Digitaria Ciliaris Research Articles

Integracide derivatives produced by endophyte Fusarium armeniacum M-3 isolated from Digitaria ciliaris

Two new integracides, dedimethyl integracide B (1) and integracide K (2), were isolated from rice cultures of Fusarium armeniacum M-3, an endophyte isolated from Digitaria ciliaris, together with the known terpenoids, integracide B (3) and 2-deoxy-integracide B (4). Assignment of the signals in the 1H and 13C NMR spectra of 1 and 2 was achieved using DEPT, HMQC, HMBC, and NOESY spectra. Compound 2 exhibited moderate cytotoxicity against HeLa cells.

Analisis Keragaman Gulma Pada Tanaman Jagung Di Kelompok Tani Usaha Maju, Desa Naibonat, Kecamatan Kupang Timur, Kabupaten Kupang

The purpose of this study was to analyze the diversity of weed species in corn plantingsin the Usaha Maju Farmer Group, Naibonat Village, East Kupang District, Kupang Regency whichtook place from July to December 2020. Observation of weeds was carried out using the quadraticmethod. Observations in the sample plots by making observation subunits measuring 1 x 1 m2.Unknown weed species were collected and then identified using the Plant Snap application andmaking a herbarium. The results showed that there were 13 weed species found associated withcorn plants, namely Eleusine indica, Setaria pumila, Echinochloa colona, Cynodon dactylon,Digitaria ciliaris, Xanthium strumarium, Centela asiatica Ipomoea obscura, Euphorbia hirta,Tridax procumbens, Spigelia anthelmia, Passiflora foetida, and Phyllanthus niruri. Based onvegetation analysis, Eleusine indica and Euphorbia hirta were more dominant than other weedspecies with absolute densities of 20.5m2and 21.3m2per maize plant, respectively.

Influence of Mowing and Trampling on the Allelopathy and Weed Suppression Potential of Digitaria ciliaris and Cyperus microiria

A long-term, sustainable solution to weed infestation is extremely desirable because weeds have the potential to reduce crop productivity and the aesthetic appeal of the environment. In this study, the impacts of mowing and varying degrees of trampling pressure on the suppression of weeds, alongside wound-induced changes in the allelopathic potential, of the rhizosphere soil and the root exudates of southern crabgrass (Digitaria ciliaris) and Asian flatsedge (Cyperus microiria) were evaluated under both field and greenhouse conditions. The field study results showed that all trampling treatments induced the relative suppression of weed growth. Grass weeds showed higher resistance to trampling than broad-leaved weeds. However, laboratory bioassays showed that light trampling caused a significant increase in the growth-inhibitory effects of southern crabgrass rhizosphere soil on lettuce. Moreover, mowing (9.11% of control) and trampling (16.4% of control) resulted in a marginal increase in the growth-inhibitory effects of root exudates released from southern crabgrass. Furthermore, the growth-inhibitory activities of the Asian flatsedge rhizosphere soil were significantly reduced after heavy trampling pressure. Moreover, mowing and trampling resulted in marginal reductions in the growth-inhibitory activities of root exudates released from Asian flatsedge against lettuce (i.e., 18.7% and 28.5%, respectively). In general, mowing and varying degrees of trampling induced contrasting and integrated impacts on weed suppression as well as the allelopathic potential of both southern crabgrass and Asian flatsedge.

Biomonitoring-Supported Land Restoration to Reduce Land Degradation in Intensively Mined Areas of India

Land degradation due to mining is a major concern leading to massive losses of biodiversity and ecosystem services. The biomonitoring of metals in mine voids can help to keep track of ecosystem health. The present study was carried out in a large mine void that is presently used for fly ash disposal in the Angul district of Odisha, India. For the biomonitoring of the fly ash, composite soil and plant samples (non-edible as well as edible, naturally growing in and around the mine void) were collected seasonally four times between April 2018 and February 2019 from the sampling locations. We monitored the metal uptake (Al, Cd, Cr, Fe, Mn, Ni, Pb, Zn) and bioaccumulation to assess the bioaccumulation factor (BAF) in the collected plant samples. The Fe concentration was reported to be high in Tragia involucrate (24.82 mg/kg) and Digitaria ciliaris (24.818 mg/kg), while the soil at the study site is also rich in Fe and Al. Higher concentrations of metals in fruit trees such as Psidium guajava and other plants such as Ficus religiosa, Ipomoea batatas, Delonix regia, Digitaria ciliaris, and Cynodon dactylon were reported from nearby areas. Understanding the presence of metals should be a guiding factor for reducing land degradation. Our study stresses the need for corporate commitment to ensure regular biomonitoring and biomonitoring-supported land restoration for degraded mining areas. Sustainable land restoration supported by biomonitoring has the potential to help achieve the global goals of the UN Decade on Restoration: Land Degradation Neutrality (UNCCD) and Sustainable Development Goals (SDGs) 12, 13, and 15.

Evaluation of the food of red-billed quelea (Quelea. quelea) during off-cropping season in Gyawana ecosystem Adamawa State

The evaluation of the food items of red-billed quelea during off-cropping season in Gyawana ecosystem was carried out, to ascertain the wild food of Quelea quelea foraged on during off- cropping season. Red-billed quelea (Q, quelea) devastation of crops continues to be a problem that militates against food security in Adamawa State and other arid regions of Nigeria. The bird appears to have alternative food sources which ensure its survival and breeding during off- cropping seasons. The crop contents of Q, quelea were analysed. Nine (9) different food items were identified including seeds of different grasses, insect remains and Grits from the crops of one hundred and fifty (150) Q, quelea sampled for this study. Echinochloa colonum has the highest frequency and magnitude of occurrence in the food items foraged on by the Q, quelea with a mean value of 40.20±0.72, followed by Digitaria ciliaris (35.33±1.03), Digitaria iburua (29.96±1.12), Setaria pallidofusca (29.33±0.41), Roetboellia exaltata (21.67±0.25), Brachiaria mutica (1.71±0.16) and the least seed consumed is Cenchrus biflorus with a mean of 1.15±0.02. Grits was consumed in small quantity (0.15±0.36) by both sexes, while insects remained was observed only in female’s crop of the Quelea birds. Analysis of variance was used to compare the mean number of various seeds consumed by the Q, quelea during the period of the study. The result shows no significant difference in the food items consumed by Red-billed Quelea during off-cropping season at P >0.05. Based on the findings of this research work, the researchers therefore, recommend that further study should be carryout on the food items of Q, quelea during cropping season and also biological control of this Quelea birds (Q, quelea).

Herbicidal characteristics and structural identification of a potential active compound produced by Streptomyces sp. KRA18–249

The KRA18–249 strain, isolated from a natural recreational forest near Jeongseon, Gangwon-do, when applied to plants induced signs of wilting within 24 h, leading to plant death. The isolated actinomycete was identified as Streptomyces gardneri based on 16S rRNA gene homogeneity analysis. The culture filtrate was solvent fractionated to obtain the active substance, and the active compound 249-Y1 was isolated from the purified fractions via a herbicide activity test using Digitaria ciliaris. NMR and ESI–MS analyses revealed that the molecular formula of 249-Y1 is C20H16O6 [MW = 352.0947] and is an anthraquinone (rubiginone D2) produce by polyketide synthetase system. The active compound 249-Y1 showed strong (100%) herbicidal activity against several weeds at 500 μg mL−1 concentration. Twisting symptoms began to appear within 24 h of treatment and intensified over time. The KRA18–249 strain produced the herbicidal compound under specific culture conditions, that is, at 200 rpm, 35 °C, for eight days at an initial pH of 10. We also found that 249-Y1 inhibited chlorophyll, but was not a radical generator. Overall, the secondary metabolite 249-Y1, produced by KRA18–249, can be used as a new biological agent for weed control.

Effectiveness of napropamide herbicide controlling weeds on a golf course in Tropical Indonesia

Weeds existence interferes with the quality, aesthetics, and growth of golf course grass. Napropamide is a herbicide used to control broadleaf and grass weeds. Therefore, field experiments were employed during 2021 at Bandung Giri Gahana Golf Course, Jatinangor District, Sumedang Regency, West Java to determine effects of applying the herbicide in controlling weeds and on the growth of golf course grass. The experiment was laid out in randomized block design was used with six treatments, each of which was replicated four times. The treatments included manual hand weeding, a control, and different doses of Napropamide 50%, namely 6.75, 9, 11.25, and 13.5 kg/ha. The results showed that the herbicide Napropamide 50% with the dose of 6.75 kg/ha until 13.5 kg/ha were effectif to control grass weeds such as Eleusine indica, Panicum repens, Digitaria ciliaris and broad leaves weeds such as Cleome rutidosperma, Amaranthus viridis, Portulaca oleracea, up to 12 weeks after herbicide application without causing toxicity to golf course grass.

Synthesis, herbicidal activity study, and molecular docking of novel acylthiourea derivatives

A series of new acylthiourea derivatives were synthesized and characterized. The results of preliminary herbicidal activity tests showed that most compounds had good herbicidal activity against Digitaria adscendens and Amaranthus retroflexus, especially for compounds 4b (N-(2-chloro-4-methylsulfonylbenzoyl)-N’-(2-chlorophenyl) thiourea) and 4f (N-(2-chloro-4-methylsulfonylbenzoyl)-N’-(2,3-dichlorophenyl) thiourea). In vivo acetylhydroxylate synthase (AHAS) enzyme activity inhibition tests showed that all compounds had inhibitory activities against the enzyme at a concentration of 100 mg·L−1, with the highest inhibition rate up to 37.05% (compound 4f). In addition, molecular docking analysis was conducted by using the yeast AHAS as the target enzyme. The results of molecular docking were similar to the bioassay experiments, showing compounds 4b and 4f were potent inhibitors of AHAS.

Light and scanning electron microscopic imaging of leaf transverse sections of indigenous fodder grasses of central Punjab, Pakistan.

The significance of grasses as fodder is enormous. However, it has been observed that different fodder grasses are identified locally with the similar vernacular names. Even same species recognized with different names. This happened due to their reduced and overlapped morphological characters. Hence comprehensive taxonomic keys were required to provide authentic identification of this grass flora. Current study established microscopic identification tools on the basis of leaf transverse anatomical features. Results demonstrated a great diversity in ribs and furrows arrangement among all studied grass members. Lolium temulentum, Phalaris minor, Poa annua, Arundo donax, Aristida adscensionis, Desmostachya bipinnata, Cenchrus biflorus and Digitaria ciliaris possessed ribs and furrows only at adaxial surfaces whereas all other species possessed this feature abaxially. Generally all the species contain three types of vascular bundles i.e. small, medium and large. Therefore, this qualitative feature is valuable only at family level, however, it found insignificant in taxa identification. Diversity was observed in bundle sheath type which could be taxonomically significant. Generally bundle sheath was found complete in most of species but in Bromus japonicus Thunb., Dactylis glomerata L., Acrachne racemosa (Heyne ex Roth) Ohwi, Chrysopogon aucheri (Boiss.) Stapf, Dichanthium annulatum (Forssk.) Stapf, Heteropogon contortus (L.) P Beauv. Ex. Roem & Schult. Eragrostis minor Host. and in Agrostis gigantea Roth. had incomplete type of sheath. Results reported great diversity in characters which could be taxonomically viable. RESEARCH HIGHLIGHTS: This research highlighted the significance of microscopic examination of leaf transverse anatomical features in field of taxonomy. Established anatomical tools would be of great importance for the identification of studied species.

Digitaria ciliaris (southern crabgrass)

Digitaria ciliaris (southern crabgrass)

Effects of mulching on the weed community and grain yield of upland rice cultivars

This study evaluated the effects of mulching on upland rice cultivars Comecru and Cambará and the weed community under four amounts of babassou (Attalea speciosa Mart. ex Spreng.) straw mulching namely: 0, 15, 20, 25 t ha-1 with a view to control weeds. The experiment was laid out in a randomized complete block design in a 2 x 4 factorial scheme with four replications. The rice plant height, percentage of fertile panicles, number of spikelets per panicle, weight of 100 grains and grain yield were assessed. We also assessed the weed community by computing the following phytosociological parameters: density, frequency and the importance value index (IVI) of each species. Babassou straw mulching reduced weed density and dry mass between rows of upland rice cultivars and increased the rice yield. The weed species with the highest Importance Value Index (IVI) in the treatments with no mulching were Cyperus iria, Fimbristylis dichotoma and Digitaria ciliaris. Rice grain yield was increased with the increase in the amount of straw. Comecru cv. had the highest suppressive effect on weeds with significantly higher grain yield (1,214.85 kg-1) than Cambará cv. (878.72 kg ha-1). We conclude that the higher amounts (20 and 25 t ha-1) of babassou straw mulching suppressed weeds, providing less competition with the rice cultivars, which resulted in an increase in the number of rice panicles, weight of 100 grains, spikelet fertility and grain yield in both rice cultivars

Tomato Yellow Leaf Curl Virus Infection in a Monocotyledonous Weed (Eleusine indica).

Tomato yellow leaf curl virus (TYLCV) is one of the most important plant viruses belonging to the genus Begomovirus of the family Geminiviridae. To identify natural weed hosts that could act as reservoirs of TYLCV, 100 samples were collected at a TYLCV-affected tomato farm in Iksan from 2013 to 2014. The sample weeds were identified as belonging to 40 species from 18 families. TYLCV was detected in 57 samples belonging to 28 species through polymerase chain reaction using root samples including five species (Eleusine indica, Digitaria ciliaris, Echinochloa crus-galli, Panicum dichotomiflorum, and Setaria faberi) from the family Poaceae. Whitefly Bemisia tabaci-mediated TYLCV transmission from TYLCV-infected E. indica plants to healthy tomatoes was confirmed, and inoculated tomatoes showed typical symptoms, such as leaf curling and yellowing. In addition, TYLCV was detected in leaf and root samples of E. indica plants inoculated by both whitefly-mediated transmission using TYLCV-viruliferous whitefly and agro-inoculation using a TYLCV infectious clone. The majority of mastreviruses infect monocotyledonous plants, but there have also been reports of mastreviruses that can infect dicotyledonous plants, such as the chickpea chlorotic dwarf virus. No exception was reported among begomoviruses known as infecting dicots only. This is the first report of TYLCV as a member of the genus Begomovirus infecting monocotyledonous plants.

Uji Efektivitas Campuran Herbisida Berbahan Aktif Atrazin dan Topramezon terhadap Beberapa Jenis Gulma

The purpose of this study was to determine the effectiveness of mixing herbicides with the active ingredients atrazine and topramezone in controlling weeds and to determine the nature of the mixture of the two active ingredients. This research was conducted in a plastic house in Natar District, South Lampung Regency from October 2020 - January 2021. The study was arranged in a Completely Randomized Design (CRD). The treatments consisted of three types of herbicides with six dosage levels of the active ingredients, namely the single herbicide Atrazine 300 g/l (0, 37.5, 75, 150, 300, and 600 g ai ha-1), Topramezon 10 g/l (0. 1.25 , 2.5, 5, 10, and 20 g ai ha-1), and the herbicide mixture of Atrazine 300 g/l + Topramezone 10 g/l (0. 38.75, 77.50, 155, 310, and 620 g ai ha-1) , and repeated 6 times. The target weeds included broadleaf weeds (Ageratum conyzoides and Synedrella nodiflora), grass groups (Digitaria ciliaris, Echinochloa colonum, and Eleusine indica), and the puzzle group (Cyperus iria). The herbicides atrazine and topramezone have different ways of working so that the analytical method used is the Multiplicative Survival Model (MSM) method. The results showed that mixing the herbicide Atrazine 300 g/l + Topramezon 10 g/l had an expected LD50 value of 46.28 g ai ha-1 and a treatment LD50 of 27.22 g ai ha-1 with a co-toxicity value of 1.7 (Co-toxicity > 1) so that it is synergistic.Key words: Atrazin, Topramezon, mixing herbicide, Multiplicative Survival Model, weed, LD50

Eight Species of Poaceae Are Hosting Different Genetic and Pathogenic Strains of Sugarcane Mosaic Virus in the Everglades Agricultural Area.

Sugarcane mosaic virus (SCMV) was detected by reverse transcription polymerase chain reaction in eight different species of the Poaceae family in the Everglades Agricultural Area (EAA) of south Florida: broadleaf signalgrass (Urochloa platyphylla), Columbus grass (Sorghum almum), goosegrass (Eleusine indica), maize (Zea mays), sorghum (Sorghum bicolor), St. Augustine grass (Stenotaphrum secundatum), southern crabgrass (Digitaria ciliaris), and sugarcane (Saccharum interspecific hybrids). Based on their coat protein (CP) gene sequence, 62 isolates of SCMV from Florida and 29 worldwide isolates representing the known genetic diversity of this virus were distributed into eight major phylogenetic groups. SCMV isolates infecting Columbus grass, maize, and sorghum in Florida formed a unique group, whereas virus isolates infecting sugarcane in the United States (Florida and Louisiana) clustered with isolates from other countries. Based on the entire genome coding region, SCMV isolates infecting sugarcane in Florida were closest to virus isolates infecting sorghum species or St. Augustine grass. Virus isolates from Columbus grass, St. Augustine grass, and sugarcane showed different virulence patterns after mechanical inoculation of Columbus grass, St. Augustine grass, and sugarcane plants, thus proving that these isolates were different pathogenic strains. Sugarcane was symptomless and tested negative for SCMV by tissue blot immunoassay after inoculation with crude sap from SCMV-infected Columbus grass, indicating that Columbus grass was not a reservoir for SCMV infecting sugarcane in the EAA. Close CP sequence identity between isolates of SCMV from Columbus grass, maize, and sorghum suggested that the same virus strain was naturally spreading between these three plants in south Florida.

Effect of sunnhemp (Crotalaria juncea L.) green manuring on weed dynamics in puddle transplanted rice-based systems

Effects of Crotalaria juncea green manure on weed dynamics in transplanted rice-based systems were investigated in a field study conducted over two cropping seasons, 2016 and 2017, at Ludhiana, India. The major weed species in the field, during the green manuring phase, included Cyperus rotundus, Digitaria ciliaris and Eleusine indica. The use of cover/green manure crops and their residues to suppress weeds has shown potential to manage weeds. In this context, green manuring/cover cropping has great potential and is feasible in a rice-wheat system in northern India as there is a 45 to 60 days’ fallow period between wheat harvest and transplanting of rice. C. juncea with 50 and 100 kg seed ha-1 recorded significantly lower density and biomass of aerobics weeds and weed density as compared to without green manure in both years; GM with 100 kg seed ha-1 had a more suppressing effect on weeds than green manuring with 50 kg seed ha-1. The residual effects of weed control treatments, applied during 2016 to succeeding transplanted rice crops, did not have any specific trend on weed density in 2017. The major weeds in green manuring crop were C. rotundus, D. ciliaris and E. indica. But in transplanted rice, Echinochloa colona, E. crus-galli and Leptochloa chinensis were major weeds

Detecting the effect of ACCase-targeting herbicides on ACCase activity utilizing a malachite green colorimetric functional assay

AbstractResearch was conducted using a functional malachite green colorimetric assay to evaluate acetyl-coenzyme A carboxylase (ACCase) activity previously identified as resistant to sethoxydim and select aryloxyphenoxypropionate (FOPs) herbicides, fenoxaprop, and fluazifop. Two resistant southern crabgrass [Digitaria ciliaris (Retz.) Koeler] biotypes, R1 and R2, containing an Ile-1781-Leu amino acid substitution and previously identified as resistant to sethoxydim, pinoxaden, and fluazifop but not clethodim was utilized as the resistant chloroplastic ACCase source compared with known susceptible (S) ACCase. Dose-response studies with sethoxydim, clethodim, fluazifop-p-butyl, and pinoxaden (0.6 to 40 µM) were conducted to compare the ACCase–herbicide interactions of R1, R2, and S using the malachite green functional assay. Assay results indicated that R biotypes required more ACCase-targeting herbicides to inhibit ACCase activity compared with S. IC50 values of all four herbicides for R biotypes were consistently an order of magnitude greater than those of S. No sequencing differences in the carboxyltransferase domain was observed for R1 and R2; however, R2 IC50 values were greater across all herbicides. These results indicate the malachite green functional assay is effective in evaluating ACCase activity of R and S biotypes in the presence of ACCase-targeting herbicides, which can be used as a replacement for the 14C-based radiometric functional assays.

Impact of Invasive Alien Species- Acacia nilotica on the Remnant Dry Deciduous Forest of Palu Valley, Central Sulawesi, Indonesia

Aims: The study was carried out to assess the species composition, vegetation structure, regeneration and possible direction of vegetation development due to Acacia nilotica invasion.
 Study Design: The study applied the vegetation analysis and remote sensing technique in the deciduous forest of the Palu Valley in Central Sulawesi.
 Place and Duration of Study: The study was conducted in Biromuli District, Sigi Regency, Central Sulawesi Province of Indonesia in February 2019.
 Methodology: Species composition, vegetation structure and regeneration were studied using the split plot method, while the specific population and distribution of A. nilotica were studied using drone photos in an area of 10.24 ha.
 Results: Individuals >2cm in diameter are 24 species, 22 genera and 14 families. The main species are Tabernaemontana pandacaqui, A. nilotica and Jatropha gossypiifolia. The ground vegetation (diameter<2cm) contained 21 species, 21 genera and 17 families, dominated by Digitaria ciliaris and A. nilotica. The species diversity index is 2.3880 (moderate), while the species evenness index is 0.75 (unstable). Density of 1.069 individual’s per ha and total basal area 2.48 m2 per ha. The dominance of individuals with a diameter of 2.0-4.9 cm (62.9%), followed by diameter of 5.0-9.9 cm (32.4%), and diameter of 10 cm up (4.67%). The canopy layer consists of only one main layer at a height of 4-7m. Canopy analysis using drone photos showed that 27% of the total forest canopy area and 32.9% of the total individuals were controlled by A. nilotica.
 Conclusion: The dry forest in Sigi is the remnant deciduous forest located specifically in the Palu Valley which is still in the process of development. The invasion of A. nilotica needs to be controlled in a sustainable way so that the rest of the forest does not turn into a stretch of A. nilotica.

Phytotoxic β-resorcylic acid derivatives from the endophytic fungus Lasiodiplodia theobromae in the mangrove plant

• New β -resorcylic acid derivatives were isolated from an endophyte L . theobromae . • Absolute configuration was established using Mosher's ester analysis and chemical ECD calculations. • (3 S, 7 R )-17- O -methyl- de - O -methyllasiodiplodin showed growth inhibitory effects against D. ciliaris. Three new β -resorcylic acid derivatives, 1 – 3 , were obtained from the endophytic strain Lasiodiplodia theobromae GI-1005, which was isolated from the mangrove plant Rhizopora mucronata. The structures of new compounds together with five known compounds were elucidated by NMR and MS analyses, and chemical means. The isolated compounds were evaluated for phytotoxicity against Digitaria ciliaris (southern crabgrass) and Lactuca sativa (lettuce). Compound 1 showed growth inhibitory effects against D. ciliaris in a dose-dependent manner.

Design, synthesis, herbicidal activity, in vivo enzyme activity evaluation and molecular docking study of acylthiourea derivatives as novel acetohydroxyacid synthase inhibitor

In order to develop novel herbicides, a series of novel acylthiourea derivatives containing methylsulfone were synthesized and characterized by melting point, elemental analysis, infrared spectroscopy, mass spectrometry and 1H NMR spectroscopy. Furthermore, the preliminary herbicidal activity of title compounds was determined against Echinochloa crusgal, Polypogon fugax, Digitaria adscendens, Brassica napus, Amaranthus retroflexus and Abutilon theophrasti. The results of the petri dish experiments showed that a small part of title compounds had a good inhibitory effect on Digitaria adscendens and Brassica napus. The results of the greenhouse herbicidal activity experiments indicated that the compounds 4p, 4 w and 4x exhibited more high herbicidal activity against Brassica napus and Digitaria adscendens than the commercial herbicide bensulfuron-methyl. Moreover, except for compound 4i, all test compounds performed well in crop safety evaluation. Next, acetohydroxyacid synthase (AHAS) enzyme activity experiments were carried out, and the results showed that compound 4x had the highest inhibition rate reaching 89.12%. Finally, in order to screen AHAS inhibitor, molecular docking was performed by using AHAS protein and target ligand molecules 4a-4x. The results of molecular docking were similar to bioassay experiments. Compound 4p, 4w and 4x were considered potential AHAS inhibitors.

Synthesis, herbicidal activity, enzyme activity, and molecular docking of novel aniline thiourea

A series of new acyl thiourea derivatives containing aniline moiety were designed and synthesized. The preliminary herbicidal activity tests showed that some compounds had good herbicidal activity against Digitaria adscendens, Amaranthus retroflexus, especially for compound 4j (N-((4-chloro-3-(trifluoromethyl)phenyl)carbamothioyl)-4-(methylsulfonyl)-2-nitrobenzamide) and 4 l (N-((2-bromo-5-fluorophenyl)carbamothioyl)-4-(methylsulfonyl)-2-nitrobenzamide) . The results showed that compound 4j and 4l had an inhibition rate of 98% and 96% on the root growth of Brassica napus L. at the concentration of 100 mg L−1. Compounds 4j and 4 l had higher comparative activity on Echinochloa crusgalli than the commercial herbicide bensulfuron-methyl. The preliminary structure–activity relationship (SAR) was also summarized. We also tested the in vivo AHAS enzyme activity inhibition experiment of 17 compounds at 100 mg L−1, and the results showed that they all have inhibitory activity on the enzyme, with the highest inhibition rate reaching 43.66% (compound 4l). Based on the results of molecular docking to yeast acetohydroxyacid synthase (AHAS), the possible herbicidal activity mechanism of these compounds was evaluated.