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Advances in Weed Science, Volume: 40, Published: 2022
  • Herbicidal efficacy of culture filtrates of Alternaria brassicicola and Alternaria gaisen against parthenium weed Research Article

    Kausar, Tehmina; Jabeen, Khajista; Javaid, Arshad; Iqbal, Sumera

    Abstract in English:

    Abstract: Background: Parthenium hysterophorus L. is one of the top ten worst weeds globally and is recorded in the global database of invasive species. Objective: The current study was aimed to evaluate the herbicidal potential of Alternaria brassicicola (Schwein.) Wiltshire and Alternaria gaisen Nagano. culture filtrates against a problematic weed P. hysterophorus. Methods: A. brassicicola and A. gaisen culture filtrates were tested in vitro against the test weed. A. gaisen culture filtrates were found most effective against the test weed, and this test fungus was partitioned with various fractions viz. n-hexane, chloroform, ethyl acetate and n-butanol were isolated. In vitro bioactivity of these fractions were tested against P. hysterophorus. The most productive n-hexane fraction was subjected to GC-MS analysis, and thirteen compounds were identified. Results: A. gaisen original (100%) and diluted (50%) culture filtrates showed significant herbicidal activity against P. hysterophorus. However, culture filtrates of A. gaisen suppressed the germination, root and shoot growth of the test weed to a greater extent compared with culture filtrates of A. brassicicola . Original culture filtrates of A. gaisen significantly reduced germination of P. hysterophorus by 88% as compared to diluted concentration by 56% in comparison with control. On the other hand, original and diluted culture filtrates of A. brassicicola reduced the germination of P. hysterophorus by 69% and 50%, respectively, over control treatment. The n-hexane fraction was found more effective in suppressing the P. hysterophorus growth as compared to other fractions. Both 0.10% and 0.05% concentrations of n-hexane fraction significantly inhibited P. hysterophorus seedlings germination by 88% and 81%, respectively. The n-hexane fraction was subjected to GC-MS analysis, and thirteen compounds were identified. Among these, ocimene (27.63%); benzene 1-ethyl-3-methyl-(20.30%) and n-hexadecanoic acid (10.27%) were major compounds. Conclusion: The present study concludes that A. gaisen culture filtrate has substantial herbicidal potential against P. hysterophorous.
  • Multiple resistance in goosegrass to clethodim, haloxyfop-methyl and glyphosate Research Article

    Nunes, José J.; Werle, Rodrigo; Freitas, Marco A. M. de; Cunha, Paulo C. R. da

    Abstract in English:

    Abstract Background Goosegrass is one of the most troublesome weed species in Brazil due to its wide dispersion and the ability to evolve herbicide resistance. Objective Investigate the response of goosegrass accessions from Mato Grosso, Brazil to glyphosate, clethodim, and haloxyfop. Methods Goosegrass seed samples were collected from seventeen production fields (accessions) in Mato Grosso and screened with the recommended label rates of clethodim, haloxyfop-methyl, and glyphosate. Six accessions withstood the label rate of the evaluated herbicides and were subjected to a dose-response study. Out of the six accessions, two were selected for further F1 dose-response investigations due to their ability to survive the label rate of the three herbicides individually. All studies were conducted under greenhouse conditions in a completely randomized design with four replications, and the F1 dose-response study was replicated in time. Results All six accessions investigated in the dose-response study presented ED50 values higher than susceptible plants for control and biomass reduction. Haloxyfop-methyl had the highest resistance ratios, followed by clethodim and glyphosate. The two accessions investigated in the F1 dose-response study were confirmed to be cross-resistant to clethodim and haloxyfop-methyl and showed low-level resistance to glyphosate. Conclusions The continuous reliance of POST herbicides for weed management in Mato Grosso cropping systems has selected goosegrass accessions that can withstand high rates of ACCase-inhibiting herbicides, particularly haloxyfop-methyl. Moreover, two accessions with resistance to ACCase-inhibiting herbicides, clethodim and haloxyfop-methyl, and low-level resistance to glyphosate were identified, suggesting the presence of multiple resistance in goosegrass accessions from Mato Grosso, Brazil.
  • Weed management in Roundup Ready® corn and soybean in Southern Brazil: survey of consultants’ perception Research Article

    Holkem, Aline S.; Silva, Anelise L. da; Bianchi, Mário A.; Corassa, Geomar; Ulguim, André R.

    Abstract in English:

    Abstract Background The presence of weeds in Roundup Ready® (RR) soybean and corn crops compromises yield. Management practices recommended by the consultants and adopted by producers directly interfere in the occurrence of these species. Objective To survey management practices used in RR soybean and corn fields in the Rio Grande do Sul. Methods Data were gathered via the application of questionnaires during the 2018/19 growing season to consultants working with RR soybean and corn cropping in Rio Grande do Sul state. There were 112 responses, covering about 72 municipalities in the state. Results Technical consultants highlighted Conyza spp. and Lolium multiflorum as the most common weed species and classified resistance to herbicides and advanced stages of weeds at the time of herbicide application as the primary causes of low weed control efficacy. They observed an increase in resistance evolution and a two to three-fold increase in the use of herbicides in glyphosate-tolerant crops. Using a mixture of herbicides was the main recommendation for the management of weeds that escape control, while in areas with proven resistance, crop rotation was the main recommendation. Conclusions Crop rotation and herbicide mixtures are the most recommended management practices, with herbicide resistance and advanced stage of development listed as the main reasons for the difficulties of weed control.
  • Selective weed control in white oat cultivars with als-inhibiting herbicides Research Article

    Xavier, Elouize; Trezzi, Michelangelo M.; Oliveira, Marisa de C.; Vidal, Ribas A.

    Abstract in English:

    Abstract Background The limited number of selective herbicides for white oat (Avena sativa L.) cultivation makes it managing weeds a challenge. Currently, few herbicide options are available for selective weed control in winter crops. Previous studies have indicated that ALS-inhibiting herbicides could be potential alternatives, so studies were conducted. Objective To characterize the tolerance level of white oat cultivars to ALS-inhibiting herbicides and to evaluate the level of weed control by applying penoxsulam and bispyribac-sodium. Methods Tolerance (%) was determined for white oat cultivars UFRGS 14, URS Guará, URS Guria, UFRGS 18, and URS Taura for imazethapyr, iodosulfuron, penoxsulam, and bispyribac-sodium dose-response. Also, the control efficiency of different doses of penoxsulam and bispyribac-sodium was determined on weed species of white oat, namely crabgrass (Digitaria horizontalis), siberian motherwort (Leonurus sibiricus), italian ryegrass (Lolium multiflorum), and wild radish (Raphanus raphanistrum). Results Imazethapyr and bispyribac-sodium were the least selective herbicides, whereas iodosulfuron had intermediate selectivity, and penoxsulam was the most selective for the white oat cultivars tested, with average control of 100, 72, 62.7 and 40%, respectively. Overall, bispyribac-sodium had a higher level of weed control (77.1%) than penoxsulam (62%). Label doses of penoxsulam and bispyribac-sodium resulted in low control levels of crabgrass. Conclusions All doses of bispyribac-sodium effectively control wild radish and italian ryegrass. The recommended dose of penoxsulam was selective for some cultivars of white oat and effectively controlled italian ryegrass and wild radish.
  • Spatial Abundance of Soil Seed Bank in Parthenium Infested Maize Fields in Western Gojjam Zone, Ethiopia Research Article

    Million, Dinberu; Nigatu, Lisanework; Bekeko, Zelalem

    Abstract in English:

    Abstract Background The reserve of viable weed seeds present on the soil surface and scattered throughout the soil profile. Objective A glasshouse study was conducted to determine the special abundance of soil seed bank flora in parthenium invaded maize fields in West Gojjam Zone. Methods The soil samples were collected from 90 fields at 0-5 cm, 5-10 cm and 10-15 cm soil depth with 10 cm width. Results A total of 121 weed species belonging to 27 families were found in the soil seed banks. The most frequent families were Poaceae (31 species), Asteraceae (21 species) and Leguminosae (9 species). The highest importance value was recorded by Parthenium hysterophorus, Ageratum conyzoides and Echinochloa colona with 19.05, 19.02 and 14.37%, respectively at 0-5 cm soil depth. The highest importance values of 20.39, 20.16 and 16.54% were registered by P. hysterophorus, A. conyzoides and Galiansago parviflora, respectively at 5-10 cm soil depth. Likewise, at 10-15 cm soil depth highest importance value was recorded by A. conyzoides, P. hysterophorus and E. colona with 19.12, 17.30 and 116.13%, respectively. The Shannon diversity index at 0-5, 5-10 and 10-15 cm soil depth were 4.46, 4.41 and 4.17, respectively. High similarity (68.10%) was observed between 0-5 and 5-10 and followed by 5-10 and 10-15 cm (60.19%) and 0-5 and 10-15 cm (55.39%). Conclusions These results could help to predict infestation potential and could lead to improved weed management strategies in maize growing areas in the study area.
  • Imidazolinone herbicide dissipation in rice fields as affected by intermittent and continuous irrigation Research Article

    Junkes, Gustavo V.; Avila, Luis A.; Kemmerich, Magali; Gehrke, Vinicios R.; Fipke, Marcus V.; Camargo, Edinalvo R.

    Abstract in English:

    Abstract Background: Clearfield® (CL) rice is one of the most successful tools for selective weedy rice control, using imidazolinone herbicides (IMI). However, IMI have residual soil activity and may carryover to non-tolerant crops growing in succession. It is necessary to find options to reduce IMI persistence in paddy rice fields. Objective: Evaluate the effect of water management on IMI dissipation in rice paddy and its carryover to soybean and non-CL rice. Methods: The herbicide mixture of imazapyr and imazapic totalizing 147 g a.i. ha−1 and 49 g a.i. ha−1, respectively, was applied half in preemergence (S3 stage – rice spike stage) and the other half in postemergence (V3-V4 rice stage). After herbicide application, a total of 21 samples were taken for analysis of residues. Soil samples were air dried and herbicides residues were analyzed using high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). Results: Calculated field dissipation half-life (DT½) of imazapyr was 182.5 and 42.0 days in continuous flooding and intermittent water management, respectively. Imazapic had a DT½ of 96.3 days on intermittent water management. No adjustment for the dissipation regression parameters was obtained for imazapic in continuous water management. No reduction in yield components was observed in soybean when grown in soil with imidazolinone residues. On the other hand, non-CL rice showed decreased shoot dry weight and stem number. Conclusion: Imidazolinone herbicides have a longer half-life under continuous rice water management than intermittent. Therefore, growers can use intermittent irrigation in ares prone to IMI carryover and can use soybean in rotation.
  • Distribution and resistance of barnyardgrass to quinclorac in rice fields in Thailand Research Article

    Pinsupa, Jarunya; Chindakul, Aussanee; Intanon, Suphannika

    Abstract in English:

    Abstract: Background: In Thailand, Echinochloa crus-galli (L.) P. Beauv. (barnyardgrass) is the most problematic weed in rice. Quinclorac was first commercialized in 1997 in Thailand and became the primary herbicide option for barnyardgrass control. The intensive use of quinclorac in rice fields increases the risk of the evolution of resistant barnyardgrass. Objective: This study was conducted to survey the occurrence of quinclorac-resistant barnyardgrass in Thailand, investigate the levels of quinclorac resistance, and evaluate alternative control measures for quinclorac-resistant barnyardgrass. Methods: Seeds of barnyardgrass were collected from 165 rice fields, located in 27 provinces of Thailand, and screened for quinclorac resistance. A whole-plant dose-response study was conducted on a susceptible population and three resistant populations to evaluate the resistance level. In addition, effectiveness of alternative herbicides including bispyribac, fenoxaprop, penoxsulam, profoxydim, propanil, and pyribenzoxim were evaluated using the selected populations. Results: Quinclorac-resistant barnyardgrass was identified in 121 rice fields (73%). Five sites (3%) exhibited developing barnyardgrass resistance to quinclorac whereas barnyardgrass populations in thirty-nine sites (24%) were susceptible to quinclorac. The evaluated resistant populations were at least 93-fold more resistant to quinclorac than the susceptible population. Profoxydim and propanil provided effective control of the two quinclorac-resistant barnyardgrass populations. One population (B56) exhibited no shoot biomass reduction after treatment either with quinclorac or bispyribac, suggesting multiple resistance to auxin mimics and ALS-inhibiting herbicides. Conclusions: Quinclorac-resistant barnyardgrass cases were confirmed in Thailand. The resistant barnyardgrass populations were broadly distributed on major rice-production areas of Thailand. Multiple-resistance in a quinclorac resistant population requires further investigation.
  • Multiscale properties of weeds in no-till system Research Article

    da Silva, Daniel M.; Mendanha, José F.; Buss, Ricardo N.; Siqueira, Glécio M.

    Abstract in English:

    Abstract Background Weeds have high spatial variability and show clustering behavior, with heterogeneity in scales that can be evaluated through multifractal analysis. Objective The objective of this study was to evaluate the spatial variability of weeds using multifractal analysis in a no-till area. Methods Sampling was conducted at 1,015 sampling points in an experimental plot with a regular grid of 5 × 5 m (2.38 ha) with no tillage. The area was cultivated with triticale (Triticum secale), and in the summer of 2011, the area was cultivated with soybean (Glycine max). Data were analyzed using descriptive statistics and multifractal analysis using the box-counting method to determine the scaling properties of the variables. Results The predominance of Raphanus raphanistrum was identified in the winter crop and Commelina ssp. during the summer. The singularity spectrum showed greater asymmetry for Raphanus raphanistrum and Commelina ssp. in relation to the category of other weeds (OW). The degree of multifractality varied throughout the study period, showing the ecological patterns of the studied species. Scale heterogeneity was revealed, with different degrees of multifractality that evidenced the processes of dispersion and colonization of the environment by the different weed species evaluated. Conclusions The species Raphanus raphanistrum and Commelina ssp. showed domains of low measurement values, and OW was the most heterogeneous.
  • An Insight of Quinclorac Resistance Mechanism in Early Watergrass ( Echinochloa oryzoides ) Research Article

    Haq, Muhammad Zia Ul; Zhang, Zheng; Qiang, Sheng; Ahmad, Ramala Masood; Abdulmajid, Dina; Fiaz, Muhammad

    Abstract in English:

    Abstract Background Quinclorac- main herbicide targeting to barnyard grass, has been used for decades in rice fields. Echinochloa species have been reported evolving into quinclorac resistance.Objective: Quinclorac resistance and its mechanism remain undisclosed in Echinochloa oryzoides (Ard.) Fritsch that needs to be uncovered. Methods Dose-response assays were performed, followed by ethylene synthesis, and related enzyme activities along with gene transcription were studied. β-CAS activity and its molecular docking were investigated. Results E. oryzoides evolved into 21 times resistance to quinclorac from Jiangsu province of China. The increment in ethylene levels in this biotype was correlated negatively with the level of resistance and positively with quinclorac-induced growth inhibition. Ethylene response pathway determination showed that resistant biotype decreased 1-aminocyclopropane-1-carboxylic acid (ACC) contents, related enzyme activities, and transcription of ACS and ACO genes. These results indicated that ethylene biosynthesis inhibition and quinclorac resistance possessed a positive correlation. Resistant biotype exhibited ~ 2-fold more β-CAS activity than susceptible ones. Resistant EcCAS gene depicted nucleotide changes as compared to susceptible ones, which resulted in two amino acid substitutions (Met-287-Lys and Thr-352-Ala). Consequently, resistant β-CAS enzyme exhibited an increase in binding residue in active site (simulation modelling); that can be the probable reason for higher enzyme activity in the resistant biotype. Conclusions The study concludes that variation in response pathway of auxin and potentially improved cyanide degradation were plausible mechanisms endowing quinclorac resistance in E. oryzoides .
  • Native range efficacy assessment of Calophya terebinthifolii , a candidate biological control agent of Schinus terebinthifolia in Florida, USA Research Article

    Cuda, James P.; Vitorino, Marcelo D.; Bini, Larissa; Boeno, Marcus M.; van Senten, Edzard

    Abstract in English:

    Abstract Background Aroeira or Brazilian peppertree, Schinus terebinthifolia Raddi (Anacardiaceae: Rhoeae), is one of the worst invasive plants in California, Florida, and Hawaii, USA because of its wide distribution, adaptation to various habitats, toxicity, and demonstrated negative impacts on biodiversity. Chemical and mechanical methods provide only temporary control, are expensive, may damage native plants, and often create disturbance conducive to reinvasion by Brazilian peppertree and other invasive weeds. The leaflet galling psyllid Calophya terebinthifolii Burckhardt & Basset (Calophyidae: Calophyinae) is native to South America and recent studies have shown this insect attacks only Brazilian peppertree. Nymphs complete their development in open pit galls that create nutrient sinks, which divert resources away from normal plant growth and reproduction. Objective The objective of this study was to confirm the biological control potential of C. terebinthifolii . Methods We used a randomized complete block design with four treatments (chemical exclusion [control], natural infestation, low and high psyllid densities) replicated in space. Results At low densities, C. terebinthifolii significantly reduced flower production by 80.6% and 93.9%, respectively, compared to the chemical exclusion treatment. At high densities, the psyllid completely inhibited fruit production. Furthermore, leaf and stem biomass were significantly reduced following sustained attack by the psyllid C. terebinthifolii . Conclusions Overall, our results confirmed that feeding damage by this psyllid negatively impacts above ground vegetative growth and reproduction of Brazilian peppertree. Therefore, C. terebinthifolii should be considered for introduction into Florida for biological control of this invasive shrub.
  • Structural characterization of phosphinothricin N -acetyltransferase ( RePAT ) and the glufosinate-resistant analysis for site-directed mutagenesis of RePAT in Arabidopsis thaliana Research Article

    Xu, Shixiao; He, Lingxiao; Sun, Jutao; Zhang, Zhiqiang; Yang, Tiezhao; Xue, Gang; Ding, Yongle

    Abstract in English:

    Abstract Background Transferring herbicide resistance genes to plant cultivars is one of the most effective methods for managing weed growth in agricultural land. The RePAT gene, previously isolated from the marine bacterium Rhodococcus sp . strain YM12, was found to provide glufosinate resistance to plants. Objective In this study, we further investigated the protein structure and function of RePAT isolated from the marine. Methods The physicochemical properties, two-dimensional structure, three-dimensional structure, and functional domains of the RePAT protein were analyzed and predicted using bioinformatics tools, and RePAT was optimized according to codon bias present in Arabidopsis thaliana . Site-directed mutagenesis of RePAT was performed, and the wild-type ( RePAT ) and mutant ( RePAT V120I ) genes were successfully transferred into A. thaliana . Results Our results showed that RePAT was an unstable hydrophilic protein, and six phosphorylation sites and two N-glycosylation sites were predicted. In addition, conserved domains containing the NAT_SF super family and coenzyme A-binding pocket were predicted in RePAT. Transgenic experiments and glufosinate resistance assays showed that the glufosinate resistance of A. thaliana containing the mutant gene ( RePAT V120I ) was lower than that of plants containing the wild-type gene, indicating that the missense mutation in RePAT V120I had a significant effect on its glufosinate resistance. Conclusions Our study provided improvement result for knowing the transferring herbicide resistance gene RePAT .
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