conditions (2 to 3 in.), and the water level was maintained for 7 d. Pregerminated rice seeds (var. MR297) were hand-broadcasted in the moist soil at 120 kg ha−1 seeding rate. In 2019, the density and dry weight of weedy rice were 30% and 118% higher Gthan those observed in 2018, respectively. A stale seedbed with glyphosate reduced weedy rice dry weight by 12% as compared to what was observed in a stale seedbed without glyphosate. Addition of oxadiazon and pretilachlor to the stale seedbed drastically reduced weedy rice dry weight by 70% to 88% and 53% to 60% in both years. Dimethenamid contributed to a significant reduction of weedy rice dry weight of 19% in 2019 only but failed to provide a positive economic return. Integration of pretilachlor and oxadiazon in a stale seedbed with glyphosate gave profitable returns of $84.00 to 311.4 ha−1 and $175.70 to 483.8 ha−1, respectively. Without the presence of glyphosate, pretilachlor and oxadiazon contributed a positive return of $318.90 and $469.40, respectively, in 2018, but the economic returns were negative in 2019. These results suggest that integration of pretilachlor or oxadiazon in a stale seedbed with glyphosate is more crucial when weedy rice infestation is high, but glyphosate can be excluded from the management regime when the weedy rice populations are low.
Performance of different herbicides on pondweed (Potamogeton nodosus) in rice
- Bijan Yaghoubi, Hashem Aminpanah, Bhagirath Singh Chauhan
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- Journal:
- Weed Technology / Volume 36 / Issue 2 / April 2022
- Published online by Cambridge University Press:
- 15 March 2022, pp. 270-275
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Pondweed is a rhizomatous perennial weed of aquatic habitats that recently adapted to rice ecosystems in northern Iran. Two field experiments were conducted at the Rice Research Institute of Iran to determine the impact of pondweed on rice yield and identify effective herbicides for pondweed control. The focus of the first study was to evaluate the herbicides commonly used in Iranian rice, including butachlor, pretilachlor, oxadiargyl, pendimethalin, thiobencarb, and bensulfuron-methyl. None of these herbicides effectively controlled pondweed, except bensulfuron, which reduced pondweed biomass by ≥95% and produced 26% higher rough rice grain yield than the nontreated plots. The second experiment evaluated the performance of acetolactate synthase–inhibiting herbicides on pondweed control, rough rice yield, and pondweed regrowth. Herbicide efficacy on pondweed varied from 36% to 100%. Five preemergence herbicides, bensulfuron at 45 g ai ha−1, flucetosulfuron at 30 g ai ha−1, triafamone plus ethoxysulfuron at 40 g ai ha−1, and metsulfuron-methyl at 15 g ai ha−1, provided ≥98% control of pondweed. Use of postemergence herbicides penoxsulam at 35 g ai ha−1, bispyribac-sodium at 30 g ai ha−1, and pyribenzoxim at 35 g ai ha−1 provided 36%, 89%, and 93% pondweed control, respectively. Rough rice yields ranged from 107% to 124% in herbicide-treated plots compared with the nontreated plots. Soil-applied herbicide treatments produced higher (≥119%) yield than the hand-weeded control or foliar-applied herbicides. Pondweed regrowth was affected by herbicides and was variable. Soil-applied residual herbicides metazosulfuron, flucetosulfuron, and metsulfuron provided complete control of pondweed and prevented regrowth. In contrast, pondweed regrowth in other soil- and foliar-applied herbicide treatments occurred, indicating their lesser translocation to underground vegetative rhizomes. This study shows that although most sulfonylurea herbicides can control pondweed effectively to achieve high rough rice yield, only a few soil-applied herbicides were able to prevent pondweed regrowth.
Rice safety and control of penoxsulam-resistant and -susceptible barnyardgrass (Echinochloa crus-galli) populations with soil-applied herbicides
- Tingting Liu, Jialin Yu, Jiapeng Fang, Liyao Dong
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- Journal:
- Weed Technology / Volume 35 / Issue 3 / June 2021
- Published online by Cambridge University Press:
- 03 March 2021, pp. 492-500
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Resistance to penoxsulam among barnyardgrass populations is prevalent in rice fields in China. Seeds of penoxsulam-resistant (AXXZ-2) and penoxsulam-susceptible (JLGY-3) barnyardgrass populations, as well as the seeds of two rice varieties, including Wuyungeng32 (WY) and Liangyou669 (LY), were planted in plastic pots and then treated with a rate titration of acetochlor, anilofos, butachlor, clomazone, oxadiazon, pendimethalin, pretilachlor, pyraclonil, or thiobencarb. The two barnyardgrass populations exhibited similar susceptibility to acetochlor, anilofos, butachlor, oxadiazon, pretilachlor, or pyraclonil. However, the susceptibility differed between the barnyardgrass populations in response to clomazone, pendimethalin, and thiobencarb. For AXXZ-2, herbicide rates that caused 50% reduction in shoot biomass from the nontreated control (GR50) were 179, >800, and 1,798 g ha−1 for clomazone, pendimethalin, and thiobencarb, respectively; whereas JLGY-3 GR50 values were 61, 166, and 552 g ha−1, respectively. Both rice varieties demonstrated excellent tolerance to acetochlor, butachlor, oxadiazon, pretilachlor, and thiobencarb. However, substantial rice damage was observed when anilofos and clomazone were used. Anilofos at 352 g ha−1 and clomazone at 448 g ha−1 reduced rice shoot biomass by 41% and 50% from the nontreated, respectively. Averaged across herbicide rates, clomazone use resulted in a reduction in rice shoot biomass from that of the nontreated control by 52% and 34% for WY and LY, respectively; and pendimethalin use resulted in a reduction in rice shoot biomass from the nontreated control by 25% and 9% for WY and LY, respectively.
Weeds and Weed Management of Rice in Karnataka State, India
- Adusumilli Narayana Rao, Suhas P. Wani, Mugalodi Ramesha, Jagdish K. Ladha
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- Weed Technology / Volume 29 / Issue 1 / March 2015
- Published online by Cambridge University Press:
- 20 January 2017, pp. 1-17
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Rice is one of the staple food crops of India, and Karnataka is one of the major rice-producing states. The primary method of rice establishment in Karnataka is transplanting, but farmers are opting to shift to direct-seeding of rice. Weed management is critical for realizing optimal yield of direct-seeded rice (DSR). The objective of this review was to synthesize the published literature on weeds and weed management in rice in Karnataka, identify improved weed-management technologies for delivery to farmers, and suggest research needs. Some 98 weed species are reported to be associated with rice in Karnataka. Weed control to date in Karnataka has mostly been based on herbicides. Hand-weeding was found to be effective in all methods of rice establishment. However, it is time-consuming, tedious, and costly because labor is becoming scarce and unavailable, and labor wages are higher. Several PRE and POST herbicides that were effective in other Asian countries were also found to be effective in managing weeds in rice established by different methods in Karnataka. Bensulfuron plus pretilachlor and pyrazosulfuron in aerobic rice and pendimethalin, thiobencarb, bispyribac-sodium, cyhalofop, fenoxaprop plus chlorimuron plus metsulfuron, and fenoxaprop plus ethoxysulfuron in dry-DSR were found effective in managing weeds. In wet-DSR, butachlor plus safener and pretilachlor plus safener were effective. Thiobencarb, pendimethalin, pretilachlor, azimsulfuron plus metsulfuron, bispyribac-sodium, butachlor, cinosulfuron, oxadiazon, and quinclorac were found promising for weed management in transplanted rice. Integration of herbicides with hand-weeding or intercultivation was found to be effective in rice established by different methods. Options that were found economical in managing weeds varied across the different rice-establishment methods. The need for developing location-specific, sustainable, integrated weed management and extension of available technologies for the farming community in Karnataka is emphasized.