Carrots are a challenging crop to produce because the plants are slow to emerge and their early growth limits their tolerance to biotic and abiotic stresses, including those imposed by mechanical cultivation. In field studies conducted in Holt, Michigan, in 2021 and 2022, we evaluated the effects of carrot seed grading and using a sequence of in-row mechanical cultivation methods on carrot survival, weed mortality, and yield. We tested two key hypotheses: 1) carrots grown from large seed size fractions (LS carrots) would have greater root anchorage force and height than those grown from small seed size fractions (SS carrots) and hence greater tolerance to uprooting and burial imposed by finger weeders (FW) and hilling disks (HD); and 2) alternating in-row cultivation tools with these mechanisms of action (HD-FW) would reduce carrot mortality and improve weed management efficacy relative to continued use of a single tool (FW-FW). At the time of the first cultivation, LS carrots had greater anchorage force and height than SS carrots in both years, and greater tolerance to cultivation (lower mortality) in one of two years. The HD-FW cultivation sequence provided improved weed control efficacy and carrot yield than the FW-FW sequence in one of two years. However, when cultivation occurred early, the ability of the tools to kill weeds without killing or injuring crops was low regardless of seed size, and all treatments required supplemental hand weeding. When crops were cultivated later, no differences in carrot mortality based on seed size were detected. LS carrots exhibited a 17% to 23% increase in yield compared with SS carrots, regardless of the cultivation tool used. These results suggest that more intensive seed grading coupled with cultivation tools and settings that target weed burial can enhance profitability of carrot production.

Adoption of early-planted soybean requires investigating optimal residual herbicide programs to ensure effective season-long weed control and crop safety. Experiments were conducted at three locations in Indiana in 2024 and 2025 to evaluate the interaction of soybean planting dates (early, early-mid, mid-late, and late) and soil residual herbicides applied at a full rate, a reduced rate (2/3 of full rate), and no rate on soybean stand, yield, and weed control. Early planting resulted in slightly more soybean injury (5% to 10%) from residual herbicides than later planting dates but that did not translate into yield loss. Soybean stand was typically lower (by 13% to 23%) when the crop was planted early, but this did not reduce soybean yield, except in one site-year when drastically lower temperatures after planting caused a 35% stand reduction in early planted soybean compared with late-planted, resulting in a 15% yield reduction. Early planting dates resulted in at least up to 21% higher canopy coverage early in the season compared with later planting dates. Early planting resulted in a 2.5-fold, 1.9-fold, and 2.4-fold increase in common lambsquarters, giant ragweed, and waterhemp density, respectively, at postemergence compared with late planting, which resulted in greater selection pressure for herbicide-resistant weed biotypes with postemergence herbicides. An early planting date resulted in a greater yield than when the crop was planted both mid-late and late at all site-years, except one, in 2024. The inclusion of residual herbicides at any soybean planting date, at either full or reduced rates, did not cause yield reductions compared with applying no residual herbicides.

A comprehensive assessment of herbicide resistance in waterhemp accessions to herbicides commonly used on corn and soybean over time is crucially necessary for documenting shifts in herbicide resistance patterns and identifying effective management options. Therefore, a greenhouse study was conducted to evaluate the response of statewide waterhemp accessions collected in 2023 to commonly used preemergence and postemergence herbicides and to assess changes in resistance over a 5-yr period by comparing these results with previous statewide data from 2018. One hundred percent, After a postemergence application of atrazine, 2,4-D, dicamba, fomesafen, and mesotrione at 1× rates, 100%, 88%, 83%, 41%, and 24%, respectively, of 2023 accessions exhibited ≥50% survival. Glufosinate provided complete control, with 0% survival and ≥97% biomass reduction among all accessions. The 1× rate of mesotrione, metribuzin, and S-metolachlor applied preemergence resulted in >95% density reduction in all accessions. The 1× rate of atrazine and fomesafen resulted in <90% density reduction in 50% and 82% of accessions, respectively. The 2023 accessions exhibited a significant increase in survival when several postemergence herbicides were applied at the 1× rate, including 2,4-D (from 11% to 52%), dicamba (from 8% to 49%), atrazine (from 11% to 81%), fomesafen (from 3% to 21%), and mesotrione (from 2% to 11%), compared with the 2018 accessions. Similarly, a change in waterhemp density reduction was observed between the 2018 and 2023 accessions when preemergence herbicides were applied, including atrazine (from 84% to 91%), fomesafen (from 97% to 81%), and S-metolachlor (from 98% to 95%). No changes were observed in the density reduction of the 2018 and 2023 accessions in response to mesotrione and metribuzin at the 1× and 3× rates. The rapid adaptation herbicide resistance within 5 yr by waterhemp highlights the urgent need to incorporate effective integrated weed management strategies in Wisconsin cropping systems.

Timothy is the primary forage grass seed crop in Norway, and thus effective control of dicot weeds and lodging management are critical steps in maximizing timothy seed yield and meeting seed purity standards. Optimal timing of gibberellic acid–inhibiting plant growth regulators (PGRs), such as chlormequat chloride (CCC) and trinexapac-ethyl (TE), often coincides with spring herbicide applications, raising concerns about crop safety and herbicide efficacy when products are tank-mixed. Field experiments were conducted in 2022 and 2023 at two locations in Norway to evaluate the effect of mixing PGRs with commonly used herbicides on timothy lodging, seed yield, and seed quality. Plant growth regulators (1,500 g ai ha⁻1 CCC and 150 g ai ha⁻1 TE) were applied either separately (herbicides at BBCH stage 25; PGRs at BBCH stage 35) or tank-mixed (at BBCH stages 30 to 35) with one of three herbicide combinations: fluroxypyr + florasulam, florasulam + diflufenican, or aminopyralid + 2,4-D + florasulam. Seed yield was affected by PGR treatments (P ≤ 0.05) but not by herbicide treatments. Plant height and lodging were reduced more with TE than with CCC; however, relative yield responses varied with timothy stand age. Tank mixing both products did not reduce seed yield or herbicide efficacy. Crop injury from tank mixtures was minimal and temporary, and no reductions in final seed germination were observed. Tank-mixing CCC and TE PGRs with herbicides maintained optimal seed yield and quality, offering operational flexibility for timothy seed producers.

North Carolina farmers face mounting challenges in controlling Italian ryegrass, as herbicide-resistant populations continue to be found in more fields across the state. Increased selection pressure has led to cases of multiple and cross resistance to herbicides, leaving growers with fewer options for effective weed control. The objective of this study was to understand the Italian ryegrass frequency and distribution of resistance to commonly used postemergence herbicides with various sites of action. Italian ryegrass seedheads were collected from throughout North Carolina in June 2022. A statewide grid sample resulted in 115 samples being collected from wheat fields with observed Italian ryegrass escapes. Seeds were germinated in greenhouses, and herbicides were applied to 4-leaf plants. Treatments included a nontreated check, and applications of glufosinate, glyphosate, mesosulfuron, paraquat, and pinoxaden, all at 1× rates according to each product label. Populations controlled ≤50% by a specific herbicide were considered to have putative resistant. Forty-four populations were found to exhibit putative resistance to glufosinate, 17 to pinoxaden, 10 to mesosulfuron, 2 to glyphosate, and 1 to paraquat. One population with four-way resistance and two with three-way resistance were found. The results from this collection were compared with populations from a similar statewide collection conducted in 2012. These populations were screened for response to diclofop, mesosulfuron, pinoxaden, and pyroxsulam. We also screened these populations for response to glufosinate, glyphosate, and paraquat. Out of 102 populations, none were found to be resistant to glyphosate and paraquat, while 91 were determined to exhibit resistance to glufosinate. These results are helpful for growers and Extension personnel as they develop effective weed management programs.

Small-scale vegetable farmers rely on hand tools for weed management, including wheel hoes, stirrup hoes, and tine rakes. They also pull weeds by hand in crop rows, with costs increasing in proportion to weed density. The Terrateck double-wheel hoe offers improved efficiency by straddling the crop row and weeding both sides. We evaluated the effects of single tools and tool combinations or (stacking) with the Terrateck double-wheel hoe, measuring weed control efficacy and crop mortality. In 2 yr of field experiments, six single tools and all possible two- and three-tool combinations were tested. Tools included biodiscs, finger weeders, tine harrows, L-sweeps, precidiscs, and torsion weeders. Bush bean and table beet were used as test crops. Tool stacking improved weed control efficacy over single tools, but average benefits were modest, with gains of 12% and 13% over single tools in bush bean and table beet, respectively. Regression analysis and observation of treatment rankings indicated that L-sweeps were a critical tool for top-performing treatments. In bush bean, for example, four tool combinations with L-sweeps had an average efficacy of 69% ± 15% compared with 37% ± 11% efficacy for all other treatments. The combination of L-sweeps, tine harrows, and torsion weeders provided the greatest weed control efficacy in both bush bean and table beet. Tool stacking did not affect bush bean mortality, which ranged from 0.9 to 2.0 plants killed per 1.5 m of row. However, in one experiment, stacking increased table beet mortality from 4.1 plants per 1.5 m of row for single tools, to 6.9 plants per 1.5 m of row for combinations with two tools. Overall, the Terrateck double-wheel hoe provides small-scale farmers an opportunity to improve efficiency and, with the ability to stack tools, improve weed control efficacy.

Nissan Chemical Corporation and Gowan USA are currently developing iptriazopyrid, a novel herbicide that inhibits 4-hydroxyphenylpyruvate dioxygenase (HPPD), for weed control in rice. Field experiments were conducted near Crowley, Louisiana, to evaluate iptriazopyrid mixed with common auxin herbicides used in Louisiana rice production. Iptriazopyrid was applied at a reduced rate of the proposed 1 × label rate to determine possible compatibility issues. The study was organized as a randomized complete block with a two-factor factorial arrangement of treatments, and treatments were applied at 94 L ha−1 post-flood. Factor A consisted of either no iptriazopyrid or iptriazopyrid applied at 50 g ai ha−1, whereas factor B included each auxin herbicide. Across all evaluation intervals, barnyardgrass was controlled by 68% to 80%, whereas broadleaf signalgrass was controlled by 27% to 31% when iptriazopyrid was applied alone. Iptriazopyrid alone controlled barnyardgrass by 80% 35 d after treatment, compared with 29% and 43% when iptriazopyrid was mixed with triclopyr or 2,4-D, respectively. Mixtures of iptriazopyrid with triclopyr and 2,4-D resulted in antagonism for barnyardgrass, while only the iptriazopyrid and 2,4-D mixture was antagonistic for broadleaf signalgrass control. The mixture of iptriazopyrid with quinclorac indicated a neutral interaction for both grasses while an antagonistic interaction was observed for alligatorweed control. Iptriazopyrid mixed with florpyrauxifen resulted in a neutral interaction across all weed species evaluated and proved to be the most compatible mixing partner among the auxin herbicides within these studies. The results of these studies indicate that iptriazopyrid should not be mixed with triclopyr or 2,4-D when targeting barnyardgrass. To prevent antagonistic interactions split applications or alternative mixture partners should be considered. Supplemental research is needed to determine whether antagonism is rate dependent and whether increasing the rate of iptriazopyrid to the 1 × labeled rate will overcome the antagonism.

Emerging targeted herbicide application technologies, such as the ONE SMART SPRAY system (a joint venture of Bosch, Gerlingen, Germany; and BASF Corporation, Research Triangle Park, NC), enable postemergence herbicide application only where weeds are detected. Field studies were conducted in 4 site-years in Seymour, Illinois, and Janesville, Wisconsin, during 2023 and 2024 to compare area treated and waterhemp control between broadcast and targeted herbicide applications to soybean. Early postemergence application of herbicides to soybean at the V2 growth stage at the Seymour location in 2023 resulted in less area treated (26%) than when herbicides were applied at the standard time (76%) but required inclusion of a layered residual herbicide to reach 89% to 93% waterhemp control and biomass reduction ≥94% at 28 d after the standard application time (DASAT). The standard herbicide application time (the V4 growth stage of soybean) at the Seymour location in 2023 provided 87% to 97% waterhemp control and ≥94% biomass reduction at 28 DASAT. In 2 site-years, when waterhemp densities were low (≤5 plants m−2), treatments provided >96% waterhemp control and biomass reduction at 28 DASAT, and targeted applications resulted in 17% to 34% area treated, regardless of application time. In contrast, at Janesville in 2024 (high waterhemp density, >30 plants m−2), waterhemp control and biomass reduction did not exceed 90% at 28 DASAT, but the area treated was ≥97% at postemergence application, indicating that targeted spraying essentially functioned as a broadcast application and would have required additional postemergence applications for effective season-long control. Under high waterhemp densities, frequent nozzle activation reduced potential herbicide savings and diminished differences from broadcast applications, clearly indicating that targeted herbicide application systems are best suited for fields where effective foundational management practices, including robust preemergence herbicide applications and other integrated weed management tactics, reduce weed density during postemergence application season.

A mineral ecological cropping system (MECS) that uses mineral fertilizers but no synthetic pesticides has been tested in field trials in Germany over 6 yr. Uncertainty persists over whether mineral nitrogen favors crops or weeds under MECS, and this issue was examined in a greenhouse pot study. The study investigated how corn and spring barley and selected weed species (common lambsquarters and barnyardgrass for corn; blackgrass and common chickweed for spring barley) responded to mineral nitrogen. The experiment included crop:weed combinations of 1:0, 1:2, 1:5, and 0:1 for corn, and 1:0, 1:5, 1:15, and 0:1 for spring barley, representing two monocultures, evaluated under four nitrogen doses (0N, ½N, 1N, and 2N). Data on root and shoot development of weeds and crops were determined at harvest. Increasing the dose of nitrogen increased the biomass of both corn and weeds, while weeds benefited more from the higher nitrogen doses than corn. Competitiveness of spring barley against weeds varied with increasing nitrogen doses. Blackgrass benefited more from higher nitrogen levels than spring barley, while common chickweed was better suppressed by spring barley when nitrogen levels were high. Weed:crop biomass ratios confirmed the observed shifts in competitive balance. The results highlight the importance of effective multitactic weed control in MECS.

Herbicide-resistant Palmer amaranth has been problematic within the United States for the past 30 yr. The recent introduction of Palmer amaranth into the Pacific Northwest (PNW) prompted extensive surveys in 2023 and 2024 to collect seed samples for herbicide-resistance screening and leaf tissue for resistance-mechanism genotyping. Greenhouse dose-response bioassays were conducted in Kimberly, Idaho, during summer 2024 to assess the response of Palmer amaranth populations to selected postemergence herbicides. Resistance to glyphosate predominated across populations, and reduced sensitivity to 2,4-D, dicamba, and mesotrione was also observed. In contrast, glufosinate and saflufenacil provided effective control of Palmer amaranth populations in the PNW. Based on the dose-response bioassays, the effective dose required to provide 90% control (ED90) of the suspected glyphosate-resistant populations was 20-fold to 63-fold compared with the susceptible population. Subsequent duplication analysis of the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene was conducted to confirm glyphosate resistance in the Palmer amaranth populations. About 74% (17 of 23) of the Palmer amaranth tissue samples exhibited gene duplication, with up to 150 copies of the EPSPS gene. The EPSPS gene amplification analysis of plants that survived a 2× rate of glyphosate (2,520 g ae ha−1) showed up to 150 EPSPS genes in glyphosate-resistant populations. The widespread glyphosate resistance in the collected samples suggests that Palmer amaranth populations are being introduced into the PNW from locations where resistance to herbicide sites of action has previously evolved.

Field studies were conducted in 2020 and 2021 near Crowley, Louisiana, to evaluate florpyrauxifen-benzyl applied at 0, 7.3, 14.6, 21.9, and 29.2 g ai ha−1 coated onto the surface of urea fertilizer or as a postflood spray for residual control of ducksalad. All studies were conducted on a Crowley silt loam (fine smectic, thermic Typic Albaqualfs), pH 6.5, and with 2.3% organic matter. Square plots were 1.5 × 1.5 m−2. Each plot contained a plastic ring 53 cm in diameter and 30 cm deep. At 70 d after treatment (DAT), ducksalad emergence did not exceed 23% when florpyrauxifen-benzyl was applied via surface-coated urea, compared with 98% to 99% emergence following postflood spray applications. By 56 DAT, more than 93% of ducksalad treated with florpyrauxifen-benzyl as a postflood spray, regardless of rate, had reached the petiolate leaf stage. However, ducksalad treated with florpyrauxifen-benzyl as a surface-coated urea application resulted in 3% to 18% petiolate leaf development at 56 DAT. Similar to ducksalad emergence and petiolate leaf development, applying florpyrauxifen-benzyl coated onto the surface of a urea prill reduced ducksalad flowering compared with postflood spray applications. This reduction in flowering throughout the growing season could reduce seed production and potentially impact future ducksalad infestations. Findings suggest florpyrauxifen-benzyl applied via surface-coated urea is more effective at reducing ducksalad emergence, petiolate leaf development, flowering, and fresh weight biomass compared with being applied as a postflood spray. Overall, applications of florpyrauxifen-benzyl applied via surface-coated urea reach the soil surface rapidly, increasing growth inhibition of ducksalad and possibly other germinating weed species.

Alfalfa establishment failure has been reported in fields where corn was grown the previous season. Herbicide mixtures of clopyralid, mesotrione, acetochlor, and/or flumetsulam have been implicated as a potential factor. To address this, experiments were conducted to assess the effects of these residual herbicides on alfalfa establishment and biomass production following a corn crop. Clopyralid, mesotrione, acetochlor, and flumetsulam were applied to corn at the V4 stage either alone or mixed with other active ingredients found in two commercial herbicide premixes (clopyralid + acetochlor + mesotrione and clopyralid + acetochlor + flumetsulam) at two locations and compared with a nontreated control. Soil was collected in November just prior to soil freezing and a greenhouse bioassay evaluated establishment and productivity of three alfalfa cultivars. Alfalfa was then planted the following spring into fields and evaluated for establishment and resulting productivity. Greenhouse results found that locations and cultivars behaved differently to the herbicide treatments. Alfalfa aboveground biomass was reduced by 24% to 38% with applications of mesotrione and flumetsulam and the premix of clopyralid + acetochlor + flumetsulam. Belowground biomass increased when flumetsulam alone was present and in the premix that contained mesotrione. A field bioassay did not discern any differences in stand establishment or aboveground biomass. While reductions in alfalfa establishment and resulting productivity the year following application were not confirmed, the differences in the fall suggest that the potential exists if adequate breakdown does not occur over the winter/spring.

Farmers in the U.S. Midwest are increasingly planting soybean earlier in the growing season, which is prompting an investigation of which herbicide programs are most effective for achieving season-long weed control. The use of overlapping residual herbicides involves applying a full rate of a soil-residual herbicide preemergence, followed by an early postemergence application of a residual herbicide before the next flush of weeds emerge. Field experiments conducted in 2024 and 2025 at three locations in Indiana evaluated the interaction between soybean planting date and herbicide programs on season-long weed control, soybean stand, and grain yield. Soybean planting date factor included early (March to May) or late (May to June) planting dates, and herbicide programs factor included overlapping residuals followed by non-residual postemergence applications (Overlapping fb NRPOST), preemergence followed by NR POST (PRE fb NR POST), and POST only programs. Early planting resulted in 7% to 25% lower soybean stand, whereas herbicide program had minimal effect on soybean stand. Crop injury from residual herbicides was minimal with both early and late planting dates (≤5%). Compared to late planting, early planting resulted in 44% greater common lambsquarters density at POST herbicide application and 66% and 44% greater biomass at soybean harvest of common lambsquarters and giant ragweed, respectively. In giant ragweed-infested fields under early planting, the POST only herbicide program, which included soil residual and foliar-active herbicides, resulted in at least 34% lower yield than the Overlapping fb NR POST and PRE fb POST programs. In contrast, under late planting, soybean yield did not differ among herbicide programs.

Cutleaf evening primrose, a member of the Onagraceae family and native to the southeastern United States, is found in agricultural fields, nursery crops, roadsides, landscaped areas, and no-till production systems. Cutleaf evening primrose management has become increasingly difficult due to its ability to endure control measures beyond the rosette stage. Greenhouse trials were conducted during the 2025 growing season to assess the efficacy of labeled burndown herbicides for cutleaf evening primrose control. Field-collected cutleaf evening primrose seedlings were transplanted into pots and placed in a greenhouse for evaluation at two growth stages. The recommended herbicide rates (at 1×) tested were glyphosate at 1,260 g ae ha−1, glufosinate at 672 g ai ha−1, 2,4-D at 1,065 g ae ha−1, paraquat at 840 g ai ha−1, and glyphosate + 2,4-D, respectively. Herbicides were sprayed at late rosette and bolting growth stages. Control of cutleaf evening primrose was evaluated at 7, 14, 21, and 28 d after herbicide treatments (DAT). Shoot dry biomass data were collected at 28 DAT. Application of 2,4-D either alone or mixed with glyphosate resulted in 98% to 100% control at both growth stages. Depending on the growth stage at which herbicides were applied, cutleaf evening primrose was controlled 66% to 75% with glyphosate, 60% to 81% with glufosinate, and <25% with paraquat. The highest dry biomass reductions (≥80%) were observed with glyphosate, 2,4-D, and glyphosate + 2,4-D applications at the rosette stage. The study revealed that 2,4-D-alone or with glyphosate provided near-complete control of cutleaf evening primrose.

Pyridate, a photosystem II–inhibiting herbicide used since the 1980s on corn, cereal, and sorghum crops, shows promise for controlling weeds of turfgrass; however, whether it is safe to use it on turfgrass species remains untested. This study evaluated pyridate’s effects on visible injury, green cover, and dark green color index (DGCI) for eight weekly assessments on seven turfgrass species, including hybrid bermudagrass, creeping bentgrass, fine fescue, Kentucky bluegrass, perennial ryegrass, tall fescue, and zoysiagrass. Fourteen field experiments were conducted in 2024 using a randomized complete block design with four replications, testing pyridate at 350, 700, and 1,400 g ae ha−1 alone or combined with sulfentrazone (280 or 560 g ae ha−1). Results showed significant injury at 7 d after treatment (DAT) to all turf species (P ≤ 0.0163), peaking at 35% for bermudagrass with the high pyridate–sulfentrazone mix under warm, moist conditions, but dissipating by 14 DAT. Green cover decreased most (52%) with the high mix in Trial 2 with bermudagrass, while plots treated with pyridate at ≤700 g ha−1 matched that of nontreated cover. The DGCI mirrored injury trends, with minimal impact from pyridate at 350 g ha−1. Pyridate’s safety aligns with its metabolic detoxification by grasses, unlike broadleaf plants, while sulfentrazone exacerbated damage, which is consistent with prior turfgrass studies. At ≤700 g ha−1, pyridate proved to be safe to all species, suggesting its potential use for selective weed control in turfgrass systems. Higher rates or sulfentrazone mixes require caution due to transient injury to favorable plants. Further research should optimize application conditions and target turfgrass weeds to refine pyridate’s role in integrated management amid rising herbicide resistance in turfgrass systems.

Italian ryegrass is a significant weed in Oregon, and resistance to multiple herbicide sites of action is widespread. Nonchemical tools are needed to improve management of Italian ryegrass in orchard systems. Field studies were conducted in Oregon to evaluate electrical weed control (EWC) of Italian ryegrass at two voltage ranges (3.9 kV and >5.0 kV) and multiple energy rates generated by varying travel speed. Energy was the primary factor affecting EWC efficacy. Control increased with increasing operational energy rate and, in two studies conducted when Italian ryegrass was at tillering to stem elongation stages, visible estimates of control reached 70% to 80% at 67.5 to 168.8 kJ m−2, corresponding to travel speeds of 0.8 to 0.32 km h−1. Control was lower in a third study when plants were at a more advanced growth stage. Plant density was not consistently reduced, indicating that a single EWC application suppressed growth but did not consistently kill Italian ryegrass plants. When energy was increased shoot and inflorescence dry weight and inflorescence number were reduced, indicating lower reproductive output among surviving plants. Voltage effects were limited and inconsistent across studies. These results indicate that EWC can suppress herbicide-resistant Italian ryegrass and reduce reproductive output in orchard systems, but a single treatment does not provide complete control. Growers will likely need to repeatedly apply EWC or to integrate it with other weed control tactics to improve suppression and reduce reproductive output.

Managed turfgrass covers approximately 16.4 million ha in the United States and generates substantial economic value while providing recreational and ecosystem benefits in urban landscapes. Integrated weed management (IWM) is essential for sustainable turfgrass systems, but its implementation differs markedly from IWM in row-crop production because of distinct management objectives, available tactics, and state and federal regulations. Annual row-crop systems focus on yield optimization, while perennial turfgrass swards prioritize aesthetics, playability, and public safety. Turfgrass management relies heavily on cultural practices (species and cultivar selection, mowing, fertility, irrigation) and the use of chemicals because other strategies that apply to row-crop production, such as cover crops, crop rotation, and tillage, have limited applicability. This review synthesizes current knowledge of turfgrass IWM components, including cultural, physical (e.g., fraise mowing, laser, thermal), biological (e.g., bioherbicides, insects), and chemical (e.g., herbicides, plant growth regulators, organic alternatives, targeted application technologies), and contrasts them with IWM in row-crop production. We further examine federal regulations that affect the management of herbicide-resistant weeds, with particular emphasis on drivers of human health risks and measures to mitigate risks to species listed under the Endangered Species Act (ESA). While managing herbicide resistance is a primary concern in both systems, turfgrass managers face higher per-hectare weed management costs, stricter public-exposure protections, and additional regulatory restrictions. Current ESA mitigation measures are largely based on row-crop models and may overlook turfgrass-specific attributes that reduce environmental exposure risk. Key challenges include limited geospatial data to help characterize turfgrass use sites and inadequate recognition of existing turfgrass management practices as effective mitigation measures, including continuous vegetative cover, no-till, irrigation management, reduced application rates, and precision or spot applications. This review highlights the need for turfgrass-specific research, development, and validation of IWM efforts that integrate emerging technologies chemical and nonchemical tactics, including an assessment of their long-term ecological and economic effects, and for aligning them with regulatory policy to support effective weed management in turfgrass systems.

Mechanical cultivation can entail the use of more than one type of weed control implement in the same pass. Implements may even be synergistically “stacked” to maximize efficacy. However, in previous trials, stacked setups have caused unacceptable damage to crops. In this study, several changes were made to previously used cultivation setups, including adding GPS guidance, using sweeps rather than torsion weeders, and spacing the implements farther from the crop. In test crops of snap bean and beet, stacked three-tool combinations resulted in greater weed-control efficacy with no significant decrease in the survival of well-established crops, thereby providing improved selectivity. Few differences were found among one-, two-, or three-tool categories, except that the harrow-type implements were often less aggressive than the other tools. Combining all our trials, the crop to weed height ratio appeared to be a main driver of intrarow cultivation success, but stacking still provided a benefit. Specifically, to achieve successful cultivation with 80% weed control and 5% or less crop mortality, we modeled that one-, two-, and three-tool combinations required crop-to–weed height ratios of at least 6.2, 5.6, and 3.6, respectively. Based on these trials, farmers may improve their cultivation selectivity by creating conditions in which their crops are as large as possible relative to weeds and by using precisely guided, stacked cultivation implements adjusted to minimize contact with crops.