Annual Weeds Research Articles

Exploring germination requirements of Iva xanthiifolia: Implications for potential spread in Europe

Iva xanthiifolia, an invasive annual weed species native to North American prairies, is an agricultural problem in different parts of the world and represents a health hazard as an allergen to humans. This study addresses the limited literature on its germination requirements, focusing on base temperature, base water potential, and salinity tolerance. Seeds from a Serbian population near Belgrade were tested to various conditions. The experiments were conducted using temperatures ranging from 1 °C to 30 °C and water potentials ranging from 0 to –2 MPa, while salinity tolerance was tested at three temperatures (1, 3, and 6 °C) and five salinity levels (0 to 16 dS/m). Results indicate higher germination rates at lower temperatures (1 °C) compared to higher temperatures (30 °C), with a base temperature of 0.7 ± 0.37 °C. Germination decreased with increased water potential, showing a base water potential of -1.58 ± 0.07 MPa. Salinity tolerance was observed, with germination even at 16 dS/m (the final germination rate was 54.5 % ±2.88). Additionally, germination was observed declining with increasing temperature in a saline environment. As germination is one of the major determinants of a species’ success, the possible spreading of this species under different climate change scenarios was simulated. Results of future distribution modelling suggested sensitivity to precipitation changes and potential northward expansion of this species. This research enhances our understanding of Iva xanthiifolia traits, useful for supporting management strategies for its control and mitigation of its impact, even under future climate change and land-use scenarios.

Diversity and Population of Weed Propagule in Two Rice Cropping Systems

Weeds can reduce rice yields by 20-89%, mainly due to competition for nutrients, water, sunlight, and growing space. Weeds that grow in rice fields come from propagules previously in the soil. Seedlings are formed from the previous season, so the cultivation system greatly affects them. This study aims to determine the diversity and population of weed propagules in upland rice and lowland rice. This research was conducted by survey method in Semanu District, Gunungkidul Regency, Special Region of Yogyakarta, by taking soil samples from three plots of upland rice and lowland rice paddy. Soil sampling was conducted four times before tillage, 3, 6, and 9 weeks after planting. The results showed that the diversity of weed propagules in upland rice was higher than in lowland rice fields with more weed propagule species. Annual terrestrial weed propagules dominate in upland rice, while in lowland rice fields, it is dominated by annual aquatic weed propagules. The diversity index of weed propagules in upland rice and rice paddy is included in the medium criteria. The number of species and individual propagule weeds in upland rice is more than in the upland rice fields. The results of this study can be used as a basis for proper weed management so that it does not disturb and harm rice plants.

A new Record of the Genus Carduus Curtis. (Asteraceae) for Iraq

Carduus tenuiflours Curtis is record as a new study in Iraq. This species has been collected from Al-Nahrain university and Baghdad university in Baghdad town in the middle of Iraq. The morphological characters, habitat of the species with a key to Carduus L. species in Iraq have been provided. The study showed that C. tenuiflorus a winter annual plant weed distributed in West Europe, China, India and Pakistan. Possess a broad leaves plant is similar in appearance to Italian thistle, C. pycnocephalus. Plants grow up to 100 cm tall with triangular shape stem wings that are up to 1 cm tall and are tipped with a spine. Leaves are oblanceolate to lanceolate with 6-8 pairs of spine-tipped lobes, while the inflorescence are capitulum consist of 3-10 in clusters with many series of phyllaries the inner one is longer and broader than the outer and median phyllaries with purplish tinged. The flowers purple tubular with distinct lobes about 10-12 mm long, hermaphrodite and have white pappus while the fruit is cypsela about 2.5-3.5 mm.

Influence of crop rotations and cotton monoculture on cotton field weediness

The paper proves that crop rotation and cotton monoculture turned out to be the best agro technical measures in reducing the number of weeds against the control variant which was found by the authors as a result of long-term studies of cotton crop rotations. The results of the studies showed that permanent cotton crop without and with mineral fertilizers in the absence of crop rotation contribute to a significant increase in the number of annual and perennial weeds. Development of crop rotations with strict alternation of cotton with the main predecessors in the cotton complex, as well as appropriate agro-technical measures significantly reduce the weed infestation of cotton field during the entire cotton growing season.

First Report of Powdery Mildew Caused by Golovinomyces ambrosiae on Xanthium orientale in Korea.

Xanthium orientale L. (syn. Xanthium canadense Mill., Asteraceae), known as cocklebur, is an annual weed native to North America, which is now a neophyte distributed throughout the world. This plant was accidentally introduced to Korea in the late 1970s ( So et al. 2008) and is considered a problematic exotic weed in orchards, for which many herbicides are ineffective (Kim et al. 2020). In September 2018, powdery mildew was observed on X. orientale in Jeju, Korea. The disease incidence ranged from 40 to 60%. Voucher specimens were deposited in the Korea University Herbarium (Accession No. KUS-F30795) and Kunsan National University Herbarium (KSNUH1988). Symptoms appeared as round to irregular white patches with abundant hyphal growth on the leaf surface. Hyphal appressoria were nipple-shaped, and 3 to 6 μm diam. Conidiophores (n = 30) were 145 to 206 × 9 to 11.6 µm and produced 2 to 5 immature conidia in chains with a sinuate outline. Foot-cells of the conidiophores were straight, cylindrical, and 43 to 100.9 μm long. Conidia (n = 30) were ellipsoid-ovoid, doliiform to somewhat limoniform, 25.2 to 31.8 × 13.6 to 16.8 μm (l/w 1.6 to 2.1), and devoid of distinct fibrosin bodies. The morphological characteristics corresponded to those of Golovinomyces ambrosiae (Schwein.) U. Braun & R.T.A. Cook (Braun and Cook 2012, under Golovinomyces spadiceus (Beck. & M.A. Curtis) U. Braun; Qiu et al. 2020). To confirm the identity of the causal fungus, the internal transcribed spacer (ITS), large subunit (LSU) (Bradshaw and Tobin 2020), the intergenic spacer (IGS) of rDNA, and the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene (Bradshaw et al. 2022) were amplified for a herbarium specimen (KUS-F30795). A BLASTn search of these sequences revealed 100% identity with reference sequences of G. ambrosiae on diverse Asteraceae plants (AB077644 for ITS, AB077643 for LSU, ON361171 for IGS, and ON075648 for GAPDH). However, there was a single nucleotide difference on both the IGS and GAPDH sequences when compared to the closely related species Golovinomyces latisporus. The sequences were deposited in GenBank (Accession No. OQ165157 (ITS), OQ165164 (LSU), OR050524 (IGS), and OR086076 (GAPDH)). Phylogenetic analyses of ITS, LSU, IGS, and GAPDH sequences revealed the Korean sample formed a well-supported group with other G. ambrosiae sequences, confirming its identity. A pathogenicity test was performed through inoculation by gently pressing diseased leaves onto the leaves of five healthy plants. Five non-inoculated plants served as controls. All plants were maintained in a greenhouse at 25±2°C. Powdery mildew colonies developed on the inoculated plants after ten days, whereas the control plants remained symptomless. The fungus present on the inoculated leaves was morphologically identical to that observed on the initially diseased leaves, fulfilling Koch's postulates. Powdery mildew on X. orientale has previously been reported as Golovinomyces cichoracearum (≡ Erysiphe cichoracearum) sensu lato in the USA, G. ambrosiae (= G. spadiceus) throughout all continents, and Podosphaera fusca sensu lato (now P. xanthii) in Korea (Braun and Cook 2012; Farr and Rossman 2023). To date, powdery mildew in Korea has been reported only on Xanthium strumarium as G. cichoracearum s. lat. and Podosphaera xanthii (KSPP 2022). To our knowledge, this is the first report of powdery mildew caused by G. ambrosiae on X. orientale in Korea.

Synergistic Effect of Herbals and Nanoparticles - Zinc Oxide on Silkworm Pathogens

Acalypha indica L. is an annual herbaceous weed and widely distributed throughout the tropical region of India. It has been wound healing activity, antibacterial activity and antiurolithiatic activity. The herbal plant Murrayakoenigii have been used as analgescis, astringents, antidysenterics or febrifuges in folk medicine in China and other Asian countries. The antibacterial responses of Zinc oxide (ZnO) against Staphylococcus sp. SA 3were investigated. The acetone, ethyl acetate and methanol extracts of A. indica showed minimum inhibitory activity4 ±0.31mm, 10±0.18 mm and 6±0.23 mm respectively and maximum inhibitory activity 8±0.15 mm, 20±0.37 mm and 12±0.14mm at different concentration (0.5, 1.0, 1.5 and 2.0 µl) against the bacterial pathogen Staphylococcus sp. SA 3. The acetone and methanol extracts of M. koenigii showed minimum inhibitory activity 6±0.25 mm and 6±0.25 mm and maximum inhibitory activity 10± 0.18 mm and 8±0.15 mm. The ethyl acetate extract of M. koenigii did not showed inhibitory activity. In the combined effect of acetone, ethyl acetate and methanol extracts of A. indica and ZnO showed minimum inhibitory activity 4±0.31 mm, 10±0.13 mm and 4±0.31 mm respectively and maximum inhibitory activity 10± 0.13 mm, 22± 0.30 mm and 8±0.15 mm respectively. The combined effect of acetone, ethyl acetate and methanol extracts of M. koenigii and ZnO showed minimum inhibitory activity 16±0.08 mm and 6± 0.23 mm. The ethyl acetate extract of M. koenigii showed no inhibitory activity and maximum inhibitory 20± 0.37 mm, 2± 0.04 mm and 10± 0.13 mm respectively. The GC-MS analysis of methanol extract of A. indica showed the presence of 8 phytoconstituents and the nanoparticle ZnO impregnated ethyl acetate extract of A. indica showed the presence of 11 phytoconstituents.

Enhancing Sugar Beet (Beta vulgaris L.) Yield and Quality: Evaluating the Efficiency of Chemical and Mechanical Weed Control Strategies

Weeds exert a pronounced influence on the sugar beet yield, leading to the potential for substantial reductions in agricultural productivity. In pursuit of addressing this issue, two experiments were conducted at the Faculty of Agriculture in Giza, Egypt, during the winter seasons of 2020/2021 and 2021/2022 to investigate the efficacy of various pre- and post-herbicides applied differently in active ingredient percentages, forms, and on weed target types, and mechanical weed treatments on weed traits and sugar beet crop performance. (1) In this context, five herbicidal treatments, including pre-emergence (S-Metoachlor) and post-emergence applications of Betanal Max Pro (Desmedipham 4.7% + Ethofumesate 7.5% + Lenacil 2.7% + Phenmedipham 6%), Tegrospecial (Desmedipham 20% + Phenmedipham 20%) for total annual weeds, C Factor (Haloxyfop-R-Methyl 7.5% + Fluazifop-p-putyl 15%), and Clictar (Clethodium 24%) for grassy weeds, were assessed alongside mechanical weeding and a weedy check (control). (2) The evaluations encompassed growth parameters, juice quality, and beet yields to comprehensively assess the treatment effects. (3) Notably, weed control measures, especially regarding three total annual weeds herbicides and the cultivation when using both grassy weed herbicides, consistently produced the highest improvements in sugar beet root’s fresh and dry weights, root dimensions, sucrose content, purity, sugar recovery, as well as the root and recoverable sugar yields, across both seasons. (4) However, it is important to note that the application of Clethodium 24% and Haloxyfop-R-Methyl 7.5% + Fluazifop-p-putyl 15% resulted in elevated levels of sodium, potassium, amino nitrogen, impurities, and sucrose loss to molasses. These findings underscore the substantial influence of herbicide use and mechanical weeding on sugar beet’s growth, juice quality, and yield, with S-Metoachlor, Desmedipham 20% + Phenmedipham 20% and Desmedipham 4.7% + Ethofumesate 7.5% + Lenacil 2.7% + Phenmedipham 6%—showing promise as effective weed control options, albeit with certain associated drawbacks.

Influence of environmental factors on seed germination and seedling emergence of Amaranthus blitoides S. Watson and A. hybridus L.

AbstractAmaranthus blitoides S. Watson and A. hybridus L. are common herbaceous annual summer weeds in different regions of Iran, which produce a large number of small seeds per plant. The goal of these experiments was to determine seed germination cardinal temperature and investigate the effect of constant temperature, osmotic and salt stresses, stratification, flooding duration, after‐ripening and seed planting depth on seed germination and seedling emergence. Two‐piece segmented, dent‐like and beta four‐parameter models were used to investigate the relationship between germination rate and constant temperature. The dent‐like model showed the best description of the effect of constant temperature on seed germination rate of both A. blitoides and A. hybridus. Optimal seed germination of A. blitoides occurred at 35°C, but in A. hybridus optimum germination was observed in a range of constant temperatures from 30 to 40°C. Osmotic and salt stresses and flooding adversely affected seed germination of both species. After ripening for 6 months increased germination percentage of both A. blitoides and A. hybridus. Maximum seedling emergence of A. blitoides (42.8%) and A. hybridus (44.9%) occurred at a planting depth of 3.3 cm, whereas further increased planting depth minimized seedling emergence of both weeds. Information obtained from this study will help us to develop effective techniques for management of A. blitoides and A. hybridus.

Effects nursery media on Irvingia gabonensis and Dacryodes edulis seedlings and weed dynamics of the media

A field experiment was conducted to assess the effect of different nursery media on performances of Bush mango (Irvingia gabonensis) and African pear (Dacryodes edulis) seedlings. Five nursery media were formulated from topsoil, poultry manure and river sand in the following ratios; 0:3:3, 1:2:3, 1:3:2, 2:3:1 and 3:2:1. The media formulated were analyzed for the physico-chemical properties and seeds of the test crops were sown in each filled polythene bags with the formulated media. The experiment was arranged in a completely randomized design (CRD). The results obtained show significant (P≤0.05) media effects on days to first and 50% seedling emergence and percentage total emergence in Bush mango but non-significant in African pear. Number of days to last seedling emergence was significantly (P≤0.05) influenced by media in African pear leaf number and plant height for 10 weeks were responsive to differences in media in both crops. Media influenced total dry weight only in Bush mango while dry matter distribution pattern varied significantly in African pear. In both crops, percentage total seedling emergence and seedling vigour were better in medium 1:2:3. Therefore, from the results, the differential influence of media on seedling growth as evidence in the study suggested the need for broader evaluation of media for different tropical tree species to identify the most appropriate medium for each species that will ensure better vigorous seedling production for plantation and/or orchard establishment. Also, the results showed significant variation in weed flora composition, comprised of 35 species made up of 14 families. The families of Asteraceae, Gramineae, Amaranthaceae and Acanthaceae were predominant. Annual weed species and broadleaf were predominant.

Expression of Acetyl Coa Carboxylase Gene from Cleome Viscosa L. and Its Seed Oil

Asian spider flower (Cleome viscosa L.) is annual herbaceous weed plant. Its seed oil has similar properties to the seed oil from Jatropha curcas L. which is the biodiesel plant. This research focused on the expression of acetyl CoA carboxylase gene in 4 stages of seeds (1-4 weeks after fruit set (WAF)) by Reverse transcriptase Polymerase Chain Reaction (RT-PCR). Acetyl CoA carboxylase (ACCase) is the essential enzyme for the first step in the biosynthesis of long-chain fatty and glycerol. The heteromeric ACCase consists of 4 subunits. accA, accB and accC gene were located in nuclear, while the accD gene was in chloroplast. The result showed that the expression of accA gene showed the most highly expressed in 3 WAF, while the expression of accC and accD showed the most highly expression in 2-3 WAF. These results indicated that co-expression of accA, accC and accD were highest in 3 WAF and down regulated in 4 WAF. In contrast, accB gene showed the high expression level in 4 weeks after fruit set. The total oil was obtained by petroleum ether soxhlet extraction. The high oil content was 3-4 WAF. These findings suggested that comparatively high expression of the Accase gene related to the persistence of oil accumulation during the late stage of seed oil formation for C. viscosa L.

Invasion by Cenchrus spinifex changes the soil microbial community structure in a sandy grassland ecosystem

Continuous nitrogen deposition increases the nitrogen content of terrestrial ecosystems and alters the soil nitrogen cycling process. Invasive plants have strong environmental adaptability, which can not only affect the composition and diversity of soil microbial community but also significantly affect the transformation process of soil nitrogen, leading to successful invasion. Currently, research on invasive plant soil ecosystems mainly focused on changes in soil nutrients and soil microorganisms. As an invasive annual grass weed with strong ecological adaptability, the impact of Cenchrus spinifex at different growth periods on soil environment and soil microbial structure composition and diversity in sandy grassland ecosystems is still unclear. In this study, soil samples were collected from four habitats with different degrees of invasion in situ during the vegetation and reproductive growth periods of Cenchrus spinifex. High-throughput sequencing and qPCR technology were used to analyze the changes in the composition, structure and diversity characteristics of the soil microbial communities during Cenchrus spinifex invasion. The results indicated that Cenchrus spinifex invasion had different effects on the soil environment at different growth periods, and Cenchrus spinifex had a preference for the utilization of ammonium nitrogen during vegetation growth period. Moreover, Cenchrus spinifex invasion significantly changed the composition and structure of soil bacterial communities, and the response of soil bacterial and fungal communities to the invasion was inconsistent. Additionally, the bacterial network was more stable than the fungal network. At different growth periods, Cenchrus spinifex had a significant impact on the key microbial communities of soil nitrogen cycling. The invasion increased the abundance of nifH and AOA-amoA, while decreased the abundance of AOA-amoB. Alkaline hydrolyzed nitrogen, total nitrogen and total phosphorus content were key factors that affect vegetation growth period and change the key microbial communities of nitrogen cycling. Alkaline hydrolyzed nitrogen, total phosphorus and organic carbon were key factors in reproductive growth period that alter the nitrogen cycling of key microbial communities.

Propyrisulfuron plus cyhalofop butyl as one-shot herbicides provide high weed control efficiency and net economic performance in mechanically transplanted rice.

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

Mitochondrial and Proteasome Dysfunction Occurs in the Hearts of Mice Treated with Triazine Herbicide Prometryn.

Prometryn is a methylthio-s-triazine herbicide used to control the growth of annual broadleaf and grass weeds in many cultivated plants. Significant traces of prometryn are documented in the environment, mainly in waters, soil, and plants used for human and domestic consumption. Previous studies have shown that triazine herbicides have carcinogenic potential in humans. However, there is limited information about the effects of prometryn on the cardiac system in the literature, or the mechanisms and signaling pathways underlying any potential cytotoxic effects are not known. It is important to understand the possible effects of exogenous compounds such as prometryn on the heart. To determine the mechanisms and signaling pathways affected by prometryn (185 mg/kg every 48 h for seven days), we performed proteomic profiling of male mice heart with quantitative liquid chromatography-tandem mass spectrometry (LC-MS/MS) using ten-plex tandem mass tag (TMT) labeling. The data suggest that several major pathways, including energy metabolism, protein degradation, fatty acid metabolism, calcium signaling, and antioxidant defense system were altered in the hearts of prometryn-treated mice. Proteasome and immunoproteasome activity assays and expression levels showed proteasome dysfunction in the hearts of prometryn-treated mice. The results suggest that prometryn induced changes in mitochondrial function and various signaling pathways within the heart, particularly affecting stress-related responses.

Effect of Class Act NG Adjuvant on Glyphosate Efficacy in Corn

There is little information on the effect of the co-application of glyphosate with Class Act NG adjuvant on weed control efficacy and corn yield under Ontario environmental conditions. This study consisted of 6 field experiments that were conducted in Ontario during 2021 and 2022 to determine if the addition of Class Act NG (2.5% v/v) to glyphosate at 450, 900 and 1350 g ae ha-1 would improve weed control and result in a concomitant increase in corn yield. The co-application of glyphosate with Class Act NG resulted in no visible corn injury at 1 and 4 weeks after herbicide application (WAA). The addition of Class Act NG to glyphosate at 450 g ae ha-1 improved control of common lambsquarters, velvetleaf, Powell amaranth, common ragweed, and barnyardgrass as much as 20, 14, 9, 8, and 7%, respectively but there was no improvement in control of giant foxtail, or green foxtail and there was no increase in corn yield. The addition of Class Act NG to glyphosate at 900 g ae ha-1 improved common lambsquarters control 6 and 5% at 4 and 8 WAA, respectively and improved barnyardgrass control 4% at 4 WAA. The addition of Class Act NG to glyphosate at 1350 g ae ha-1 provided no improvement in control of velvetleaf, Powell amaranth, common ragweed, common lambsquarters, barnyardgrass, giant foxtail, or green foxtail and there was no increase in corn yield. Based on this data the co-application of glyphosate with Class Act NG results in improved control of some annual broadleaf and grass weeds (common lambsquarters, velvetleaf, Powell amaranth, common ragweed and barnyardgrass) when glyphosate is applied at 450 or 900 g ae ha-1; however, when glyphosate is applied at 1350 g ae ha-1 there was no improvement in weed control. The addition of Class Act NG to glyphosate at 450, 900 and 1350 g ae ha-1 did not result in an increase in corn yield.

Effectiveness of graminicide application in chickpea crops in the Eastern Forest-Steppe of Ukraine

Goal. To determine the effect of herbicides, in particular graminicides with different active ingredients, on the weediness of crops and the yield of chickpea seeds in the conditions of the Eastern Forest-Steppe of Ukraine.
 Methods. Field, measuring and weighing, statistical.
 Results. Under conditions of the Eastern Forest-Steppe of Ukraine, 27 species of weed plants were found in chickpea crops (annual cereals — 3 species, annual dicots — 17 species, perennial dicotyledonous — 7 species). Annual cereal weeds dominated in number (76.4%), and annual dicot weeds (44.3%) in terms of raw mass. The highest technical efficiency against annual cereal weeds, when applied during the budding stage of chickpea, was provided by the graminicide Lemur, EC (hyzalofop-P-tefuryl, 40 g/ l) — 1.5 l/ ha (by the number and raw mass of cereals, 99.2 and 98.3%, respectively), and the lowest efficiency was provided by the graminicide Selenite, EC (clethodim, 120 g/ l) — 1.0 l/ ha (79.4 and 71.8%, respectively). Tank mixture of soil herbicides Panda, EC (pendimethalin, 330 g/ l) — 3.5 l/ ha + Steals, EC (flurochloridone, 250 g/ l) — 2.0 l/ ha, which was applied in the pre-emergence period, controlled only the number of annual dicot weeds (technical efficiency was 62.1—79.0%), which was associated with a number of factors (the presence of resistant weed species in the crops, different soil moisture during the application period by years, the use of the minimum recommended doses of herbicides). The studied herbicides did not affect perennial dicot weeds. Combining soil herbicides with graminicides reduced the total number of weeds by 73.2—87.9%, and their raw weight by 22.4—43.0%. The highest economic efficiency (0.28 t/ ha) was provided by the composition of the preparations Panda, EC — 3.5 l/ ha + Steals, EC — 2.0 l/ ha (tank mixture) + Queen Star Max, EC (hyzalofop-P-ethyl, 125 g/ l) — 0.8 l/ ha.
 Conclusions. In the absence of the effect of the studied herbicides on perennial dicot weeds and the insufficient effect of soil herbicides on annual dicot species, despite the high effectiveness of graminicides against cereals, it was not possible to obtain significant increase in the yield of chickpea seeds (from 0.13 to 0.28 t/ ha).

Metabolomic and transcriptomic analyses of rice plant interaction with invasive weed Leptochloa chinensis.

Leptochloa chinensis is an annual weed in paddy fields, which can engage in competition with rice, leading to a severe yield reduction. However, theunderlying mechanism governing this interaction remain unknown. In this study, we investigated the mutual inhibition between rice and the weed undermono-culture and co-culture conditions. We found that the root exudates of both species played essential roles in mediating the mutual inhibition. Further metabolomic analysis identified a significant number of differential metabolites. These metabolites were predominantly enriched in the phenylpropanoid and flavonoid biosynthesis pathways in weed and rice. Transcriptomic analysis revealed that the differentially expressed genes responding to the interaction were also enriched in these pathways. Phenylpropanoid and flavonoid biosynthesis pathways are associated with allelopathy, indicating their pivotal role in the response of rice-weed mutual inhibition. Our findings shed light on the conserved molecular responses of rice and L. chinensis during theirinteraction, provide evidence to dissect the mechanisms underlying the allelopathic interaction and offer potential strategies for weed management in rice paddies.

Prickly Sida (Sida spinosa L.) and Cotton Response to Pre- and Early Post-Emergence Herbicides

Prickly sida is a troublesome annual weed native to the USA. It was introduced in Greece over two decades ago and has since been infesting cotton crops, where it proved difficult to control. A two-year field study (2021–2022) was conducted in a cotton field (Karditsa, central Greece) heavily infested with prickly sida to evaluate the efficacy of nine treatments against this weed, using pre-emergence (PRE) and early post-emergence (EPOST) herbicides applied at the field rate. At 8 weeks after treatment, prickly sida control was over 90% with pyrithiobac PRE (68.9 g ai ha−1) alone or in mixture with s-metolachlor (960 g ai ha−1) or with isoxaben (150 g ai ha−1) and with the application of pyrithiobac + s-metolachlor PRE (34.5 + 960 g ai ha−1) followed by pyrithiobac EPOST (34.5 g ai ha−1). Flurochloridone + fluometuron PRE (375 + 2000 g ai ha−1), flumioxazin + s-metolachlor PRE (50 + 960 g ai ha−1), or pendimethalin + terbuthylazine PRE (1500 + 750 g ai ha−1) controlled prickly sida by 89–93% in 2021 and 82–90% in 2022. Pyrithiobac EPOST alone or in mixture with trifloxysulfuron did not adequately control prickly sida. Yield was significantly lower in the weedy check and EPOST compared with the PRE treatments. None of the herbicides caused any visual injury to the crop or any reduction in cotton density. Our results can help in the successful management of prickly sida in non-transgenic cotton to maximize cotton yield and quality.

Alternative Integrated Weed Management Options for Clopyralid-Resistant Common Ragweed

Common ragweed (Ambrosia artemisiifolia L.) is an extremely competitive broadleaved summer annual weed found in Christmas tree production systems within Michigan. Common ragweed has been reported to have resistance to glyphosate, PSII inhibitors, PPO inhibitors, and ALS herbicides. There have been reports from Michigan Christmas tree growers of common ragweed resistance to clopyralid, a synthetic auxin herbicide, in Montcalm County, Michigan. The objective of this study was to test alternative post-emergence herbicide combinations and organic mulch on clopyralid-resistant common ragweed for weed control efficacy. The following two stages of common ragweed were used: stage 1 (6–9 leaves) and stage 2 (12–14 leaves). For common ragweed in stage 1 in 2021 and 2022, as well as stage 2 in 2022, at all evaluation dates, mulch + clopyralid + oxyfluorfen provided the highest level of weed control. For stage 1 in 2022, this treatment combination provided 100% control from 2 weeks after treatment (WAT) and always showed better or equal weed control compared to all the other treatments. The combination of mulch + clopyralid + glyphosate provided 100% control by 2 WAT when plants were treated at stage 2 in 2022. For the plants treated at stage 1 in 2022, many of the treatments reached a fresh weight of 0 g, but in 2021, those same treatments resulted in a fresh weight of around 20 g. Based on fresh weight, the greatest plant growth occurred with glyphosate treatment in 2021 and clopyralid and mulch alone in 2022. This is likely due to common ragweed’s resistance to these herbicides.

Optimizing herbicide doses for weed control in winter wheat (Triticum aestivum L.) in the Moscow region of Russia

One of the main reasons for the reduction of winter wheat yields in Russia, as in most major wheat-producing countries, is the massive infestation and rapid spread of annual weed species. Thus, this study was conducted during 2022 at D.N. Pryanishnikov Russian Research Institute of Agro chemistry, Russia with main objective to optimize the concentration of broad-spectrum herbicides: Lintur, VDG (659 g/kg dicamba-sodium + 41 g/kg triasulfuron), Bucephalus, KE (480g/L carfentrazone-ethyl), Camaro SE (6. 25 g/L florasulam + 300 g/L 2,4-D), Prima Forte 195 SE (180g/L 2,4-D + 10g/L aminopyralid +5g/L florasulam), and their plant growth regulator mixtures Moddus, KE (250 g/L trinexapac-ethyl) to protect winter wheat crops from weeds at Barbino (Russia). An inventory conducted on the study plot showed that the total number reached 434 pants/m2 weeds, with a total of 9 weed species namely Cirsium arvense, Cardaria draba, Galium aparine, Matricaria discoidea, Chenopodium album, Polygonum aviculare, Galeopsis tetrahit, Capsella bursa-pastoris, and Sinapis arvensis of which 73.9% are annual species with a vegetative cycle parallel to that of winter wheat. Herbicide application at 50% showed little difference in weed control efficacy (%) compared to standards and ranged from 56.0 to 100.0% depending on treatment and weed species. Both individually applied herbicides and their mixtures with Moddus and free weed control contributed to a significant increase in yield and the increase was from 12.3 to 23.7%. Yield when using the options mixture with the growth regulator Moddus was higher than the individual application of herbicides regardless of the dose. Yield at a dose of 50% was slightly higher or lower compared with the manufacturer's standard. In general, the growth regulator did not affect herbicide efficacy, but its combination with herbicides improved yield structure elements and increased yield quality of winter wheat.

Chemical Composition of Essential Oils from Eight Tunisian Eucalyptus Species and Their Antifungal and Herbicidal Activities.

Eucalyptus species are known to produce metabolites such as essential oils (EOs) that play an important role in the control of weeds, pests and phytopathogenic fungi. The aims of this study were as follows: (i) to determine the chemical composition of the EOs derived from eight Eucalyptus species growing in Tunisia, and (ii) to study their possible antifungal and herbicidal activities. EOs were obtained by hydrodistillation from the dried leaves of eight Eucalyptus species, namely, E. angulosa, E. cladocalyx, E. diversicolor, E. microcoryx, E. ovata, E. resinifera, E. saligna and E. sargentii, and the determination of their composition was achieved by GC and GC-MS. The EOs' antifungal activities were tested against four Fusarium strains, and the EOs' herbicidal properties were evaluated on the germination and seedling growth of three annual weeds (Trifolium campestre, Lolium rigidum and Sinapis arvensis) and three cultivated crop species (Lepidium sativum, Raphanus sativus and Triticum durum). The EO yields ranged between 0.12 and 1.32%. The most abundant components found were eucalyptol, α-pinene, p-cymene, trans-pinocarveol, α-terpineol and globulol. All EOs showed significant antifungal activity against the four phytopathogenic Fusarium strains. E. cladocalyx EO exhibited the highest level of antifungal activity, and the greatest inhibition of seed germination was obtained even at lowest concentrations used. These findings suggested that E. resinifera, E. ovata and E. cladocalyx EOs could have applications in agriculture as possible biopesticides, as Fusarium antagonists and as bioherbicides.