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In order to improve both resistance to lepidopteran pests and resistance to the herbicide imazethapyr in mainstay japonica varieties of the Huang-Huai rice region, Sanming dominant genic male sterile (S-DGMS) rice was used as a platform to facilitate the pyramiding of functional genes and the replacement of the genomic background. Twelve novel lines were developed, each carrying a crystal toxin gene conferring resistance to lepidopteran pests and the ALS627N allele conferring resistance to herbicide imazethapyr in the background of a mainstay japonica variety. The genomic background of the 12 novel lines was examined using 48 specified molecular markers, and each line carried less than two polymorphic markers relative to the corresponding mainstay variety. All 12 lines displayed high resistance to lepidopteran pests and the herbicide imazethapyr. The major agronomic traits of the 12 lines showed no difference relative to the responding mainstay variety when sprayed with pesticide. The popularization of the 12 japonica lines could reduce the use of pesticides and provide highly efficient control of weeds and weedy rice in the future, thus promoting the development of japonica rice production. Therefore, S-DGMS rice could be a powerful tool for the genetic improvement of target traits in rice. [ABSTRACT FROM AUTHOR]

Unmanned aerial vehicles (UAVs) represent a cutting-edge technology that holds the promise of revolutionizing the conventional tasks carried out in the realm of agriculture. On a global scale, UAVs are gaining prominence for pesticide applications, particularly with a focus on utilizing low spray volumes. Nevertheless, there remains a notable gap in research concerning the impacts of employing low spray volumes on herbicide efficacy. Hence, multi-location field studies were conducted at Agricultural Research Station, Bhavanisagar and Wetland Station, Coimbatore, Tamil Nadu, India in 2022 to evaluate the impact of different spray volumes using UAV and Knapsack Manual Sprayer (KMS) on droplet deposition, droplet density, and weed control efficacy. The treatments included UAV sprays at 30 and 45 L ha-1, as well as KMS at 500 L ha-1, with a weedy check as a control. Bispyribac-sodium 10% SC was applied at a rate of 35 g a.i ha-1 during the 2-to 3-leaf stage of the crops. The results revealed that droplet deposition, area coverage, and volume median diameter were affected by sprayer type (UAV and KMS). However, the two spray volumes tested using the UAV method provided similar droplet parameters. The KMS system at 500 L ha-1 exhibited the highest droplet deposition, while the UAV system achieved better droplet distribution at a spray volume of 30 L ha-1. Remarkably, the UAV system at 30 L ha-1 demonstrated effective weed control, which was statistically comparable to the KMS system at 500 L ha-1. These findings emphasize that the UAV spraying system with a spray volume of 30 L ha-1, delivering effective weed control while utilizing less carrier volume compared to the manual knapsack spraying method. Thus, the UAV spray system has great potential as a viable alternative to manual knapsack spraying for herbicide application in direct-seeded rice. [ABSTRACT FROM AUTHOR]

The herbicide profoxydim, which is chiral in nature, is commonly used for weed control in rice. However, traditional achiral analysis treats profoxydim isomers as a single compound, providing only partial and inaccuracy information assuming identical behavior for the four isomers. To address this issue, a sensitive and straightforward chiral analytical method was developed using QuEChERS and chiral HPLC–MS/MS to determine the residues of all four stereoisomers of profoxydim in soil. The method was validated and found to have good accuracy and precision, with recoveries ranging from 88.27 to 104.93% for dry soil and from 98.25 to 106.53% for soaked soil, with RSD values lower than 11.14%. The limit of detection for the profoxydim isomers was 7.6 µg/kg, and the limit of quantification was 25.0 µg/kg. Furthermore, the proposed method was employed for the first time to investigate the individual degradation of novel isolated stereoisomers of profoxydim in soil and the kinetics and evolution of the generated degradation products (DPs). The degradation of the four stereoisomers followed first-order kinetics and was found to be stereoselective, with isomers 1 and 4 preferentially degrading with half-lives of 14.7 and 15.6 h respectively. The profoxydim enantiomers remained configurationally stable without any interconversion throughout the experiment. The findings of this study provide a robust scientific basis for improving profoxydim risk assessment and highlight the need to characterize chiral agrochemical isomers to better understand their environmental distribution and fate. [ABSTRACT FROM AUTHOR]

Weed management through herbicide is costing economically and environmentally. Developing of improved weed-suppressive rice genotypes is one of the ultimate goals of rice breeders for sustainable cultivation. In the current investigation, we evaluated the weed-suppressive potential of different rice genotypes and the genetic behind transmitting this ability to their progeny. To achieve this goal, a half diallel mating system was designed and conducted to generate F1 hybrids from six genotypes. Among these genotypes a previously developed allelopathic-resistant pre-breeding advanced lines, the F1 crosses along with their parents were cultivated under weed stress and normal field condition during the 2022 summer growing season. Several vegetative, allelopathic, yield and physio-biochemical traits were studied. The results indicate that the crosses AL1/Sakha Super 300 and AL2/Sakha Super 300 have the highest yield under weed stress condition. AL1, AL2 and Sakha Super 300 have the highest general combining ability for yield and allelopathic characters under weed stress. Furthermore, the cross AL2/Sakha Super 300 ranked the highest based on the stress tolerance indices. High positive correlation was detected between grain yield and the most studied physio-biochemical characteristics. This investigation provides evidence of the potential of enhancing the allelopathic activity of rice crop through precise selection of parental genotypes. [ABSTRACT FROM AUTHOR]

Fenoxaprop-P-ethyl (FE) can effectively control weeds in rice fields, but it has been found to cause phytotoxicity in rice. In this study, the phytotoxicity of FE was mitigated by perilla leaf essential oil (PEO) in rice seedlings. The injury recovery rates (IRRs) for shoot length and fresh weight treated with 800 mg/L of PEO were 101.51% and 99.05%, respectively. Moreover, the damage of s-metolachlor and pretilachlor was also alleviated when co-applied with 800 mg/L PEO; the IRR of s-metolachlor phytotoxicity was 26.07% and 27.34%, respectively, and the IRR of pretilachlor phytotoxicity was 127.27% and 124.39%, respectively. However, PEO had no significant effect on the phytotoxicity of pinoxaden, mesotrione, penoxsulam, mesosulfuron-methyl, and nicosulfuron. The results of GC–MS analysis showed that a total of 23 components were detected in PEO, among which linalool (36.49%), linalyl formate (26.96%), α-terpineol (10.63%), 2-hexanoylfuran (5.81%), geranyl acetate (4.13%), and neryl acetate (2.30%) were the primary components. Among them, 2-hexanoylfuran was the most effective component to alleviate FE damage, for which the IRR of shoot length and fresh weight was 73.17% and 73.02%, respectively, followed by the geranyl acetate, for which the IRR was 72.32% and 60.56%, respectively, and neryl acetate, for which the IRR was 65.28% and 58.11%, respectively. Furthermore, the application of 50 mg/L of 2-hexanofuran significantly improved the tolerance of shoot length and fresh weight to FE stress by factors of 5.32 and 5.35, respectively. This research demonstrates that PEO and 2-hexanoylfuran have the potential to serve as natural safeners to reduce phytotoxicity. [ABSTRACT FROM AUTHOR]

Identification and adoption of effective weed management practice play a fundamental role for a successful dry-seeded rice (DSR). This field experiment was designed to evaluate the impact of weed control options on weed management, productivity, nutrient uptake, and energetics in DSR. Echinochloa crus-galli (L.) Beauv. was the most dominant species followed by Leptochloa chinensis (L.) Nees. Among the weed control options, sequential applications of pendimethalin (1000 g a.i. ha−1) as pre-emergence and pre-mix combination of penoxsulam (1%) plus cyhalofop-butyl (5%) at 130 g a.i. ha−1 at 25 days after sowing (DAS) led to significant reduction in weed density (82.9%) and biomass (80.1%). This resulted in highest rice grain yield (3.92 t ha−1) and nutrient uptake, resulting in considerably higher energy productivity and lower specific energy. Brown manuring combined with application of metsulfuron methyl (10%) plus chlorimuron ethyl (10%) at 4 g a.i. ha−1 at 40 DAS was also effective in controlling weeds. Based on relative advantages of pendimethalin and penoxsulam plus cyhalofop-butyl in sequence over others, this may be recommended for weed control in DSR. [ABSTRACT FROM AUTHOR]

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Glyphosate IPA 240 g/L herbicide is known as one of the effective chemical solutions in weed control, especially in no-tillage systems. No-tillage systems offer advantages in upland rice cultivation by reducing soil damage and production costs. However, the main challenge in the application of no-tillage systems is the presence of pre-planting weeds that can compete with plants in the absorption of growth factors such as nutrients, light, and water. This experiment aims to test herbicide doses that effectively suppress weed growth and optimize the growth and yield of upland rice with the no-tillage system. The experiment was conducted from December 2023 to April 2024 at Ciparanje Farm, Faculty of Agriculture, Padjadjaran University, Jatinangor District, Sumedang Regency, West Java Province, Indonesia. The experiment used Randomized Block Design (RBD), consisting of 7 treatments, each repeated four times. The treatments consisted of 5 doses of glyphosate IPA 240 g/L herbicide 2.00, 3.00; 4.00, 5.00; 6.00 L/ha with no-tillage system; manual weeding; and control with perfect tillage system. Experimental results showed that glyphosate IPA 240 g/L herbicide at a dose of 3.00 - 6.00 L/ha with the no-tillage system can be used to replace the perfect tillage system because it can suppress the growth of broadleaf weeds, namely Ageratum conyzoides, Cleome rutidosperma, Mollugo pentaphylla and Synedrela nodiflora, and grass Digitaria ciliaris. No phytotoxicity symptoms were found, and had a favorable effect on rice plant growth regarding population size and tillers. The yield of rice plants with the highest milled dry grain yield was 4.45 t/ha. [ABSTRACT FROM AUTHOR]

A 2‐year field experiment was conducted in Daejeon, South Korea, to investigate changes in the growth parameters of rice plants during the growth and model the rice yield loss as affected by the competition with Leptochloa fusca, Bidens frondosa and Ammannia coccinea under transplanted rice cultivation. Compared with B. frondosa and A. coccinea, L. fusca significantly reduced the number of tillers at the early growth stage, resulting in more reduction in the number of panicles and other yield components such as the number of spikelets, ripened grain ratio and the ultimate rice yield at the later growth stage. Among the components, the panicle number was the most negatively and positively correlated with weed density and rice yield, respectively. Cousens' rectangular hyperbola model predicted that weed competitiveness value represented by parameter β was 0.0337 and 0.0572 for L. fusca, 0.0124 and 0.0165 for B. frondosa and 0.0059 to 0.0061 for A. coccinea in 20.8 and 15.2 hill m−2 rice densities, respectively, indicating the competition effect of L. fusca on rice yield was greater than that of B. frondosa and A. coccinea. Weed densities corresponding to a 50% reduction in the rice yield were 27 and 18 for L. fusca, 81 and 61 for B. frondosa and 169–164 for A. coccinea in 20.8 and 15.2 hill m−2 rice densities, respectively. Weeds are more competitive in low‐density rice plots, leading to greater yield loss. In addition, the economic thresholds (ET) are positively correlated with rice densities and negatively correlated with weed competitiveness. Although low‐density rice transplanting may offer economic benefits during cultivation, optimal rice density and weed control strategies are important for securing a high yield. Therefore, the model and findings could be applied to decision‐making systems in rice farming where weed interference is present. [ABSTRACT FROM AUTHOR]

A precision agriculture approach that uses drones for crop protection and variable rate application has become the main method of rice weed control, but it suffers from excessive spraying issues, which can pollute soil and water environments and harm ecosystems. This study proposes a method to generate variable spray prescription maps based on the actual distribution of weeds in rice fields and utilize DJI plant protection UAVs to perform automatic variable spraying operations according to the prescription maps, achieving precise pesticide application. We first construct the YOLOv8n DT model by transferring the "knowledge features" learned by the larger YOLOv8l model with strong feature extraction capabilities to the smaller YOLOv8n model through knowledge distillation. We use this model to identify weeds in the field and generate an actual distribution map of rice field weeds based on the recognition results. The number of weeds in each experimental plot is counted, and the specific amount of pesticide for each plot is determined based on the amount of weeds and the spraying strategy proposed in this study. Variable spray prescription maps are then generated accordingly. DJI plant protection UAVs are used to perform automatic variable spraying operations based on prescription maps. Water-sensitive papers are used to collect droplets during the automatic variable operation process of UAVs, and the variable spraying effect is evaluated through droplet analysis. YOLOv8n-DT improved the accuracy of the model by 3.1% while keeping the model parameters constant, and the accuracy of identifying weeds in rice fields reached 0.82, which is close to the accuracy of the teacher network. Compared to the traditional extensive spraying method, the approach in this study saves approximately 15.28% of herbicides. This study demonstrates a complete workflow from UAV image acquisition to the evaluation of the variable spraying effect of plant protection UAVs. The method proposed in this research may provide an effective solution to balance the use of chemical herbicides and protect ecological safety. [ABSTRACT FROM AUTHOR]

Deleterious rhizobacteria (DRB) is one of the rhizobacteria that can be used as a bioherbicide and can stimulate plant growth. The objectives that can be obtained from this study are to determine the potential of DRB on the growth of weeds Echinochloa crusgalli and Echinochloa colona on rice. Variables observed in this study were identification of secondary metabolites, measurement of weed sprouts, percentage effectiveness of bacterial isolates against weed seeds, normal sprouts, abnormal sprouts, fresh seeds that did not grow and dead seeds. The aim of this study is to explore biological agents that can be used to control the main weeds of rice crops. This candidate could be a recommendation for environmentally friendly controls. Exploration of the DRB group was obtained by collecting soil samples around the roots of rice crops. Then isolate it, identify as morphologically and physiologically, and test it in vitro studies. The results showed that DRB had the potential to control weed growth and could stimulate the growth of rice. The application of PFA and PFB isolates had a significant effect on inhibiting the length of weed roots and buds, the average percentage of control effectiveness > 80-90%. Novelty in this study could be found as candidate groups of DRB bacteria with specific locations to control the weed Echinochloa sp. on rice crops. For society, this research could be an alternative to reduce dependence on synthetic herbicides. DRB has the potential to be formulated into a bioherbicide to control weeds. [ABSTRACT FROM AUTHOR]

The article investigates the impact of response of direct seeded rice under different formulation of herbicides on yield and economics. The study examines the efficiency of the pre-emergence application of bensulfuron methyl + pretilachlor herbicide in weed control, grain and straw yield, weed dry matter production, net returns and returns per rupee invested, compared with post-emergence application of triafamone + ethoxysulfuron, fenoxaprop-p-ethyl and bispyribac sodium.

(1) Background: Cyperaceae weeds have become a major type of weed in local paddy fields in China. (2) Methods: We assessed the impact of environmental factors, including temperature, light, salinity, water stress and soil depth, on the germination and emergence of three dominant Cyperaceae weeds: Cyperus difformis L., C. iria L. and Fimbristylis littoralis Gaudich. Using the dish dipping method, the performances of the pre- and post-emergence herbicides commonly used in paddy fields on three Cyperaceae weeds were evaluated using the pot method. (3) Results: The seeds optimally germinated at 35 °C in constant conditions and 25 °C/40 °C in alternating conditions. The seeds of the three Cyperaceae weeds were sensitive to light and could not germinate under dark conditions. The germination rate of the three weeds decreased with the increase in the NaCl concentration and water potential; the three weeds could not germinate at a 320 mmol·L−1 NaCl concentration and −0.1 MPa water potential. When the pH levels were 4 to 9, the germination rates of the three weeds were all greater than 80%. The burial depths to inhibit 50% of the emergence of C. difformis, C. iria and F. littoralis were 0.27, 1.06 and 0.42 cm, respectively. The control efficacy of the pre-emergence herbicides of pretilachlor, butachlor and oxyfluorfen on the three weeds were all above 90% at the recommended dose in the field. Halosulfuron-methyl, florpyrauxifen-benzyl and bentazone could effectively control the three Cyperaceae weeds; their performances on the three weeds at the 3- to 4-leaf stage were all above 82%. (4) Conclusions: The three Cyperaceae weed seeds have a strong adaptability to temperature, water potential, salinity and soil depth, and these weeds are sensitive to most pre- and post-emergence herbicides. Therefore, taking Cyperaceae weed seeds into the deep soil layer by tillage or selecting appropriate herbicides according to their growth stages can effectively control Cyperaceae weeds in rice fields. [ABSTRACT FROM AUTHOR]

Pyraclonil is a new herbicide to control weeds in California water‐seeded rice (Oryza sativa L.). The objectives of this research were to evaluate weed control and rice response from pyraclonil applied alone at different timings and when applied in combinations with other herbicides. In one field study, pyaclonil was applied at 0.3 lbs a.i. ac−1 on pre‐seed bare ground, 1‐inch flood, 4‐inch flood and 3 days after flooding in water‐seeded rice. In another study, pyraclonil was applied at 0.3 lbs a.i. ac−1 at day of rice seeding and followed by various registered herbicides. Pyraclonil applications resulted in similar weed control across timings. Pyraclonil provided greater than 92% control of smallflower umbrella sedge (Cyperus difformis L.) and broadleaf weeds but less than 60% control of ricefield bulrush [Schoenoplectus mucronatus (L.) Palla] at 42 days after treatment. Watergrass (Echinochloa spp.) control was achieved with pyraclonil if applied before emergence. Early‐season rice injury from pyraclonil was observed; however, rice appeared uninjured later in the season. The addition of other herbicides after a pyraclonil application increased weed control levels across weed species and resulted in grain yields from 6,925 to 8,623 and 9,182 to 10,865 lbs ac−1 in 2019 and 2021, respectively. Pyraclonil provides early‐season weed control and, when incorporated with other herbicides, will be a useful herbicide in water‐seeded rice. Plain Language Summary: Pyraclonil is a new Group 14 herbicide available for early‐season weed control in California water‐seeded rice. We aimed to understand weed control and water‐seeded rice response from pyraclonil applied at different timings and in combination with currently registered herbicides. The application of pyraclonil at 0.3 lbs a.i. ac−1 at pre‐seed bare ground, 1‐inch flood, 4‐inch flood, and 3 days after flooding resulted in similar weed control. Control of smallflower umbrella sedge and broadleaf weeds was 92% or greater with pyraclonil. Watergrasses were controlled when applied before their emergence, and starting out with a field with no watergrass emergence is critical. Other herbicide combinations are necessary for season‐long weed control of ricefield bulrush and weedy grasses. Rice injury from pyraclonil was observed early in the season, but the rice appeared uninjured later in the season and rice yields resulted similar across treatments in both studies. [ABSTRACT FROM AUTHOR]

Recent research has demonstrated the ability of a fenclorim seed treatment to reduce rice (Oryza sativa L.) injury to acetochlor. However, all studies were conducted on silt loam soils and have not evaluated rice tolerance or weed control on clay soils. Experiments were initiated in 2021 and 2022 at the Northeast Research and Extension Center near Keiser, AR, to determine rice response and the effectiveness of delayed‐preemergence (DPRE)‐applied microencapsulated (ME) acetochlor (1.1, 1.7, and 2.3 lb ai acre−1) when applied to a clay soil with and without a fenclorim seed treatment at 0 or 2.5 lb ai 1000‐lb−1 of seed. Averaged over the fenclorim seed treatment, acetochlor at 1.1 and 1.7 lb ai acre−1 caused similar injury levels to rice; however, barnyardgrass [Echinochloa crus‐galli (L.) P. Beauv.] control increased at 1.7 lb ai acre−1, eliciting 19% injury to rice and 82% barnyardgrass control at 28 days after emergence (DAE). Palmer amaranth (Amaranthus palmeri S. Watson) control ranged from 82% to 93%. Additionally, fenclorim did not influence barnyardgrass or Palmer amaranth control, but it did reduce rice injury and increase shoot density, plant height, and rough rice grain yield. At 14 and 28 DAE, fenclorim at 2.5 lb ai 1000‐lb−1 of seed (averaged over acetochlor rates) reduced visible rice injury from 61% to 13% and 40% to 8%, respectively. Results from this study indicate ME acetochlor could be successfully applied to rice grown on a clay soil when a fenclorim seed treatment is used, providing producers a new site of action for use in U.S. rice production. Plain Language Summary: Rice producers in the Southern United States need new effective herbicides to control problematic weeds. Research has shown that acetochlor (Warrant herbicide), while not labeled, could be used to control barnyardgrass in rice, but crop tolerance is a concern. Fenclorim has been used as an herbicide safener seed treatment to reduce rice injury to microencapsulated acetochlor, but this research was conducted on medium textured soils (silt loam). Rice tolerance has not been demonstrated on clay soils and heavier soils tend to bind more herbicide, which would mean higher rates are needed for adequate control. We observed good crop tolerance with acetochlor at 1.7 lb ai/acre (4.5 pt/A warrant) and a fenclorim seed treatment. This rate also demonstrated up to 82% barnyardgrass and Palmer amaranth control 28 days after the rice emerged. If a microencapsulated acetochlor were to become labeled in rice, producers could use it as an alternative residual herbicide option within a program. [ABSTRACT FROM AUTHOR]

Biodecomposers are used as an alternative in pest and weed management by utilizing antagonistic microbes. This study aimed to identify the optimal treatment for suppressing weed growth and controlling the main rice pests, promoting environmentally friendly agricultural practices. Observations were made on three phases of rice growth on land that used biodecomposer and did not use biodecomposer. Weed sampling used a quadrant, which represents each treatment. All weeds were analyzed for density and summed dominance ratio. Pests were observed from the sweep net method. Pests were analyzed with the Shannon-Wiener diversity index (H’). Ten species of weeds are found; the most common and dominant was Cyperus difformis, while the least were Ipomoea aquatica and Ludwigia octovalvis. There were seven pest species; the most common was Nephothettix virescens, while the least was Valanga nigricornis. Using bio-decomposers combined with a two-row planting system was effective in suppressing the development of weeds and pests with a decreasing trend as the rice growing phase increases. Biodecomposers are environmentally friendly even though the process is slow, and have the potential to reduce weeds and pests. [ABSTRACT FROM AUTHOR]

Many plant species in nature exert significant allelopathic potential as part of the defense mechanism system, many among their secondary metabolites (allelochemicals), including mineral constituents, which are responsible for the suppression of weeds and enhancing crop yield when directly incorporated into paddy fields. Cissus sicyoides is considered a high-potential allelopathic plant because of its invasion in nature and detected allelochemicals from the plant parts in some studies. The objective of this research was to exploit the allelopathic properties of C.sicyoides against paddy weeds and some indicator plants under laboratory bioassays and greenhouse conditions. The results demonstrated that C. sicyoides had significant inhibition on E. crusgalli, tested plants, and other paddy weeds. In the laboratory conditions, the extracts from C.sicyoides leaves inhibited the growth of Echinochloa crus-galli by 54.3%. The powders from C.sicyoides leaves inhibited the emergence of paddy weeds by approximately 100.0%. In the greenhouse conditions, the powders from C.sicyoides leaves by adding after 3 and 13 days inhibited the growth of E. crus-galli and the emergence of paddy weeds by 64.4%. Remarkably, negligible harmful effects on rice growth were observed. The findings of the study may provide useful information for the exploitation of this plant species to effectively control weeds in the rice fields for sustainable agriculture production. [ABSTRACT FROM AUTHOR]

Pretilachlor is a chloroacetamide herbicide mainly used for weed and broadleaf weed control in rice, that is widely utilized in China. In order to detect the residue of pretilachlor in the environment and food, a highly sensitive and specific monoclonal antibody (mAb) against pretilachlor was prepared, and the half maximum inhibitory concentration (IC50) of the monoclonal antibody was validated to be 31.47 ± 2.35 μg/L. An indirect competitive ELISA (ic-ELISA) based on the antibody with a linear range of 6.25~100 μg/L was developed. The specificity of the antibody was explained by computer simulations and experimental validation. The mAb exhibited negligible cross-reactivity towards alachlor, acetochlor, propisochlor, butachlor, and metalaxyl, and the limits of detection (LOD) for pretilachlor in lake, rice, and soil samples were 4.83~5.23 μg/L. The recoveries of all samples were 78.3~91.3%. The reliability of the ic-ELISA method for residue detection of pretilachlor in the environment and grains was confirmed using high performance liquid chromatography. [ABSTRACT FROM AUTHOR]

SUMMARY: Bensulfuron‐methyl (BSM) is a widely used herbicide in rice cultivation, but the mechanisms underlying its efficient uptake in rice are poorly understood. In this study, a yeast library expressing 1385 rice transporters was employed to screen proteins sensitive to BSM. As a result, a cyclic nucleotide‐gated channel (CNGC) protein, OsCNGC12, was identified. By inactivating the OsCNGC12 function via gene editing, we developed BSM‐tolerant rice lines. Our results showed that the OsCNGC12 mutant rice not only reduced BSM uptake but also promoted Ca2+ influx in the roots, leading to enhanced non‐target‐site tolerance to BSM. OsCNGC12 is localized in the plasma membrane and is abundantly expressed in the root caps, root vascular bundles, stems, and leaves, indicating its vital role in the distribution of BSM in rice. The indispensability of His‐236, Gln‐240, and Arg‐268 in BSM perception in yeast was demonstrated through targeted mutagenesis of OsCNGC12. Furthermore, we developed a BSM seed coating agent for OsCNGC12 mutant rice, providing a simplified and cost‐effective means of weed control in direct‐seeded rice. Inclusion, this study showed that disruption of OsCNGC12 confers non‐target‐site tolerance to BSM in rice and has the potential for developing BSM‐resistant rice varieties. [ABSTRACT FROM AUTHOR]

BACKGROUND: Weeds grow aggressively in agricultural fields, leading to reduced crop yields and an inability to meet the growing demand for food. Herbicides are currently the most effective method for weed control. However, the overuse of herbicides has resulted in the evolution of resistance mutants and has caused environmental pollution. Therefore, new technologies are urgently required to address this global challenge. RESULTS: We report a copper‐benzene‐1,4‐dicarboxylate metal organic framework (Cu‐BDC MOF)‐functionalized carboxyl hollow mesoporous silica (HMS‐COOH) delivery system for the pH‐controlled release of the acetyl‐CoA carboxylase (ACCase)‐inhibiting herbicide quizalofop‐p‐ethyl (QE). The delivery system (QE@HMS@Cu‐BDC) enabled the efficient control of barnyard grasses that are susceptible and resistant to ACCase‐inhibiting herbicides, which showed 93.33% and 88.33% FW control efficacy at 67.5 g ha−1, respectively. With the lowest pH value (3), QE and copper ion were released slowly to total 70.30% and 78.55% levels (respectively) from QE@HMS@Cu‐BDC after 89 h. QE@HMS@Cu‐BDC showed better absorption, conduction, transportation and ACCase activity inhibition performance than that of QE emulsifiable concentrate (EC) in both susceptible and ACCase‐herbicide resistant barnyard grasses. In addition, with the safener effect of carrier HMS@Cu‐BDC and the aid of the safener fenchlorazole‐ethyl (FE), the application of QE@HMS@Cu‐BDC was shown to mitigate the damage caused by QE to rice plants. CONCLUSION: This work found that the new material HMS‐COOH@Cu‐BDC can be used to mitigate herbicide‐induced oxidative stress and improve rice plant safety. Futhermore, the QE@HMS‐COOH@Cu‐BDC constructed in this research might be used as an efficient nanopesticide formulation for weed controls in paddy rice fields. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

In the mid‐southern United States, rice (Oryza sativa L.) is flooded primarily to suppress weed germination and growth. Two experiments were conducted to determine whether herbicide performance in conventional or Clearfield rice weed control programs was affected by intermittent flooding. The effects of flooding and herbicide program on barnyardgrass [Echinochloa crus‐galli (L.) P. Beauv] control, rice grain yield, and water applied were investigated at the Delta Research and Extension Center in Stoneville, MS, on Sharkey clay (very fine, smectitic, thermic Chromic Epiaquert). For herbicides commonly applied in conventional (clomazone, quinclorac, pendimethalin, thiobencarb, fenoxaprop‐ethyl, cyhalofop‐butyl, and bisypriboac sodium) or Clearfield rice weed control programs (imazethapyr plus bispyribac‐sodium followed by imazethapyr, imazamox or bispyribac‐sodium), intermittent flooding had no adverse effect on barnyardgrass control relative to a continuous flood. Moreover, initiating irrigation when the perched water table drops to 8 inches below the soil surface had no effect on rice grain yield and reduced water applied by 51%. Mid‐southern US rice producers can capture the water‐saving benefits of intermittent flooding while having no adverse effects on herbicide activity or crop productivity in conventional and Clearfield systems. Core Ideas: Barnyardgrass control did not differ between intermittently and continuously flooded systems.Initiating irrigation when perched water table drops 8 inches below soil surface had no effect on rice grain yield.Intermittent flooding reduced water applied 51% compared to continuous flooding. [ABSTRACT FROM AUTHOR]

Deep-water (DW) management in rice fields is a promising technique for efficient control of paddy weeds with reduced herbicide use. Maintaining a water depth of 10–20 cm for several weeks can largely suppress the weed growth, though it also inhibits rice growth because the DW management is usually initiated immediately after transplanting. Improving the DW resistance of rice during the initial growth stage is essential to avoid suppressing growth. In this study, we demonstrate a large genetic variation in the above-ground biomass (AGB) after the end of DW management among 165 temperate japonica varieties developed in Japan. Because the AGB closely correlated with plant length (PL) and tiller number (TN) at the early growth stage, we analyzed genomic regions associated with PL and TN by conducting a genome-wide association study. For PL, a major peak was detected on chromosome 3 (qPL3), which includes a gene encoding gibberellin biosynthesis, OsGA20ox1. The rice varieties with increased PL had a higher expression level of OsGA20ox1 as reported previously. For TN, a major peak was detected on chromosome 4 (qTN4), which includes NAL1 gene associated with leaf morphological development and panicle number. Although there was less difference in the expression level of NAL1 between genotypes, our findings suggest that an amino acid substitution in the exon region is responsible for the phenotypic changes. We also found that the rice varieties having alternative alleles of qPL3 and qTN4 showed significantly higher AGB than the varieties with the reference alleles. Our results suggest that OsGA20ox1 and NAL1 are promising genes for improving DW resistance in rice. [ABSTRACT FROM AUTHOR]

Weed management in upland rice under subtropical climate with high rainfall is challenging. The diverse weed flora in upland rice ecosystem emerges in several flushes, necessitating sequential application of herbicides. A 4-year study conducted in Meghalaya (950 m above sea level), India indicated that sequential application of Cyhalofop butyl [2-{4-(4-cyano-2-fluorophenoxy) phenoxy} propionic acid, butyl ester (R)], a grass weed killer high efficacy low volume herbicide applied 80 g ha−1 at 25 days after sowing (DAS) and 2,4-D, a broadleaf weed killer herbicide applied 0.75 kg ha−1 at 35 DAS was effective for weed control and produced significantly higher grain yield (3572 kg ha−1) of rice with the highest weed control efficiencies than other treatments. Application of Pretilachlor followed by (fb) 2,4-D or Fenoxaprop-p-ethyl fb 2,4-D yielded significantly higher chlrophyll (chl) a, chl b and total leaf chl content compared with other herbicides at 90 DAS. The highest net energy (111,443 MJ ha−1), energy profitability and benefit:cost ratio was recorded with sequential application of Cyhalofop butyl and 2,4-D. Thus, sequential application of Cyhalofop butyl and 2,4-D could provide a sustainable weed management option in upland rice under high rainfall conditions in the Eastern Himalayas, India. [ABSTRACT FROM AUTHOR]

Propyrisulfuron is a novel pyrimidinylsulfonylurea herbicide with good activity for controlling annual weed in rice fields. To evaluate the economic performance of propyrisulfuron, a field study was conducted in 2021 and 2022 on a farm of the Jiangsu Academy of Agricultural Sciences, China. Eight different herbicide treatments were employed, including CB (cyhalofop butyl), Py (propyrisulfuron), CBPy (cyhalofop butyl plus propyrisulfuron), PrBe 3, PrBe 10, and PrBe 3+PrBe 10 (pretilachlor plus bensulfuron applied at different times [at 3 (PrBe 3) and 10 (PrBe 10) d] or sequentially, respectively), 2PrBe+PeCBBz (pretilachlor plus bensulfuron [applied sequentially] followed by penoxsulam plus cyhalofop butyl plus bentazone), 2PrBe+MeCBBz (pretilachlor plus bensulfuron [applied sequentially] followed by metamifop plus cyhalofop butyl plus bentazone), along with weedfree and nontreated weedy check treatments. Herbicide treatments did not cause visual phytotoxicity to rice, and bending and leaf rolling were not observed. Only the two propyrisulfuron treatments had temporary negative effects on rice height, but rice recovered quickly. Compared with the weed-free treatment, CBPy did not affect rice tiller number or dry matter accumulation. Compared with the nontreated weedy check, herbicide treatments reduced total weed density by 29.4% to 99.1% and dry biomass by 32.2% to 98.7%. The CBPy treatment provided the best weed control, reducing weed density and biomass by 96.7% and 95.9% in 2021 and 97.4% and 95.6% in 2022, respectively. Rice grain yield was not significantly different between CBPy and the weed-free treatment in either year. Economic analysis showed that CBPy provided the highest net profit, followed by that in 2PrBe+PeCBBz and 2PrBe+MeCBBz, with the lowest net profit in the nontreated weedy check. Thus, CBPy provides good weed control and could be promoted in mechanically transplanted rice fields in China. [ABSTRACT FROM AUTHOR]

Rice (Oryza sativa L) is a food crop commodity that has a major role in the development of agriculture and the main food of the Indonesian people. Rice is a rice-producing crop. Rice (Oryza sativa L) is a food crop commodity that has a major role in the development of agriculture and the main food of the Indonesian people. Rice yield loss due to weeds is estimated at 10 to 15%, even up to 86% without control. The purpose of the study was to determine the effect of herbicide dosage levels and obtain the best dose of the active ingredient Metsulfuron methyl on weed control and rice crop yield (Oryza sativa L.). The experimental method used was an experimental method using Group Randomized Design (RAK) consisting of 7 experimental units and repeated 4 times, so that 28 experimental plots were obtained. The experimental treatment was A (Metsulfuron methyl 15 g / ha, B (Metsulfuron methyl 20 g / ha), C (Metsulfuron methyl 25 g / ha), D (Metsulfuron methyl 30 g / ha), E (Metsulfuron methyl 35 g / ha), F (manual control) and G (control). The results showed that herbicides made from Metsulfuron methyl with doses of 15 g / ha – 35 g / ha had an influence on the population growth of rice weed species such as Cyperus iria, Fimbristylis miliacea and Leptochloa chinensis. Herbicide with active ingredient Metsulfuron methyl does not have a toxic effect on rice plants. Metsulfuron methyl with a treatment dose range from 15 g / ha – 35 g / ha has a significant effect on rice weed control when compared to control treatment. The dose of Metsulfuron methyl is significantly different when compared to all dose levels tested and is able to produce dry rice grain as much as 14.21 kg / plot or equivalent to 14.21 tons / hectare. [ABSTRACT FROM AUTHOR]

The characterization of the mechanisms conferring resistance to herbicides in weeds is essential for developing effective management programs. This study was focused on characterizing the resistance level and the main mechanisms that confer resistance to glyphosate in a resistant (R) Steinchisma laxum population collected in a Colombian rice field in 2020. The R population exhibited 11.2 times higher resistance compared to a susceptible (S) population. Non-target site resistance (NTSR) mechanisms that reduced absorption and impaired translocation and glyphosate metabolism were not involved in the resistance to glyphosate in the R population. Evaluating the target site resistance mechanisms by means of enzymatic activity assays and EPSPS (5-enolpyruvylshikimate-3-phosphate synthase) gene sequencing, the mutation Pro106Ser was found in R plants of S. laxum. These findings are crucial for managing the spread of S. laxum resistance in Colombia. To effectively control S. laxum in the future, it is imperative that farmers use herbicides with different mechanisms of action in addition to glyphosate and adopt Integrate Management Programs to control weeds in rice fields of the central valleys of Colombia. [ABSTRACT FROM AUTHOR]

The effect of spray volume on weed control in transplanted rice ecosystems using the Unmanned aerial vehicle (UAV) needs to be better understood for management in the advancements of UAV-based spraying technology. The present study aimed to find out the influence of varied spray volumes of 15 L/ha, 20 L/ha and 25 L/ha using the UAV and 500 L/ha using a Knapsack sprayer (KS) to compare the weed density, weed dry matter and weed control efficiency and yield in transplanted rice (Oryza sativa L.). Pre-emergence (PE) application of Pyrazosulfuron-ethyl at 25 g a.i./ha at three days after transplanting (DAT) and postemergence (PoE) application of Bis-pyribac sodium at 25 g a.i./ha at 25 DAT were used as herbicide treatments. The results revealed that varied spray volumes significantly influenced the weed density, dry matter, and weed control efficiency of the UAV and KS. Application of herbicides using KS (500 L/ha) and UAV (25 L/ha) had better control on the weeds by reducing weed density and dry matter at 20, 40, and 60 DAT, with no significant difference. Higher grain yield and straw yield were recorded in KS (500 L/ha) and UAV (25 L/ha), with no significant difference. However, applying 25 L/ha had better weed control efficiency and higher yield, possibly due to optimum deposition. Considering the low volume application of UAV (25 L/ha) as compared with KS (500 L/ha), it is better to go for the optimal application of 25 L/ha, which is an energy-efficient and cost-effective, laboursaving approach compared to KS. [ABSTRACT FROM AUTHOR]

Exploiting novel endogenous glyphosate‐tolerant alleles is highly desirable and has promising potential for weed control in rice breeding. Here, through fusions of different effective cytosine and adenine deaminases with nCas9‐NG, we engineered an effective surrogate two‐component composite base editing system, STCBE‐2, with improved C‐to‐T and A‐to‐G base editing efficiency and expanded the editing window. Furthermore, we targeted a rice endogenous OsEPSPS gene for artificial evolution through STCBE‐2‐mediated near‐saturated mutagenesis. After hygromycin and glyphosate selection, we identified a novel OsEPSPS allele with an Asp‐213‐Asn (D213N) mutation (OsEPSPS‐D213N) in the predicted glyphosate‐binding domain, which conferred rice plants reliable glyphosate tolerance and had not been reported or applied in rice breeding. Collectively, we developed a novel dual base editor which will be valuable for artificial evolution of important genes in crops. And the novel glyphosate‐tolerant rice germplasm generated in this study will benefit weeds management in rice paddy fields. [ABSTRACT FROM AUTHOR]

The widespread use of chemical herbicides has jeopardized concerns about food safety and ecological consequences. To address these issues and reduce reliance on chemical herbicides, a physical weed control device was developed for the tillering stage in paddy fields. This device features a biomimetic duckbill-like vibration chain that effectively controls weed outbreaks. The chain penetrates the soft surface soil of the paddy field under gravity and rapidly stirs the soil through vibration, leading to the detachment of the weed roots anchored in the surface layer. Simultaneously, the device avoids mechanical damage to rice seedlings rooted in deeper soil. This study aimed to investigate the effects of chain structural parameters (the number of chain rows, vibration amplitude, and length of chains) and operational parameters (vibration frequency and working velocity) on weed control efficiency and rice seedling damage. Through a central composite regression field test, the optimal device structure and operational parameters were determined. The optimization results demonstrated that a vibration amplitude of 78.8 mm, a chain length of 93.47 cm, and 3.4 rows of chains, along with a vibration frequency and working velocity ranging from 0.5 to 1.25 m/s, achieved an optimal weeding effect. Under the optimal parameter combination, field test results demonstrated that approximately 80% of the weeds in the field were effectively cleared. This indicates that the design of the biomimetic duckbill-like vibration chain weeding device exhibits a relatively superior weeding performance, offering a practical solution for the management of weeds in rice fields. [ABSTRACT FROM AUTHOR]

A field experiment was conducted during the late boro seasons (January-May) of 2018 and 2019 to assess the impact of herbicides on rice growth, yield and weed control in transplanted rice in the Agricultural Farm of Palli Siksha Bhavana (Institute of Agriculture), Visva-Bharati University, Sriniketan, West Bengal, India. There were eight different treatments consisting of pretilachlor 50 EC @ 500 g ha-1 at 3 DAT, pyrazosulfuron ethyl 10 WP @ 30 g ha-1 at 3 DAT, ethoxysulfuron 15 WDG @ 15 g ha-1 at 10 DAT, penoxsulam 21.7 SC @ 22.5 g ha-1 at 12 DAT, bispyribac-sodium 10 SC @ 25 g ha-1 at 15 DAT, hand weeding at 20 and 40 DAT, weed-free check and weedy check. Results from the pooled analysis of both the years revealed that pyrazosulfuron ethyl 30 g ha-1 and pretilachlor at 500 g ha-1 resulted in lower weed population and dry weight; higher plant height, number of tillers m-2, dry matter accumulation, leaf area index; grain and straw yield (5.98 and 7.81 t ha-1 and 5.81 and 7.62 t ha-1 respectively). The lowest weed index was registered by pyrazosulfuron ethyl 30 g ha-1 and pretilachlor at 500 g ha-1 and was superior to all other herbicidal treatments. Yield loss due to weeds infestation throughout the crop season was to the extent of 54.33%. Thus, pyrazosulfuron ethyl 30 g ha-1 and pretilachlor at 500 g ha-1 as pre-emergence may be recommended for effective weed control in transplanted late boro rice. [ABSTRACT FROM AUTHOR]

• Cassava leaf waste is not a problem, it is an economic resource. • Ethyl acetate extracts of cassava leaf inhibited weeds more than aerobic rice. • The extracts contained coniferol, transferuladehyde, luteolin, gigantol, and anemonin that inhibited bioassay species. Cassava, a major carbohydrate source for human consumption, generates significant residues during the harvesting process, including cassava (Manihot esculenta L.) leaves known to exhibit phytotoxicity. However, the water-soluble herbicidal compounds from cassava have not yet been identified. Therefore, this study aimed to identify the responsible phytotoxic compounds in cassava leaves. Phytochemical tests were conducted on aqueous cassava leaf extracts and solvents separated fractions, then phytotoxic compounds were analyzed by Liquid Chromatography Mass Spectrometry (LCMS) to determine their phytotoxic effects. Germination and growth on weeds of Eleusine indica, Ageratum conyzoides, Cyperus distans , and aerobic rice (Oryza sativa) were examined at 0.05% (w/v) in a laboratory assay. Results showed that the degree of phytotoxic activity of various fraction solvents can be listed in the order of decreasing inhibition: ethyl acetate>methanol>hexane>water. Five possible herbicidal compounds, including coniferol, transferuladehyde, luteolin, gigantol, and anemonin were identified from cassava leaf ethyl acetate extracts. These findings suggest that cassava leaves may be utilised as novel herbicidal agents for weed control in aerobic rice cultivation. [ABSTRACT FROM AUTHOR]

The present investigation determines the persistence of herbicides like butachlor and pretilachlor in Indian soil, and their impact on soil biological properties including microbial biomass carbon (MBC), total microbial population numbers, and enzyme activities. Butachlor was degraded faster in autumn rice soil (t1/2 of 10–13 days) than in winter rice soil (half-life of 16–18 days). The t1/2 of pretilachlor in winter rice was 12–16 days. Regardless of the seasons under cultivation, no pesticide residue was detected in rice at harvest. Herbicides induced an initial decline (0–14th days after application) in MBC (averages of 332.7–478.4 g g−1 dry soil in autumn rice and 299.6–444.3 g g−1 dry soil in winter rice), microbial populations (averages of 6.4 cfu g−1 in autumn rice and 4.6 cfu g−1 in winter rice), and phosphatase (averages of 242.6–269.3 μg p-nitrophenol g−1 dry soil h−1 in autumn rice and 188.2–212.2 μg p-nitrophenol g−1 dry soil h−1 in winter rice). The application of herbicides favored dehydrogenase (averages of 123.1–156.7 g TPF g−1 dry soil in autumn and 126.7–151.1 g TPF g−1 dry soil in winter) and urease activities (averages of 279.0–340.4 g NH4 g−1 soil 2 h−1 in autumn and 226.7–296.5 g NH4 g−1 soil 2 h−1 in winter) in rice soil at 0–14th DAA. The study suggests that applications of butachlor and pretilachlor at the rates of 1000 g ha−1 and 750 g ha−1, respectively, to control the weeds in the transplanted rice fields do not have any negative impact on the harvested rice and associated soil environment. [ABSTRACT FROM AUTHOR]

The application of novel bioorganic fertilizer (BIO) has been established as a weed biocontrol strategy, and reduce herbicides pollution and negatively effects on agricultural ecosystems. However, its long-term influences on soil bacterial communities are unknown. Here, 16 S rRNA sequencing to identify the changes that occur in soil bacterial community and enzyme under BIO treatments after five years in a field experiment. BIO application effectively controlled weeds, however no obvious differences between treatments were observed under BIO-50, BIO-100, BIO-200 and BIO-400 treatment. Anaeromyxobacter and Clostridium_ sensu_ stricto_1 were the two dominant genera among BIO-treated soil samples. The BIO-800 treatment had a slight influence on the species diversity index, which was more remarkable after five years. The seven significantly-different genera between BIO-800 treatment and untreated soils included C._sensu_stricto_1, Syntrophorhabdus, Candidatus_Koribacter, Rhodanobacter, Bryobacter, Haliangium, Anaeromyxobacter. In addition, BIO application had different effects on soil enzymatic activities and chemical properties. The extractable P and pH saliency correlated with Haliangium and C._Koribacter, and C._sensu_stricto_1 observably correlated with exchangeable K, hydrolytic N and organic matter. Taken together, our data suggest that BIO application effectively controlled weeds and a slight influence on soil bacterial communities and enzymes. These findings expand our knowledge of the application of BIO as widely used as a sustainable weed control in rice paddy. [ABSTRACT FROM AUTHOR]

Pretilachlor is one of the widely used chloroacetamide herbicides in Asian countries to control weeds in the rice field. The extensive use of herbicides has caused major concern among scientists throughout the world. Therefore, it is essential to develop an efficient method for the remediation of pretilachlor and its harmful by-products from contaminated surfaces. Mycoremediation is known to play a key role in the removal of various environmental contaminants. Hence, in the present study, strain AJN2 Aspergillus ficuum was isolated from a paddy field that was in continuous exposure to pretilachlor for over a decade. The degradation studies showed that the strain was efficiently able to degrade 73% of pretilachlor in an aqueous medium within 15 days of incubation and 70% of its major metabolite PME (2-methyl-6-ethylalanine). The GC/MS profile revealed the formation of aldehyde as the end product of degradation which was confirmed through the infrared fingerprint of the degradation sample. The ligninolytic enzyme activity studies showed that the lignin peroxidase enzyme system could be responsible for the degradation of pretilachlor and its major metabolite. The results highlight that the strain AJN2 A. ficuum could be a potential strain for the bioremediation of pretilachlor from the contaminated areas. [ABSTRACT FROM AUTHOR]

Existing rice inter-plant weed control devices have difficulty achieving inter-plant weed control in one pass. Due to the complex environment of paddy fields, these devices have a low weed removal rate and high seedling damage rate, making it difficult to ensure high-quality operation. This study innovatively designed a water jet-based rice inter-plant weed control device. Based on the mechanism of water jet erosion of soil, it can erode and excavate the soil layer on which weeds depend, achieving inter-plant weed control in paddy fields. The optimal range of structural parameters of the water jet angle and nozzle opening diameter was analyzed. The results showed that the optimal structural parameters of the device were a jet angle of 31° and a nozzle opening diameter of 4 mm, which can achieve the best operational performance. Based on virtual simulation experiments, single-factor and multi-factor orthogonal rotation combination experiments were carried out with weed removal rate as the test index and different operating speeds and nozzle outlet pressures as the test factors to optimize the water jet-based inter-plant weed control device. The experimental results showed that when the working parameters of the water jet-based inter-plant weed control device were a forward speed of 0.30 m∙s−1 and a nozzle outlet pressure of 1.50 MPa, the weed removal rate was the highest at 92.78%. Field validation experiments showed that the weed removal rate was 90.16% and the seedling damage rate was 1.80% under this operation condition, and the quality of the operation met the requirements of inter-plant weed control technology. This study provides a technical reference for promoting the development of inter-plant weed control technology in paddy fields. [ABSTRACT FROM AUTHOR]

Field experiments were conducted during Rabi 2018-19 (September to January) and Kharif 2019 (May to September). Medium duration rice cv. CO(R) 51 was used as a test variety at Tamil Nadu Agricultural University, Coimbatore, India to study the effect of Triafamone on broad spectrum weed control in transplanted rice. Triafamone was applied at two times. First set of treatments (30, 40,50 and 100 g/ha) applied two to three leaf stage of weeds and second set treatments imposed (30, 40,50 and 100 g/ha) at three days after transplanting of the rice crop. These treatments were compared with Pyrazosulfuron ethy 10% WP @ 15 g/ha, Pretilachlor 5% EC @ 750 g/ha, hand weeding @ 20 and 40 days after transplanting and unweeded control. The major grasses were Echinochloa crus-galli (L.) and E. colonum (L.) while the sedge weed included Cyperus nutans (L.). Among the broad leaved weeds Eclipta alba (L.) and Bergia ammanioides were the dominant species. In both the seasons of the study, lesser population of grass was recorded with the pre and early post emergence application of triafamone herbicide 40 g a.i. ha-1 (1.41 and 1.41 per m-2 at 28 and 42 DAA for both the seasons respectively) and it was closely followed by application of triafamone herbicide 50 g a.i. ha-1 and application of PE Pretilachlor at 0.75 kg a.i. ha-1 and EPOE Pyrazosulfuron ethyl at 15 g a.i. ha-1. The same trend was observed for broad leaved weeds and their weed dry weights. Application of triafamone herbicide at 40 g a.i. ha-1 as pre emergence and early post emergence application recorded highest weed control efficiency of 100, 97.7 and 99.6 % and 97.8% at 42 DAA during both years of experimentation and also resulted in higher grain yield (8052 and 8182 kg ha-1 during rabi 2018-19 and 9018, 9175 kg ha-1 during Kharif 2019). Further, it is noticed that, there was no residual toxicity of herbicide to the succeeding crops. Hence, application of Triafamone 40 g a.i. ha-1 either pre or early post emergence herbicide has higher productivity and no residues in transplanted rice ecosystem. [ABSTRACT FROM AUTHOR]

Agricultural weeder with nail assembly, popularly known as CRIJAF Nail Weeder, controls germinating and young weeds. It performs best at field capacity (FC) and has low draft (8-12 kg at FC) requirement. Its operation improves soil hydrothermal regimes and aeration (oxygen diffusion rate, 303 µg-2 O2 m-2 s-1). It has 5-6 detachable nails, each at 3 cm distance, and has option to attach one scrapper or one tine. Introducing a boat in place of its front wheels and addition of two conical rotors in the mainframe makes it suitable to control weeds in transplanted rice. It requires 12-18 man-days/ha for operation, controls 85-90% weeds, produced 33-40 q/ha jute fibre, 4.5-5 t/ha of upland and transplanted rice, 3.0-4.5 t/ha of wheat and 15 q/ha of mustard. More than 55,000 units have been distributed by the Department of Agriculture, Government of West Bengal. [ABSTRACT FROM AUTHOR]

Weedy biotypes of Oryza sativa L., (weedy rice) are a serious threat to rice production because of their flexibility in seed germination timing, variable growth forms, and high genetic diversity. Experiments were designed to determine the effects of storage conditions, osmotic stress, pH, salt stress, and burial depth on germination of weedy rice seeds in flooded or non-flooded conditions. Mature weedy rice seeds were gathered from rice fields in the different regions of Turkey. Three biotypes were selected and classified according to awn length; long awn, short awn and awnless. Seasonal germination patterns of weedy rice seeds in the laboratory after retrieval from various depths and timing were affected by burial depth, water regime, and exhumation timing across the treatments for all biotypes. The long and short awn biotypes had higher germination rates than the awnless biotype and did not have a seasonal germination pattern. Seed germination was initiated in the spring, peaked in summer and declined in the fall in flooded and non-flooded treatments for the awnless biotype. The most distinct differences in seedling emergence patterns were observed in awnless and long awn biotypes, and they emerged from 10 cm depth. Our results suggested that flooded conditions reduced the germination of weedy rice biotypes. Flooding rice paddies for a period of time after harvest may improve weedy rice control and decrease the weed population. In addition to deeper cultivation would be more effective in controlling all weedy biotypes since the majority of weed seedling emergence was from shallow depths. [ABSTRACT FROM AUTHOR]

Effective broad-spectrum herbicides are needed to address the issues of herbicide resistance and weed shifts in common cropping systems. A field experiment was conducted in 2016 and 2017 in West Bengal, India to compare the performance of three post-emergence herbicides (bispyribac-sodium; fenoxaprop-p-ethyl; penoxsulam) in monsoon rice (Oryza sativa L.) and their residual effects on succeeding rapeseed (Brassica rapa L.). Rice yield loss due to competition with Echinochloa colona (L.) Link, Leersia hexandra Sw., Cyperus iria L., Ludwigia parviflora L., and Monochoria vaginalis (Burm f.) C. Presl. Ex Kunth was 64% compared with weed-free control. Bispyribac-sodium 10% SC applied at 30 g a.i. ha−1 20 days after transplanting reduced weed density over the weedy control, ranging from 37% (M. vaginalis) to 87% (L. hexandra). Fenoxaprop-p-ethyl and penoxsulam applied, respectively, at 86 and 20 g a.i. ha−1 were effective in controlling grasses, but less effective against sedges and broadleaves. Bispyribac-sodium application resulted in highest rice yield (5.45 t ha−1), net return (Indian Rupees 42,677 ha−1), and benefit cost ratio (1.72). Bispyribac-sodium had neither adverse effect on soil microbes nor phytotoxic effect on rice and subsequent rapeseed. We recommend bispyribac-sodium for weed control in transplanted rice under rice-rapeseed system in eastern India. [ABSTRACT FROM AUTHOR]

Applications of very long-chained fatty acid elongase (VLCFA)-inhibiting herbicides are currently not labeled within U.S. rice (Oryza sativa L.) production but have been used in Asian rice production to suppress weedy rice and control other annual grasses and small-seeded broadleaves. Therefore, separate experiments were initiated in the fall of 2019 and 2020 to evaluate rice tolerance and weedy rice (O. sativa L.) control with acetochlor and pyroxasulfone in the following spring. A three-factor experiment within a randomized complete block design was implemented with the factors being (1) herbicide choice (acetochlor or pyroxasulfone), (2) a low or high herbicide rate (2100 and 4200 g ai ha-1, and at 237 and 475 g ai ha-1 acetochlor and pyroxasulfone, respectively), and (3) without or with a fenclorim seed treatment (2.5 g ai kg-1 of seed). Throughout the experiments, rice exhibited <10% injury with acetochlor. The fenclorim seed treatment reduced injury (averaged over herbicide choice and rate) from 28% to 21% 28 days after emergence of rice for both trial types. Fenclorim also improved rough-rice yield (averaged over herbicide choice and rate) by 12 and 18 percentage points for the two different studies. However, regardless of fenclorim, rice did not demonstrate <20% injury with pyroxasulfone. The fenclorim seed treatment or any interaction containing fenclorim did not influence weedy rice control, and weedy rice control with acetochlor ranged from 0% to 48%. Findings from this experiment demonstrate the effects of a fenclorim seed treatment for fall-applied acetochlor and pyroxasulfone and the efficacy of acetochlor and pyroxasulfone for controlling weedy rice. [ABSTRACT FROM AUTHOR]

National rice production continues to be increased to meet the needs of food security in Indonesia. But in reality, every rice cultivation always raises the problem of weed disturbances. One way to control weeds can be through waterlogging. Waterlogging can suppress weed growth and increase rice yields. This study was conducted from August 2019-January 2020 at greenhouse conditions, Faulty of Agriculture, Universitas PGRI Yogyakarta. The study aimed at knowing the waterlogging period to minimize weed competition and increase the rice yield. This study was arranged in a completely randomized design (CRD) factorial with three replications. The first factor was the waterlogging period, which consisted of three levels : without waterlogging, 1-15 days after planting (DAP) and 1-30 DAP. The second factor was soil types, which consisted of four kinds : latosol, coastal sandy, volcanic and regosol soil. The weed observation was carried out at 60 DAP, and the rice was done at 104 DAP. The results showed that waterlogging could minimize weed competition in rice fields. Furthermore, waterlogging period of 1-30 DAP could inhibit the weed dry weight (WDW) and increase the leaf area index (LAI), shoot : root ratio (SRR), grain dry weight (GDW) and harvest index (HI) in different soil types. Waterlogging period of 1-30 DAP gave the highest GDW in latosol (7.5 t/ha), then decreased in volcanic (6.0 t/ha), regosol (5.9 t/ha) and the lowest in coastal sandy (4.8 t/ha). The research findings showed that waterlogging period of 1-30 DAP could minimize the weed competition and increase the rice yield. Thus, it was highly recommended to be practised as cultural weed control in rice cultivation. In future research, weed types that are tolerant to waterlogging treatment need to be combined with weeding treatment. [ABSTRACT FROM AUTHOR]

BACKGROUND: Weeds are a significant barrier to rice production in California, exacerbated by lack of chemical control options and herbicide‐resistance in persistent aquaphilic species. Oxyfluorfen‐tolerant rice, created at the Rice Experiment Station (RES) in Biggs, California, was developed to provide an agronomic program for managing problematic grass and sedge rice‐weeds including Oryza sativa f. spontanea Roshev. (weedy 'red' rice). Hand‐pulling is the most common removal method for O. sativa spontanea because there are no herbicides registered for this pest in California. Oxyfluorfen was used in combination with oxyfluorfen‐tolerant rice in 2019 and 2021 field studies to evaluate rice injury and weed control efficacy on prevalent rice‐weed species. Additional studies were conducted in 2021 on University of California Davis campus to determine pre‐emergent oxyfluorfen efficacy on four California O. sativa spontanea accessions. RESULTS: Fields studies indicated minimal crop injury in the first 28 days after seeding (DAS), but no observable injury at 60 DAS in both years. Weed control with oxyfluorfen alone was 87% or greater for all weeds rated with the exception of Schoenoplectus mucronatus (L.) Palla (ricefield bulrush), and Leptochloa fascicularis (Lam.) A. Gray (bearded sprangletop) in both years. All O. sativa spontanea exposed to soil‐applied oxyfluorfen successfully emerged through the soil surface, but became completely necrotic 28 days after flooding. CONCLUSION: Oxyfluorfen‐tolerant rice system was demonstrated to be a viable management strategy for California rice growers who struggle with grass‐ and sedge‐weed control as well as provide a novel herbicide option for California O. sativa spontanea management. © 2022 University of California, Davis. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Weed control is needed to avoid competition in early rice growth. A weed control method is waterlogging. The study aimed to investigate the effect of waterlogging on weed seed germination and growth in lowland rice. This research was arranged in a completely randomized design (CRD) factorial and three replications. The first factor was waterlogging, which consisted of three levels: without waterlogging, 1-15 days after planting (DAP), and 1-30 DAP. The second factor was focused on two different soil types: latosol soil (LS) and regosol soil (RS). The results showed that waterlogging could inhibit seed germination of weed in RS but not in LS. In this study, waterlogging of 1-30 DAP inhibited weed dry weight higher than 1-15 DAP in both soil types. Waterlogging of 1-30 DAP decreased the weed dry weight by 87.2% in LS and 97.3% in RS than without waterlogging. Waterlogging could change the summed dominance ratio (SDR) of weed species. The research findings show that the waterlogging period of 1-30 DAP effectively inhibits the weed seed germination and growth in RS, but in LS could extend. We recommend that waterlogging period of 1-30 DAP can be applied for weed control in lowland rice. [ABSTRACT FROM AUTHOR]

Bipolaris eleusines was mixed with herbicides to improve the control of barnyardgrass (Echinochloa crus-galli), a noxious weed in rice fields. The compatibility of B. eleusines with herbicides was evaluated for toxic effects on spore germination and mycelium growth in vitro tests, and varied effects were observed with different chemical products. Briefly, 25 g/L penoxsulam OD plus 10% bensulfuron-methyl WP were much more compatible with B. eleusines, and there was no inhibition of spore germination but the promotion of mycelium growth of B. eleusines at all treatment rates. Under greenhouse conditions, the coefficient of the specificity of B. eleusines conidial agent was determined as 3.91, closer to the herbicidal control of 2.89, showing it is highly specific between rice and barnyardgrass. Field experiments in 2011 and 2012 showed that B. eleusines conidial agent displayed good activity on barnyardgrass, monochoria [Monochoria vaginalis (Burm.f.) Presl. Ex Kunth.], and small-flower umbrella sedge (Cyperus difformis L.) and had no negative impact on the rice plant. It also reduced the loss of rice yield when compared with the non-treated control and could make this pathogen a conidial agent for commercial bioherbicidal development in the future. [ABSTRACT FROM AUTHOR]