ABSTRACT Targeted application technologies combine imaging systems for weed detection with single nozzle control for herbicide application. The potential of herbicide saving using targeted application is very high because weeds are usually distributed heterogeneously in agricultural fields. This study presents a real‐time system for single weed plant control in maize. The targeted application technology is integrated in a conventional 36 m wide boom sprayer. Ten field experiments were conducted in maize, five in 2023 and five in 2024. Two experimental sites were in East‐Germany, two in Southwest‐Germany and one in Hungary. All experiments included an untreated control, a broadcast herbicide application and a targeted application. Identical herbicides were used in both application systems. The embedded imaging processing unit segmented the plants from the soil and calculated the weed coverage (%). If weed coverage was higher than 0%, the spray nozzle was activated and one spot treatment applied. Targeted application was realised at a driving speed of 10 km h −1 . Weed control efficacy (%) (WCE) was calculated based on weed density counts before and 14 days after herbicide application. Targeted application achieved on average 25% herbicide savings in both years ranging from 2% to –73%. Targeted application achieved 72%–99% WCE. Maize yield and WCE did not differ between broadcast and targeted application in any of the 10 experiments. This study shows that targeted application technology can be integrated into large conventional boom‐sprayers without hindering the herbicide application and performance. Further savings could be realised if the imaging system would classify between different weed species, economic weed threshold would be applied and spray nozzles covering less area would be used.

ABSTRACT Although numerous studies have examined reproductive strategies in weedy species, many have overlooked the influence of plant size on resource allocation patterns. Resource investment in Cyperus esculentus , measured as allocation to sexual structures and clonal propagules (tubers), was assessed at the genet level in a potted experiment under two contrasting light‐availability conditions, using three clonal populations from northeastern Argentina. It was found that shading consistently reduces both sexual and clonal reproduction, along with declines in genet size, while the relative investment in leaf mass remains invariant. Both sexual and clonal mass are strongly dependent on genet size under shade, where resource availability for growth is limited. Under full sun, no evidence appears for a linear relationship between genet size and either sexual or tuber mass; nevertheless, the reallocation of resources and meristems towards clonal expansion (i.e., the production of new ramets) may influence both reproductive functions. No association is evident between reproductive allocation plasticity across populations and fitness traits (represented by sexual and clonal mass); differences in reproduction among populations arise from variation in vegetative size rather than allocation strategy. A minimum genet size is required for both sexual reproduction and tuber production. Although no significant phenotypic correlation is found between sexual and clonal allocations, the negative relationship between sexual allocation and mean tuber size suggests that a trade‐off exists between the two reproductive functions. A thorough understanding of size‐dependent reproductive relationships in Cyperus esculentus has significant implications for its control and preventive management.

ABSTRACT Grasses in the Poaceae family are major components of global ecosystems and agricultural systems, and their adaptive success has enabled some species to become highly competitive weeds. Digitaria insularis (sourgrass), a C4 perennial grass native to the Americas and now widely introduced elsewhere, has evolved herbicide resistance and poses an increasing threat to crop productivity. This study modelled the current and future climatic suitability of D. insularis using ecological niche models under two climate change scenarios (SSP126 and SSP585) for 2030 and 2090. After filtering 1329 occurrence records, 559 high‐confidence records were used for modelling. A total of 19 bioclimatic variables from WorldClim were reduced via Principal Component Analysis, and four algorithms (Bioclim, Maxent, Random Forest, and SVM) were combined into an ensemble approach. Model performance was consistently high across metrics, and MOP analyses indicated limited strict extrapolation, supporting the robustness of projections. Results show extensive suitability across tropical and subtropical regions under current conditions, with substantial retention of suitable areas and progressive gains in future scenarios. Expansion was particularly pronounced under SSP585, with increased suitability in South America, Sub‐Saharan Africa, Southeast Asia, northern Australia, and higher‐latitude agricultural regions, including the U.S. Corn Belt and Mediterranean Europe. These expansions overlap with structurally vulnerable agricultural systems, indicating an elevated risk of invasive spread and potential impacts on food security. The findings highlight the need for proactive, integrated, and cross‐regional management strategies to mitigate future spread and resistance‐related agronomic losses.

ABSTRACT Adjuvants are widely employed to enhance herbicide performance, offering both economic and environmental benefits in weed management programmes. While most research has focused on surfactants, nitrogen‐based adjuvants, such as ammonium compounds, combined with herbicides like tribenuron‐methyl, also show promising potential. In a pot experiment conducted during 2021–2022, Sinapis arvensis (wild mustard) was used as the testing plant to evaluate the synergistic effects of various surfactants and ammonium sources, both individually and in combination, on the efficacy of tribenuron‐methyl. Treatments consisted of tribenuron‐methyl at 0, 0.3, 0.6 and 1.0 times the recommended rate (equivalent to 0, 4.5, 9 and 15 g a.i. ha −1 ), applied either alone or in combination with surfactants (castor oil ethoxylate [COE], lauryl alcohol ethoxylate [LAE], cocamidopropyl betaine [CPB] and sodium lauryl ether sulphate [SLES], all applied at 1 L ha −1 ) and ammonium sources (ammonium nitrate, ammonium sulphate and ammonium acetate, each at 1% [w/v], plus asparagine at 0.1% [w/v]). While surfactants and ammonium sources each independently enhanced herbicide efficiency, their combined application had a more pronounced effect, as evidenced by a greater number of treatments achieving significant reductions in effective doses. The simultaneous application of ammonium acetate with LAE or SLES reduced ED 90 to 6 g a.i. ha −1 . Additionally, compared to adjuvant‐free control, co‐applying asparagine amino acid with SLES or ammonium acetate with CPB lowered ED 90 values from 15 to 7.10 and 7.70 g a.i. ha −1 , respectively.

ABSTRACT The success of invasive species like Ageratina adenophora is frequently related to their functional trait advantages and ecological flexibility. Hence, this study evaluated the morphological trait‐based performance of A. adenophora in relation to its co‐occurring herbaceous species across four sites in the Champawat district of the Kumaun Himalaya, representing two forest types: Banlekh (site 1), dominated by Quercus leucotrichophora , and Chowki (site 2), Gauri (site 3), and Shaktipur (site 4), which are characterised by Cedrus deodara forests. Four species, that is, Ajuga parviflora , Apluda mutica , Cyperus rotundus , and Erigeron karvinskianus , were chosen from Banlekh, from Chowki, Anaphalis busua from Gauri, and, A. parviflora , Anaphalis busua , and Viola canescens , were chosen from Shaktipur for the comparison based on their association and growth with A. adenophora . Plant morphological and leaf traits were assessed during January, 2025 across all these four sites following standard methods. The results showed that A. adenophora steadily unveiled the highest population density, peaking at Shaktipur (88.65 individuals/m 2 ) and Chowki (80.12 individuals/m 2 ), far surpassing nearby species such as A. parviflora (11.5 ind./m 2 ) and C. rotundus (33.33 ind./m 2 ). Morphologically, A. adenophora reached maximum shoot length (23.05 cm in Shaktipur), plant height (90.77 cm), and stem volume (13.28 cm 3 in Banlekh), often exceeding neighbouring herbs by 30%–90%. It also maintained longer roots (66.05 cm in Banlekh), with values up to 99.2% greater than co‐occurring species in Shaktipur. A. adenophora demonstrated higher specific leaf area (up to 1177.96 cm 2 /g at Gauri), superior stem mass fraction (up to 61.62%), and a higher root: shoot ratio (up to 0.83), reflecting an avaricious resource use approach. Leaf biomass was also higher (e.g., 2.57 g in Chowki, 53.33% more than A. busua ) significantly, and above and belowground biomass values commonly topped those of co‐occurring species by over 90%, especially in Banlekh and Chowki. In spite of infrequent trait setbacks in Shaktipur, A. adenophora demonstrated steady inexpensive dominance. These results confirm that both superior trait values and phenotypic plasticity contribute to the prevalent invasion of A. adenophora . This study underscores the importance of trait‐based assessments for understanding invasion dynamics and supervisory targeted biological management.

Abstract The objective of this study was to characterise multiple resistance to glyphosate and acetyl‐CoA carboxylase (ACCase)‐inhibiting herbicides from an Argentine population of Sorghum halepense (Johnsongrass) (GC‐R). Whole plant dose response trials with haloxyfop‐p‐methyl revealed that the GC‐R population was highly resistant, with LD50 and GR50 values exceeding eight times the recommended field dose (64.8 g ai ha−1). Sequence analysis identified three unique ACCase mutations in GC‐R: Ile2041Asn and Ala2096Gly, and a novel mutation, Ile1699Thr. Dose–response experiments were performed with three different clones selected by PCR‐based markers. The clone carrying Ile2041Asn + Ile1699Thr (GC‐4) showed the highest LD50 (>2074 g ai ha−1), while the clone carrying Gly2096Ala (GC‐6) and the clone carrying Gly2096Ala + Ile1699Thr (GC‐7) showed similar LD50 (1241 and 1021 g ai ha−1, respectively). Glyphosate dose–response showed LD50 slightly above 1X (1494 g ai ha−1), but biomass was significantly reduced (GR50 = 715 g ai ha−1). Molecular analysis ruled out mutations in the 5‐enolpyruvylshikimate‐3‐phosphate synthase (EPSPS) sequence and gene amplification. The two known ACCase substitutions conferred high levels of resistance to haloxyfop‐p‐methyl, consistent with previous reported inhibition patterns. The newly found mutation could be involved in the resistance phenotype, although its contribution is unclear. Glyphosate resistance likely involves a non‐target site resistance mechanism (NTSR).

Abstract Ryegrass species (Lolium spp.) are both cultivated crops and troublesome weeds. Weedy ryegrasses are prone to evolve herbicide resistance and are particularly widespread in regions of intense ryegrass propagation, like Saxony in Germany and the Pacific Northwest in the USA. In such cases, pre‐emergence herbicides become key control measures. Therefore, 39 German weedy ryegrass populations, which survived herbicide applications in the field, were assessed for their species, ploidy and resistance to three different herbicide modes of action (MoAs). Additionally, 34 commercial cultivars of the Festuca–Lolium complex were screened for resistance, followed by target gene sequencing of surviving individuals. Resistance was widespread among weedy ryegrass populations, with 77% exhibiting resistance to acetyl‐CoA carboxylase (ACCase) inhibitors, 59% to acetolactate synthase (ALS) inhibitors and 18% to very‐long‐chain fatty acid (VLCFA) biosynthesis inhibitors. Resistance was confirmed in two ryegrass cultivars: A L. perenne cultivar exhibited resistance to flufenacet (VLCFA inhibitor) biosynthesis and to ALS and ACCase inhibitors due to single‐nucleotide polymorphisms (SNPs). SNPs in the ACCase gene were furthermore found in a tetraploid L. hybridum cultivar. Despite the prevalence of tetraploid varieties, most weedy ryegrasses were diploid L. multiflorum. Nevertheless, the occurrence of tetraploid weedy ryegrass confirms that cultivars can become weeds. In conclusion, herbicide‐resistant diploid L. multiflorum dominated among weedy ryegrass populations. Diploid populations establish more easily as weeds and possibly evolve resistance faster. Furthermore, unidentified resistance in ryegrass cultivars can be a source of weed resistance. Therefore, preventing flowering and seed shattering, particularly of diploid ryegrass cultivars, is crucial under field conditions.

Abstract The increasing reliance on acetolactate synthase (ALS)‐inhibiting herbicides alone has resulted in the evolution of resistance in key broad‐leaf species in cereal farms in Ireland. Our objective was to confirm and characterise the resistance levels and mechanisms in resistance‐suspect populations (R) of Stellaria media (STEME‐R1, STEME‐R2 and STEME‐R3), Papaver rhoeas (PAPRH‐R), Glebionis segetum (GLESE‐R) and Veronica persica (VERPE‐R) to two different ALS‐inhibiting herbicide chemistries, sulfonylurea (SU) and triazolopyrimidine (TP). Following single‐dose testing that confirmed inadequate control of all six R populations, dose–response experiments revealed varying resistance levels to SU and/or TP, which were associated with target‐site resistance mutations. Weed species populations, STEME‐R1 and STEME‐R3 (both Trp‐574‐Leu), and STEME‐R2 (combined Trp‐574‐Leu and Pro‐197‐Ser; first report for this species), and PAPRH‐R (Trp‐574‐Leu, which was detected for the first time in all population plants, combined with Pro‐197‐His or Pro‐197‐Leu) and VERPE‐R (Trp‐574‐Leu; first worldwide case) showed high resistance or cross‐resistance to SU and TP. All herbicide‐surviving plants tested were heterozygous for single or combined mutations. The G. segetum population, GLESE‐R, had multiple substitutions and zygosity (Pro/Leu, Leu, Leu/Gln or Thr/Leu) at Pro‐197, which was identified for the first time for this species conferred SU resistance only. Cytochrome P450 inhibitor studies on selected species did not detect metabolism‐mediated resistance to SU or TP. Alternative herbicide modes of action alone or in co‐formulation with ALS‐TP should be used to manage these resistant populations. This study has added new information to the current knowledge of the resistance spectrum to ALS inhibitors in several broad‐leaved weeds.