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This study is to understand the fate and ecological consequences of pyroxasulfone in aridisols of Punjab, a detailed dissipation study in soil, its influence on soil enzymes, microbial count and succeeding crops was evaluated. Half-lives (DT50) increased with an increase in the application rate of pyroxasulfone. Dissipation of pyroxasulfone decreased with increase in organic matter content of soil and was slower in clay loam soil (DT50 12.50 to 24.89) followed by sandy loam (DT50 8.91 to 17.78) and loamy sand soil (DT50 6.45 to 14.89). Faster dissipation was observed under submerged conditions (DT50 2.9 to 20.99 days) than under field capacity conditions (DT50 6.45 to 24.89 days). Dissipation increased with increase in temperature with DT50 varying from 6.46 to 24.88, 4.87 to 22.89 and 2.97 to 20.99 days at 25 ± 2, 35 ± 2 and 45 ± 2 °C, respectively. Dissipation was slower under sterile conditions and about 23.87- to 33.74-fold increase in DT50 was observed under sterile conditions as compared to non-sterile conditions. The application of pyroxasulfone showed short-lived transitory effect on dehydrogenase, alkaline phosphatase and soil microbial activity while herbicide has non-significant effect on soil urease activity. PCA suggested that dehydrogenase and bacteria were most sensitive among enzymatic and microbial activities. In efficacy study, pyroxasulfone effectively controlled Phalaris minor germination, with higher efficacy in loamy sand soil (GR50 2.46 µg mL−1) as compared to clay loam soil (GR50 5.19 µg mL−1). [ABSTRACT FROM AUTHOR]

Field experiments were carried out during Rabi season 2020–21 and 2021–22 at Agronomy Research Farm, CCS HAU, Hisar, for the management of multiple herbicide-resistant Phalaris minor in wheat. Experiment was performed using randomized block design and replicated thrice with a total number of 15 treatment consisting of different combination of pre (PRE) and post-emergence (POST) herbicides. Herbicides selected in this study have different modes of action, i.e. clodinafop and pinoxaden are acetyl-CoA carboxylase (ACCase) inhibitors, sulfosulfuron, mesosulfuron, iodosulfuron and metsulfuron belongs to acetolactate synthase (ALS)/Acetohydroxy acid synthase (AHS) inhibitor group, pendimethalin and pyraxosulfone inhibits the microtubule assembly and long chain fatty acids synthesis, respectively, while metribuzin is Photosystem-II (PS-II) inhibitor and flumioxazin is from protoporphyrinogen oxidase (PPO) inhibitor group. Among different treatments, application of flumioxazin + pendimethalin fb clodinafop propargyl + metribuzin (RM) resulted in significantly lower density and dry weight of P. minor and broadleaved weeds and maximum weed control efficiency at 60 DAS. It was statistically comparable to application of flumioxazin, flumioxazin + pendimethalin, pyroxasulfone + pendimethalin fb mesosulfuron + iodosulfuron (RM), or pinoxaden + metsulfuron (TM) or clodinafop propargyl + metribuzin. Sequential application of pyroxasulfone + pendimethalin (TM) fb mesosulfuron + iodosulfuron (RM) resulted in significantly higher grain yield (5847 and 5369 kg/ha) when compared to rest of the treatments. It was statistically comparable to PRE pyroxasulfone + pendimethalin (TM) fb POST pinoxaden + metsulfuron (TM) or clodinafop propargyl + metribuzin (RM). In conclusion, pre-emergence application of pyroxasulfone + pendimethalin (TM) followed by post-emergence application of either mesosulfuron + iodosulfuron (RM), pinoxaden + metsulfuron (TM) or clodinafop propargyl + metribuzin resulted in better control of resistant P. minor and broadleaved weeds along with higher grain yield. [ABSTRACT FROM AUTHOR]

Background: The seedling stage is the most vulnerable period of growth and development for annual weeds and an important target for weed management operations. To address this, several weed emergence models have been developed, but none are commercially available. Therefore, this study aims to develop a web application that implements predictive weed emergence models for eight different weed species, utilizing weather data sourced from public weather stations. Results: Lolium rigidum Gaudin presented a mean root mean squared error (RMSE) value of 8.9, achieving an RMSE value below 15 (success rate) in 84.5% of cases. This result may be attributed to the use of a water potential base, set at −0.4 MPa, to evaluate water availability. Centaurea diluta Aiton achieved an RMSE value below 15 in all situations, with an average value of 9.0. This weed showed higher accuracy at southern sites than northern sites. Conversely, Avena sterilis ssp. ludoviciana (Durieu) Gillet & Magne achieved higher precision at northern sites where no dry periods occurred. The newly developed model for Bromus diandrus Roth. achieved an average RMSE value of 7.7 and a 100% success rate. Papaver rhoeas L. and the three Phalaris species exhibited lower accuracy in this study than in previous ones. Nonetheless, the success rates for Papaver rhoeas and Phalaris paradoxa L. were still above 70%. Conclusion: Models for C. diluta, B. diandrus, L. rigidum, Papaver rhoeas and Phalaris paradoxa have demonstrated potential for adoption in commercial production, while Phalaris minor and Phalaris brachystachys models require refinement. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

This study was conducted to investigate the impact of industrial activities on heavy metals status in wastewater, sludge and flora on the bank of selected main drains of the Hayatabad Industrial estate, Peshawar. Plants, sludge and wastewater samples of selected sites were collected and analyzed for heavy metals distribution; cadmium (Cd), chromium (Cr), lead (Pb) and zinc (Zn) levels. Bioconcentration factor (BCF) values were calculated for plants (Phalaris minor) grass species found naturally at all sites. The results showed that the levels of metals in wastewater were lower than permissible limits except Cd and the concentration of metals in plants and sludge were within permissible limits when compared to their respective standards. Metal distribution was in the following order; sludge > plants > wastewater and the concentration of metals varied according to the distance from the source with no specific pattern. Sludge samples for all sites showed a high concentration of metals as compared to plants and wastewater samples. In grass samples, Zn was highest and Cd was low for all sites. Metals accumulation in plants was in order of; roots > shoot. Pearson's coefficient correlation showed that Cr in plant roots and Zn in shoots showed significantly high correlation with Cd in sludge while Pb in roots showed significant negative correlation with Zn in sludge. BCF values for Cr, Pb and Zn were >1, showing the phytoremediation potential of plants.

Field and pot investigations were conducted to determine the effectiveness of pyroxasulfone alone and its combinations with other herbicides against diverse weed flora of wheat (Triticum aestivum L.) including multiple herbicide‐resistant (MHR) littleseed canarygrass (Phalaris minor Retz.). Applications of pyroxasulfone 100–127.5 g/ha as pre‐emergence (PE) or early post‐emergence (EPOE) @ 63.75 g/ha at 21–23 days after sowing (1 day before irrigation) were highly effective for control of grass weeds namely P. minor and wild oat (Avena ludoviciana Dur.). It was poor for control of broad‐leaved weeds (Medicago denticulata Willd. and Rumex dentatus L.). However, pyroxasulfone in tank‐mix combination with metsulfuron 4 g/ha, triasulfuron 20 g/ha, and pyroxsulam 18 g/ha effectively controlled (96.5%–99.8%) the diverse weed flora and improved the wheat grain yield (69.5%–285.9%) over untreated weedy control. Also, the pre‐mix of pyroxasulfone + pendimethalin applied as PE was superior to either of these applied alone for weed control and grain yield. Pyroxasulfone 100–127.5 g/ha had yield gain of 119.6%–125.4% and 10.1%–26% over untreated control and pendimethalin 800–1250 g/ha, respectively. In pot studies, straw burnt ash drastically reduced the pyroxasulfone efficacy against P. minor and A. ludoviciana. Pyroxasulfone was also effective in pot studies for control of MHR P. minor having resistance against acetyl‐coA carboxylase (ACCase), acetolactate synthase (ALS), and photosynthesis at the photosystem‐II site‐A (PS‐II) inhibitor herbicides (clodinafop, sulfosulfuron, and isoproturon, respectively). The studies indicate that pyroxasulfone as PE or EPOE can be an alternative grass weed control herbicide in wheat in particular for the control of MHR P. minor. [ABSTRACT FROM AUTHOR]

Based on the chemical properties of herbicide and carrier water, water hardness might have different impacts on herbicide performance. A study was conducted in the greenhouse to determine the effect of chloride and bicarbonate forms of Mg+2 and Na+ on the performance of clodinafop-propargyl and sulfosulfuron for littleseed canarygrass control. The concentrations of bicarbonate and chloride forms of Mg+2 and Na+ had no significant effect on the ED50 of clodinafop-propargyl. The relative potency of clodinafop-propargyl, in the presence of all mineral salts, was 1.0 or had no significant difference from 1.0. On the contrary, increasing the mineral salts reduced the ED50 of sulfosulfuron significantly, especially in the presence of bicarbonate forms of Mg+2 and Na+. In this regard, the relative potency of sulfosulfuron as affected by 100 to 800 ppm Mg(HCO3)2 was about 0.5 to 0.7 times higher than control. This value was increased from 0.5 to 2.2 at 100 to 800 ppm sodium bicarbonate. Hence, the ranking of the mineral salts on improving sulfosulfuron performance was NaHCO3 > Mg(HCO3)2 > MgCl2 > NaCl. It is suggested that because of the lipophilic nature of clodinafop-propargyl, the presence of mineral salts did not affect the performance of this herbicide. It is concluded that, in determining the effect of water hardness on herbicide performance, in addition to chemical properties of herbicide, type of mineral salt, and its concentration, it is also essential to know the changes in the pH of the carrier water due to the mineral salts.

Abstract Modelling was carried out using maximum entropy model (MaxEnt) to explore and predict the invasion potential of littleseed canarygrass (Phalaris minor Retz.) in India under current as well as future climatic conditions under Representative Concentration Pathways (RCPs) 4.5 and 8.5 for the years 2050 and 2070. Mutually least correlated 8 bioclimatic variables along with soil and elevation data were used for the modelling over 223 occurrence locations of the species. Jackknife test revealed the significance of temperature derived variables viz. temperature seasonality, annual mean temperature and minimum temperature of the coldest month in governing the potential distribution of P. minor. Currently, 21% of India’s area is either highly (9%) or moderately (12%) suitable as habitat for P. minor. Our model predicts approximately 90% contraction in the area considered to be highly or moderately suitable climatically between 2050 and 2070 under both moderate and high emissions scenarios. Thus, under future climate, a significant niche shift by the species and decreased suitability was observed compared to the current distribution. The present study is first of its kind in exploring the invasion potential of alien invasive weed P. minor under climate change scenarios which is a current threat to rice-wheat system in Indo-Gangetic plains of India. [ABSTRACT FROM AUTHOR]

The introduction and large scale cultivation of wheat cultivars which are semi-dwarf and high yielding in the north-western Indo-Gangetic Plains (IGPs) of India has led to the dominance of wheat mimicking weed, Phalaris minor Retz. Over the period, this weed has become a highly competitive and pernicious weed of wheat in rice–wheat cropping system resulting in huge yield losses. In 1978, the herbicide isoproturon was adopted on large scale to control P. minor in wheat fields and remained as most feasible option for its chemical control. However, P. minor populations have developed resistance over time as a result of continuos application of same herbicide. This herbicide resistance started from isoproturon with 0.8 m ha area to several herbicides like sulfosulfuron, clodinafop, metribuzin, fenoxaprop, pinoxaden, mesosulfuron + iodosulfuron and clodinafop + metribuzin in 7.5 m ha today. Out of 7.5 m ha, 3 m ha was observed under multiple herbicide resistance. To check the herbicide resistant P. minor populations, farmers adopted mixing post-emergence (POE) herbicides with metribuzin as well as its early POE application through fertilizer dust 2–3 days after first irrigation of wheat, and sequential application of pre-emergence (PRE) pyroxasulfone / pendimethalin / metribuzin followed by POE application of pinoxaden / clodinafop / mesosulfuron + iodosulfuron / clodinafop + metribuzin (low dose) in rice–wheat cropping zone of the IGPs of India. Therefore, considering the importance of herbicide resistance and its alarming situation in the region, this review presents the history of evolution of herbicide resistance in P. minor, its present status, management strategies and severity that causes a dent in the sustainability of wheat production under the rice–wheat cropping system of IGPs. In addition, for long-term management of resistance and maintenance of the sustainability of wheat yields, herbicides should be supplemented with integrated weed management strategies like soil solarization, crop rotation, use of crop residue management practices, growing of wheat cultivars with early crop vigour, timely application of herbicides with optimum dose, optimum seed rate, closer row spacing, use of microbial herbicides, exploring the potential use of allelochemicals and correct spray techniques are some of viable options for farmers to avoid losses from this troublesome weed and increasing wheat productivity. [ABSTRACT FROM AUTHOR]

Time-to-event methods have been proposed in the agricultural sciences, as one of the most suitable options for the analysis of seed germination data. In contrast to traditional linear/nonlinear regression, time-to-event methods can easily account for all statistical peculiarities inherited in germination assays, such as censoring, and they can produce unbiased estimates of model parameters and their standard errors. So far, these methods have only been used in combination with empirical models of germination, which are lacking biological underpinnings. We bridge the gap between statistical requirements and biological understanding by developing a general method that formulates biologically-oriented hydro time (HT), thermal time (TT) and hydrothermal time (HTT) models into a time-to-event framework. HT, TT, and HTT models are widely used for describing seed germination and emergence of plants as affected by the environmental temperature and/or water potential. Owing to their simplicity and the direct biological interpretation of model parameters, these models have become one of the most common tools for both predicting germination as well as understanding the physiology of germination responses to environmental factors. However, these models are usually fitted by using nonlinear regression and, therefore, they fall short of statistical rigor when inference about model parameters is of interest. In this study, we develop HT-to-event, TT-to-event and HTT-to-event models and provide a readily available implementation relying on the package “drc” in the R statistical environment. Examples of usage are also provided and we highlight the possible advantages of this procedure, such as efficiency and flexibility.

Time-to-event methods have been proposed in the agricultural sciences, as one of the most suitable options for the analysis of seed germination data. In contrast to traditional linear/nonlinear regression, time-to-event methods can easily account for all statistical peculiarities inherited in germination assays, such as censoring, and they can produce unbiased estimates of model parameters and their standard errors. So far, these methods have only been used in combination with empirical models of germination, which are lacking biological underpinnings. We bridge the gap between statistical requirements and biological understanding by developing a general method that formulates biologically-oriented hydro time (HT), thermal time (TT) and hydrothermal time (HTT) models into a time-to-event framework. HT, TT, and HTT models are widely used for describing seed germination and emergence of plants as affected by the environmental temperature and/or water potential. Owing to their simplicity and the direct biological interpretation of model parameters, these models have become one of the most common tools for both predicting germination as well as understanding the physiology of germination responses to environmental factors. However, these models are usually fitted by using nonlinear regression and, therefore, they fall short of statistical rigor when inference about model parameters is of interest. In this study, we develop HT-to-event, TT-to-event and HTT-to-event models and provide a readily available implementation relying on the package “drc” in the R statistical environment. Examples of usage are also provided and we highlight the possible advantages of this procedure, such as efficiency and flexibility.

Uncontrolled growth of Phalaris minor in the wheat (Triticum aestivum) crop has remained a problem, leading to a massive reduction in wheat grain production. Herbicides have been used to control the weed, which leads to the development of frequent resistance in P. minor and mutant biotypes were also reported (Trp2027Cys and Ile2041Asn). Development of resistance enforced agro researchers to analyses the action of herbicide on P. minor. In this study, the sequence and structure of P. minor and T. aestivum Acetyl CoA Carboxylase (ACCase) have been analysed to locate the differences in their sequence and structure and to formulate a plausible explanation of the selectivity of herbicides which may help in the rationale discovery of noble herbicides. The sequence and 3D structure analysis of weed and wheat ACCase indicate minute differences in the distantly located amino acid residues. However, proteins are conserved at the binding site of herbicides with no mutation at the catalytic site. Analysis indicates that herbicides selectively target P. minor ACCase might be due to unknown other reasons, but not due to differences in their protein sequence and structure. [ABSTRACT FROM AUTHOR]

Uncontrolled growth of Phalaris minor in the wheat (Triticum aestivum) crop has remained a problem, leading to a massive reduction in wheat grain production. Herbicides have been used to control the weed, which leads to the development of frequent resistance in P. minor and mutant biotypes were also reported (Trp2027Cys and Ile2041Asn). Development of resistance enforced agro researchers to analyses the action of herbicide on P. minor. In this study, the sequence and structure of P. minor and T. aestivum Acetyl CoA Carboxylase (ACCase) have been analysed to locate the differences in their sequence and structure and to formulate a plausible explanation of the selectivity of herbicides which may help in the rationale discovery of noble herbicides. The sequence and 3D structure analysis of weed and wheat ACCase indicate minute differences in the distantly located amino acid residues. However, proteins are conserved at the binding site of herbicides with no mutation at the catalytic site. Analysis indicates that herbicides selectively target P. minor ACCase might be due to unknown other reasons, but not due to differences in their protein sequence and structure.

The objective of the present work was to quantify the total phenolic, flavonoid and tannin contents, and determine the antioxidant activity and the allelopathic potentiality of the aerial part of seven medicinal plants collected from Tunisia against two target species, including Lactuca sativa (crop) and Phalaris minor (weed). After the calculation of the extraction yield, the phenolic compounds contents of the extracts were determined and the antioxidant and allelopathic activity of the extracts showing the best extraction yield values were evaluated. Total phenolic, flavonoid and condensed tannin contents were quantified spectrophotometrically using Folin-Ciocalteu, aluminum chloride and vanillin 4%, respectively as reagents, while the antioxidant activity was determined according to the DPPH scavenging activity and Ferric reducing antioxidant power assay. The allelopathic activity was evaluated by the calculation of the percentages of the inhibition or stimulation of seeds germination and the length of the hypocotyls and radicles. The results obtained revealed that 80%-aqueous MeOH extracts presented the best extraction yield values. In addition, 80%-aqueous MeOH extract of Cynoglossum creticum showed the highest contents of phenolic and flavonoid, while 80%-aqueous MeOH extract of Ammi majus had the highest content of condensed tannin. The results also showed that Cynoglossum creticum exhibited the best antioxidant activity determined by the DPPH and FRAP assays. Moreover, Cynoglossum creticum, Echium plantagineum and Echium arenarium showed total inhibition of the Phalaris minor seeds germination, radicles and hypocotyls length at a concentration of 6 mg/mL, while Anchuza azurea and Borrago officinale extracts showed the highest stimulation of the radicles and hypocotyls length at 3 mg/mL. Furthermore, Echium arenarium showed the highest inhibition of Lactuca sativa seeds germination, radicles and hypocotyls length at the concentration 9 mg/mL, whereas, Opuntia ficus indica extract presented the highest stimulatory effect of the seed germination and hypocotyl length at 3 mg/mL. These results make Cynoglossum creticum a suitable source of allelochimicals potentially usable to control weeds. [Display omitted] • C. creticum 80% aqueous MeOH extract shows the highest polyphenol and flavonoid contents and the best antioxidant activity. • C. creticum, E. plantagineum and E. arenarium methanolic extracts provoke a total inhibition of germination at 6 mg/mL against P. minor. [ABSTRACT FROM AUTHOR]

Wheat (Triticum aestivum) is a vital cereal crop and a staple food source worldwide. However, wheat grain productivity has significantly declined as a consequence of infestations by Phalaris minor. Traditional weed control methods have proven inadequate owing to the physiological similarities between P. minor and wheat during early growth stages. Consequently, farmers have turned to herbicides, targeting acetyl-CoA carboxylase (ACCase), acetolactate synthase (ALS) and photosystem II (PSII). Isoproturon targeting PSII was introduced in mid-1970s, to manage P. minor infestations. Despite their effectiveness, the repetitive use of these herbicides has led to the development of herbicide-resistant P. minor biotypes, posing a significant challenge to wheat productivity. To address this issue, there is a pressing need for innovative weed management strategies and the discovery of novel herbicide molecules. The integration of computer-aided drug discovery (CADD) techniques has emerged as a promising approach in herbicide research, that facilitates the identification of herbicide targets and enables the screening of large chemical libraries for potential herbicide-like molecules. By employing techniques such as homology modelling, molecular docking, molecular dynamics simulation and pharmacophore modelling, CADD has become a rapid and cost-effective medium to accelerate the herbicide discovery process significantly. This approach not only reduces the dependency on traditional experimental methods, but also enhances the precision and efficacy of herbicide development. This article underscores the critical role of bioinformatics and CADD in developing next-generation herbicides, offering new hope for sustainable weed management and improved wheat cultivation practices. © 2024 Society of Chemical Industry., (© 2024 Society of Chemical Industry.)

The present study was planned to identify the phenolic compounds and allelopathic effect of Glycyrrhiza glabra on germination and seedling growth Phalaris minor at Weed Science Laboratory, Department of Agronomy, University of Agriculture, Faisalabad during winter 2018. The experiments were laid out under a completely randomized design (CRD), having three replicates. In this study seven different concentrations of Glycyrrhiza glabra aqueous extracts (0%, 0.25%, 0.5%, 10%, 20%, 40% and 80%) applied on winter weed P. minor. Data on regarding germination percentage (%), mean Germination time (days), time to 50% germination, root length (mm), shoot length (mm), root fresh weight (mg), shoot fresh weight was recorded following standard procedures. Data were analyzed using Fishers Analysis of Variance. The differences among treatments were separated using a least significant difference test (LSD). Results of the experiment revealed that maximum germination percentage (%), Mean Germination time (Days), Time to 50% germination and minimum, root length (mm), shoot length (mm), root fresh weight (mg), shoot fresh weight of P. minor was recorded at 80% concentration of G. glabra. From the present study, it is concluded that there are phenolic compounds in the wood extract of G. glabra which cause allelopathic effects on P. minor. [ABSTRACT FROM AUTHOR]

Chemical weed regulator process may source ecological hazards and produce residual effects in crops as well as in soil. Another method to switch weeds is accomplishment special treatment in bearable production scheme. Practice of liquid residue of produces is receiving systematic consideration as environmental substitute to copied weed-killer specifically below rapid scheme of growing herbicide refusal in the production of weeds. Therefore, current research was directed at Science Laboratory of weed, Department of Agronomy, University of Agriculture, Faisalabad during winter 2018 to determine the phytotoxic impact proceeding Glycyrrhiza glabra on winter vegetable crop Pisum sativum. The trials were placed out further down an entirely randomized plan, showing three replicates. Some experiments comprised of seven treatments with different concentrations of extract. The wood of G. glabra extracts comprised 0%, 0.25%, 0.5%, 10%, 20%, 40%, and 80% concentration applied on P. sativum. Data on seed sprouting, the measurement of shoot and original mass of weed and pea was recorded following standard procedures. Data stayed investigated through Fishers Study of Variance. The differences among treatments were divided with the action of a least significant difference test (LSD). Results revealed that aqueous extracts were possessed phytotoxic chemicals that cause phytotoxic effect to P. sativum and result in maximum propagation ratio (%), Mean Sprouting period (Days), Period to 50% germination and minimum, the length of root (mm), shoot dimension (mm), root fresh weight (mg), shoot fresh weight was recorded at 80 % concentration of G. glabra. It is concluded that there are phenolic compounds in the wood extract of G. glabra which cause allelopathic effects on P. sativum. [ABSTRACT FROM AUTHOR]

Phalaris minor is a major weed of wheat crop which has evolved resistance against herbicides. Isoproturon is the most accepted herbicide developed resistance in 1992. Later, introduced herbicides also developed resistance and cross-resistance to their respective binding sites. Isoproturon binds at the QB binding site of the D1 protein of photosystem-II (PS-II), which blocks the electron transfer in photosynthesis. In this work, we have carried out a series of computational studies to prioritize the promising herbicides against D1 protein of P. minor. Through the computational studies, twenty-four lead molecules are prioritized which have shown a higher binding affinity and inhibition constant than the reference ligand molecule. The binding and conformational stability of docked complexes was evaluated by molecular dynamics simulations and binding free energy calculations i.e., MM/PBSA. A list of amino acids such as Ala225, Ser226, Phe227, and Asn229 present in the binding site of protein is obtained to be playing an important role in the stability of the protein-lead complex via hydrogen bond and π-π interactions. Binding free energy calculation revealed that the selected lead molecule binding is energetically favorable and driven by electrostatic interactions. Among 24 leads, computational results have uncovered eight promising compounds as potential herbicides which have shown comparable physiochemical profile, better docking scores, system stability, H-bond occupancy, and binding free energy than terbutryn, a reference molecule. These prioritized molecules were custom synthesized and evaluated for their herbicidal activity and specificity through whole plant assay under laboratory-controlled conditions. The lead molecule ELC5 (6-ethoxy-4-N-(2-morpholin-4-ylethyl)-2-N-propan-2-yl-1,3,5-triazine-2,4-diamine) has shown comparable activity to the reference herbicide(isoproturon) against P. minor. [ABSTRACT FROM AUTHOR]

Rice (Oryza sativa L.)-wheat (Triticum aestivum L.) is the predominant cropping system of North Indian region. Due to continuous following of rice-wheat cropping system every year, weed infestation particularly in wheat, has emerged a major problem resulting in reduced wheat yield and nutrient mining. Integration of suitable planting methods, along with effective weed control measures, can reduce the weed infestation and nutrient mining from the soil and can enhance available plant nutrients in the soil. To evaluate the influence of different planting techniques and weed control practices in wheat on available plant nutrients in soil, a field study was conducted at the department of Agronomy, Punjab Agricultural University, Ludhiana (India) for two consecutive years. The treatments comprised of five planting techniques: conventional tillage, zero till sowing without rice stubbles, zero till sowing in standing rice stubbles , zero till sowing after partial burning of rice stubbles and bed planting and five weed control treatments i.e. clodinafop 60 g/ha, clodinafop 60 g/ha fb 2, 4-D 0.5 kg/ha, sulfosulfuron 25 g/ha, mesosulfuron + iodosulfuron 12 g/ha and unweeded (control). The experiment was conducted in split plot design with planting methods in the main plot and herbicidal treatments in the sub plot with three replications. The results of the study showed that zero till sowing of wheat in standing rice stubbles observed significantly higher soil organic carbon, available nitrogen, phosphorus and potassium than conventional till wheat sowing after removal of rice residues. Although partial burning of rice stubbles also showed positive trend in soil organic carbon, available nitrogen, phosphorus and potassium but retort was less distinct than rice stubbles without burning. Further, zero tillage alone also showed improvement in soil organic carbon and available nitrogen, phosphorus and potassium over conventional tillage. Application of herbicides did not diverge soil organic carbon, but significantly improved the available nitrogen, phosphorus and potassium content in soil than the unweeded (control).

Abstract Background Faba bean weeds are considered as serious pests that lead to pronounced damages to its agricultural production since they consume water and nutrients from the soil, reducing not only the yield but also the quality of the crops. So, the aim of this investigation is to control the weeds associated with faba bean plants. Materials/methods Two pot experiments were carried out during two successive winter seasons of 2016/2017 and 2017/2018 in the greenhouse of the National Research Centre, Dokki, Giza, Egypt. Treatments were applied by incorporating the dry leaf powder of Ficus nitida to the soil surface of pots at the rate of (0, 10, 20, 30, 40, 50, and 60 g/kg soil). Results All concentrations used pronouncedly decreased the fresh and dry weight of both Phalaris minor and Malva parviflora. On the other hand, Vicia faba growth as well as its yield and yield components were increased with most concentrations used as compared to their mixed controls. Treatments of 20, 30, and 40 g/kg soil, from F. nitida leaf powder, respectively recorded the highest increases in the most growth characters of V. faba with both weeds (P. minor and M. parviflora) at the two growth ages when compared to the healthy control. Also, the best results in all V. faba yield components were recorded with 20 g/kg soil of F. nitida treatment. Conclusion The results of the present study indicate the possibility of using the allelopathic activity of the leaf powder of Ficus nitida as a selective bioherbicide for controlling annual weeds accompanied Vicia faba plants.

Essential oil (EO) of Tagetes minuta L. extracted from aerial parts of plant through hydro-distillation was tested for its chemical composition by GC-MS. In order to explore the allelopathic potential of the oil, it was tested under laboratory conditions on a common agricultural weed Phalaris minor. The modes of oil application were volatile form (VB), solution form (SB) and oil mixed with agar-agar (AAB). Bioassay studies revealed a dose-dependent inhibitory effect of EO of T. minuta on growth of P. minor. Most effective mode of treatment was VB followed by AAB and minimum effect was observed in SB. Thus, volatile form of EO is best suitable for managing P. minor in agroecosystems. [ABSTRACT FROM AUTHOR]

Wheat is the staple cereal crop of Pakistan but its growth is rigorously affected by associated weeds. Present study evaluated the synergistic effect of plant antagonistic rhizobacteria and fungi on growth, yield and suppression of wheat-associated weeds. Wheat associated weeds Phalaris minor and Avena fatua were grown in pots containing wheat as well. Pseudomonas aeruginosa strain PAO1 and Trichoderma harzianum T-MN6 were used as amendments to check their effect on two major weeds of wheat. The combined application of PAO1 and T-MN6 reduced the shoot length of Phalaris minor up to 30% and Avena fatua 40%, root length 22% and 28%, fresh biomass 29% and 31% respectively over their sole application. Similarly, inoculation of PAO1 and T-MN6 alone and in combination considerably enhanced growth, yield and physiological parameters of wheat. It was inferred from this study that the synergistic application of PGPR and fungi is a promising option to suppress major weeds of wheat and to enhance growth and yield of wheat.

Phalaris minor Retz. is a major issue in wheat growing areas of Pakistan because it has evolved resistance to ACCase inhibitors herbicides like fenoxaprop due to enhanced metabolic activity to detoxify herbicides. Cytochrome P450 inhibitors such as 1- aminobenzotriazole (ABT) and malathion are expected to increase the toxicity of herbicides against ACCase resistant weeds. In this regard, a wire house experiment was carried to explore the effect of cytochrome P450 inhibitors on ACCase resistant P. minor biotypes. Seeds of nine ACCase resistant P. minor biotypes and susceptibility were sown in pots (5 seeds per pot). After seedling establishment (at 3-4 leaf stage), different doses of cytochrome P450 inhibitors (ABT at 50, 100 and 150 μM and malathion at 500, 1000 and 1500 g a.i. ha-1) were applied 30 minutes before spray of fenoxaprop at 67.5 g a.i. ha-1. Outcomes exhibited that cytochrome P450 inhibitors improved the herbicidal activity of fenoxaprop, significant decrease in fresh and dry weight of resistant biotypes were achieved. Maximum decrease in weight (fresh and dry) was noted for ABT at 50 μM, 100 μM and 150 μM+ fenoxaprop at 67.5 g a.i ha-1. Similarly, percent decrease in dry weight and mortality was also maximum when ABT at 50 μM, 100 μM and150 μM+ fenoxaprop at 67.5 g a.i ha-1 was used. Results conferred the resistance potential of P. Minor biotypes against fenoxaprop and P450inhibitors could be used to synergize the activity of fenoxaprop. [ABSTRACT FROM AUTHOR]

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The Phalaris genus includes annual weed species such as short-spiked canarygrass (Phalaris brachystachys Link.), little-seed canarygrass (Phalaris minor Retz.) and hood canarygrass (Phalaris paradoxa L.), which are especially problematic in Spain; as such, there is a need to develop models to predict the timing of their emergence. Field experiments were conducted at two different locations during two (2006/07 and 2007/08) and three (from 2005/06 to 2007/08) growing seasons. In both locations, 500 seeds of each Phalaris species were sown each growing season, simulating rain-fed cereal field conditions. In addition, the models were validated with three, four and eight independent experiments for P. brachystachys, P. minor and P. paradoxa, respectively. The emergence period of the three Phalaris species lasted between 31 and 48 days after sowing (DAS), showing two main flushes. The three cardinal points for parametric and non-parametric models were established to be between −1 °C and 1 °C for base temperature, between 9.8 °C and 11.8 °C for optimal temperature and between 21.2 °C and 23.4 °C for ceiling temperature; base water potential was estimated to be between −1 and −1.1 MPa. Both parametric and non-parametric models obtained similar results and were successfully validated in 12 out of 15 independent experiments.

ABSTRACT To test resistance status of Phalaris minor (littleseed canary grass) to fenoxaprop-P-ethyl in Pakistan, a field survey was conducted during 2014. Uncontrolled P. minor plants were selected for seed collection from wheat fields where fenoxaprop-P-ethyl was used to control P. minor. Seeds were collected from eight different locations near Fasialabad, Pakistan. Susceptible plants were also selected near Faisalabad having no history of fenoxaprop-P-ethyluse for comparison. These seeds were grown in pots for resistance confirmation using completely randomized design with factorial arrangement having four replicates. Four doses of fenoxaprop-P-ethylcontrol (0X), 46.9 (0.5X), 93.7 (1X) and 187 (2X) g a.i. ha-1 were sprayed at 3 to 4 leaf stage of P. minor. Three weeks after fenoxaprop-P-ethyl spray, percent mortality and biomass of different biotypes were recorded. Dose killing 50% plants (LD50) and resistance index (RI) were calculated on the basis of percent mortality. Results revealed that out of eight biotypes (PM-FS-1, PM-FS-2, PM-FS-3, PM-FS-4, PM-FS-5, PM-FS-6, PM-FS-7 and PM-FS-8) four biotypes (PM-FS-1, PM-FS-2, PM-FS-6 and PM-FS-7) showed resistance to fenoxaprop-P-ethyl. Percent mortality for the resistant biotypes was 51 to 71% even at 2X. Resistance index of the resistant biotypes was 2.13-6.00. Biomass reductions were also significantly lesser in resistant biotypes. Evolution of P. minor resistance to fenoxaprop-P-ethyl is first case of herbicide resistance in Pakistan. Research is needed to assess the infestation of herbicide resistant P. minor area in other locations and suggest control measures to evolve the effective management strategy to control the future spread of resistant biotypes.

Wheat is the staple cereal crop of Pakistan but its growth is rigorously affected by associated weeds. Present study evaluated the synergistic effect of plant antagonistic rhizobacteria and fungi on growth, yield and suppression of wheat-associated weeds. Wheat associated weeds Phalaris minor and Avena fatua were grown in pots containing wheat as well. Pseudomonas aeruginosa strain PAO1 and Trichoderma harzianum T-MN6 were used as amendments to check their effect on two major weeds of wheat. The combined application of PAO1 and T-MN6 reduced the shoot length of Phalaris minor up to 30% and Avena fatua 40%, root length 22% and 28%, fresh biomass 29% and 31% respectively over their sole application. Similarly, inoculation of PAO1 and T-MN6 alone and in combination considerably enhanced growth, yield and physiological parameters of wheat. It was inferred from this study that the synergistic application of PGPR and fungi is a promising option to suppress major weeds of wheat and to enhance growth and yield of wheat. [ABSTRACT FROM AUTHOR]

Two pot experiments were carried out during two successive winter seasons of (2016/2017) and (2017/2018) at the green house of National Research Centre (NRC), Giza, Egypt. The experiments were conducted to compare the allelopathic effect of Beta vulgaris (shoot and root aqueous extracts at 3%, 6%, 9%) to chemical herbicides (Topik and Basagran) at recommended doses (140 g fed-1 and 1 L fed-1, respectively) in controlling weeds (Phalaris minor and Malva parviflora) associated with Lupinus albus plants. Results showed that all applied aqueous extracts caused reduction in two weeds biomass under investigation. Meanwhile, root aqueous extract was more effective than shoot aqueous extract in controlling weeds. It is worthy to mention that phenolic compounds and flavonoids in B. vulgaris root aqueous extract were higher than that in B. vulgaris shoot aqueous extract. In addition, all applied aqueous extracts increased growth, yield and yield components of L. albus plant. The inhibitory effect of B. vulgaris aqueous extract on weeds or its stimulatory effect on L. albus plants increased by increasing the extracts concentration. The two applied herbicides gave complete eradication of both weeds depending on selectivity of each herbicide followed by root aqueous extract of B. vulgaris at 9%; this in turn reflected on L. albus plants by scoring highest results as compared to unweeded treatment. [ABSTRACT FROM AUTHOR]

The experiment was designed to study allelopathic effect of Rhazya stricta Decne. against selected weeds of wheat crop by using aqueous, hexane and methanolic extracts on filter paper and soil. The germination percentage, radicle length and plumule length were observed. The results revealed that R. stricta methanolic extract showed the highest degree of seed germination percentage inhibition of C. album, P. minor and R. dentatus with 47%, 43% and 42%, respectively in soil, and minimum germination for C. album (53%). The same extract caused significant radical length reduction of R. dentatus and A. fatua measuring 51% and 50%, respectively. The highest degree of inhibition in plumule length was measured for A. fatua and R. dentatus with 55% and 34%, respectively by R. stricta methanolic extract. Based on the results, it can be concluded that R. stricta showed good allelopathic activity that may be used in future herbicide screening program to launch in the market. [ABSTRACT FROM AUTHOR]