Growers have increasingly adopted the planting of cover crops as a sustainable way to control problematic and herbicide-resistant weeds. Understanding the critical period of crop-weed competition is essential for timely and effective weed management tactics in cropping systems. A 2-yr field experiment was conducted in Alabama to evaluate the effect of a cover crop mixture that included cereal rye, crimson clover, and hairy vetch, and a planting of cereal rye alone on the critical period for weed control (CPWC) in soybean. The experiment was implemented in a split-plot design in which the main plots were cover crop mixture, cereal rye, and winter fallow, and subplots were five durations of weed-free and weed-interference plots. The presence of planting a cover crop mixture and cereal rye delayed the critical timing for weed removal (CTWR) by approximately 2 wk compared with winter fallow. Results in 2019 showed the predicted duration of CPWC following cover crop mixture, cereal rye, and winter fallow was 4.8 wk, 0 wk, and 5.1 wk, respectively. Furthermore, in 2020, the estimated CPWC duration following plantings of a cover crop mixture or cereal rye versus a winter fallow was 1.4 wk, 0.1 wk, and 2.6 wk, respectively. In both years, the plantings of single-species cereal rye resulted in the shortest CPWC due to its early-season weed suppression, while winter fallow plots demonstrated the longest CPWC duration. In conclusion, a shorter duration of CPWC with the incorporation of cover crops could help soybean growers enhance their weed control efforts and provide greater yield protection to soybean.

Producers who grow strawberries in plasticulture and who intend to maintain the strawberry plants into a second harvest season find that stolons (runners) are undesirable because they produce daughter plants that divert resources from the mother plant and complicate field maintenance. Removing runners by hand is labor-intensive and becomes more challenging once daughter plants have rooted in the row middles. Napropamide and pendimethalin were evaluated in greenhouse studies to assess their potential to suppress daughter plant rooting and facilitate runner removal. Greenhouse studies used a three-pot experimental unit consisting of one strawberry mother plant with two runners, each bearing one unrooted daughter plant, and two side pots simulating row middles. Three treatments were evaluated, including broadcast (foliar + side pot spray), in‑row (foliar spray only), and row‑middle (side pot spray only) herbicide applications, and were compared against a nontreated control. On mother plants, napropamide caused transient foliar injury but did not affect runner production or biomass. On daughter plants, napropamide caused transient injury and suppressed new growth at 4 wk after treatment (WAT), reducing daughter plant biomass by 59% to 68%. Napropamide also eliminated the pull force required for removal relative to the nontreated control and reduced aboveground and belowground biomass by up to 49% and by >95%, respectively, demonstrating effective suppression of runner establishment by reducing daughter plant rooting. However, suppression was transient; by 8 WAT, only the broadcast treatment consistently maintained rooting inhibition, likely due to herbicide degradation over time. Pendimethalin caused no effects on mother plants or daughter plants under any application method and failed to inhibit daughter plant rooting entirely. These results suggest that napropamide applied to the row middles, the only label-compliant method evaluated, can effectively suppress daughter plant rooting for at least 1 mo, providing growers with a supplementary benefit of eased runner removal during summer weed management.

Glufosinate is a key postemergence herbicide in U.S. soybean production, particularly where resistance to glyphosate and inhibitors of acetolactate synthase is widespread. A 25-question survey of soybean growers, agronomists, and industry professionals in Arkansas and Wisconsin was conducted in Fall 2022 to characterize glufosinate use patterns, weed management challenges, and stakeholder perceptions. Palmer amaranth was reported as the most problematic weed in Arkansas (97% of respondents), and waterhemp was most frequently reported in Wisconsin (92%). Suspected glyphosate resistance was widely reported (97% in Arkansas, 88% in Wisconsin), and suspected glufosinate resistance was reported by 37% of Arkansas respondents and by 3% of Wisconsin respondents. Eighty-four percent of Arkansas respondents reported integrating glufosinate into their weed management programs, as did 53% of Wisconsin respondents, and most respondents said they used it to target broadleaf weeds ≤15 cm tall. Carrier volumes were 103 to 140 L ha−1 (chosen by 75% of Arkansas respondents), and 150 to 187 L ha−1 (chosen by 86% of respondents from Wisconsin). Arkansas respondents most frequently reported using glufosinate in sequential first and second postemergence applications (62%). In Wisconsin, glufosinate use was reported mostly only as a first postemergence application (37%), followed closely by sequential use in the first and second postemergence applications (34%). Weed size, followed by carrier volume and air temperature, were ranked as the most important factors affecting glufosinate performance. Ammonium sulfate was the most used adjuvant (45% in Arkansas; 67% in Wisconsin), and spray water quality was rarely tested. Frequently reported tank-mix partners included glyphosate and inhibitors of protoporphyrinogen oxidase in Arkansas and synthetic auxins and clethodim in Wisconsin. Extension efforts should emphasize applying glufosinate to small weeds (<10 cm in height), optimizing application technology and spray solution characteristics (nozzle, carrier volume, water quality/adjuvant selection), and spraying under favorable environmental conditions. Improving application consistency can reduce weed escapes and repeat postemergence applications, thereby lowering selection pressure and preserving glufosinate as an important postemergence option.

The prevalence of Palmer amaranth weeds that are resistant to inhibitors of glyphosate and acetolactate synthase has been affecting sugar beet yield in Colorado and Nebraska since 2020. While metamitron applied preemergence has previously been reported to effectively control glyphosate-resistant Palmer amaranth, the rates evaluated in the literature are likely higher than what is practical for growers to use on their crops. Consequently, identifying an optimal rate will reduce potential herbicide use while still effectively controlling Palmer amaranth. Lower rates of metamitron may be sufficient to allow control of Palmer amaranth through the two true-leaf (2 TL) stage of growth, when herbicides that inhibit very-long-chain fatty acids can be used to layer additional residual herbicides and prevent Palmer amaranth emergence. Multiple dose–response analysis studies were established in Nebraska in 2020 and 2023, and in Colorado in 2023, to determine the necessary rate of metamitron, with and without a tank-mix partner of ethofumesate, to control Palmer amaranth through the 2 TL stage of sugar beet. Metamitron rates ranged from 0 to 6.40 kg ai ha−1, while ethofumesate was included at a fixed rate of 1.68 and 1.86 kg ai ha−1 in 2020 and 2023, respectively. At all locations, maximum Palmer amaranth control was obtained when metamitron (4 kg ai ha−1) was applied alone. Adding ethofumesate as a tank-mix partner reduced the metamitron use rate to about 2.9 kg ai ha−1. Results of these trials provided supporting evidence for the U.S. Environmental Potection Agency to issue an emergency exemption under Section 18 of the Federal Insecticide, Fungicide, and Rodenticide Act to use metamitron at a rate of 3.27 kg ai ha−1 in Colorado and Nebraska in 2024, and the subsequent extension to include Idaho, Oregon, and Wyoming in 2025.

Nonchemical weed management is essential for advancing integrated weed management systems. Mid infrared (MIR) radiation (3 to 50 µm) is a promising approach for heat-based thermal weed control with minimal fire risk. The lethal MIR energy requirement may be influenced by plant species, growth stage, and seed size. However, no published research has quantified the MIR energy dose (J cm−2) needed to control either weed seeds or various plant species at different growth stages. This study evaluated a dose range of 0 to 109 J cm−2 to identify MIR energy thresholds required to control six species at the 3-, 6-, and 9-leaf growth stages, as well as dry and imbibed seeds of nine species. Responses were described using regression models based on dry biomass, survival, and reductions in viability. Overall responses varied across species, with smaller broadleaf weeds being most susceptible. Palmer amaranth was highly sensitive, requiring 13 and 57 J cm−2 to reduce biomass by 90% at the 3- and 6-leaf stages, respectively, while Italian ryegrass was highly tolerant, with 109 J cm−2 failing to achieve a 90% biomass reduction. Across all species, plants at the 9-leaf stage were highly tolerant, with no treatment achieving a 90% reduction. Dry Palmer amaranth seeds were the most tolerant, requiring 100 J cm−2 to reduce viability by 50%, compared with 8 J cm−2 for imbibed seeds. Conversely, dry barnyardgrass seeds were more susceptible, requiring just 16 J cm−2 for 50% viability reduction compared with 31 J cm−2 when imbibed. Seed size was moderately and positively correlated with the energy required for 50% viability reduction (r = 0.58). This study provides evidence that MIR radiation can serve as an effective thermal weed control tool, while also highlighting that efficacy varies among species, likely due to differences in plant morphology and physiology.

Over the years, the rapid and widespread spread of weeds across international borders has become a major threat to agriculture and native ecosystems. Seeds of invasive species are often transported via commodity trade, making rapid and accurate identification essential. This review aims to explore current practices at plant quarantine centers worldwide for detecting weed seeds and to examine potential molecular techniques that could revolutionize this process in the future. Book chapters, scholarly research articles, conference proceedings, and previously published literature on weed seed detection approaches and plant quarantine inspections in various countries were reviewed, examined, and compared to identify the tools and techniques currently used or potentially developed. The literature survey revealed that countries employ diverse strategies for issuing phytosanitary certificates for import and export commodities, adhering to agreements established by global and regional plant protection organizations. Both traditional morphology-based techniques and advanced molecular tools were identified in these practices. Weed seeds present particular detection challenges at quarantine ports, including physiological dormancy that undermines germination-based tests, morphological similarity to crop seeds, and zero-tolerance phytosanitary thresholds for certain noxious species. The review identified various deviations and advanced methods for detecting weed seeds in import and export commodities, aiming to determine the most appropriate or suitable technique for plant quarantine services in worldwide.

Fraise mowing is a turfgrass cultivation practice used to mechanically control annual bluegrass via a combination of physical removal and seedbank depletion. Research was conducted to determine whether fraise mowing could restore the efficacy of annual bluegrass control herbicides lost due to resistance. Herbicide treatments were applied to plots within separate fraise-mowed and non-fraise–mowed experiments conducted on a hybrid bermudagrass golf course fairway infested with annual bluegrass that became resistant to herbicides from Groups 2, 3, 5, and 29. Fraise mowing was performed on June 18, 2024, and June 23, 2025, to a 1.3-cm depth. Herbicides tested included diquat dibromide, flumioxazin, foramsulfuron, glufosinate, glyphosate, indaziflam, metribuzin, oxadiazon, prodiamine, pronamide, simazine, tetflupyrolimet, and thiencarbazone + foramsulfuron + halosulfuron. Herbicides were applied according to label directions at preemergence, early postemergence, mid-postemergence, or late postemergence timings during 2024 to 2026. In the fraise-mowed experiment, indaziflam, tetflupyrolimet, prodiamine, pronamide, simazine, and metribuzin provided 86% to 100% control of annual bluegrass by 12 wk after initial treatment (WAIT) and 61% to 88% by 24 WAIT. Without fraise mowing, these herbicides provided ≤53% and ≤73% control at 24 WAIT in 2024 and 2025, respectively. Increased efficacy may be related to a reduction in the annual bluegrass seedbank from fraise mowing because the practice reduced plant counts in nontreated check plots by 75% to 88% each year. Applications of diquat dibromide and flumioxazin mid-postemergence provided 18% to 34% control of annual bluegrass at 6 WAIT in the fraise-mowed experiment; whereas these same herbicides provided ≤10% control when they were applied to non-fraise–mowed hybrid bermudagrass. Mid-postemergence applications of glufosinate and glyphosate and late postemergence applications of foramsulfuron and thiencarbazone + foramsulfuron + halosulfuron performed similarly in both experiments. Restored use of residual herbicides lost due to resistance may remove barriers to adopting the practice of fraise mowing for annual bluegrass control.

Cotton and soybean with tolerance to 2,4-D, glufosinate, and glyphosate offer useful options for managing herbicide-resistant weeds, especially Palmer amaranth, but effective late-season weed management depends on herbicide program design and timing. In 2019 and 2020, field experiments at two North Carolina locations compared herbicide programs built on preemergence herbicides (fomesafen + acetochlor), followed by an early postemergence application of glufosinate and/or a late postemergence application of 2,4-D + glyphosate. Control was assessed at 7 to 8 wk after planting, and yields were standardized within environment to the maximum observed yield to allow direct comparison of herbicide programs across crops. Overall, treatments that included a herbicide applied late postemergence (preemergence+ late postemergence, early postemergence + late postemergence, or preemergence + early postemergence + late postemergence) provided complete control of weeds and prevented yield losses. Herbicides applied preemergence + early postemergence frequently provided a slightly lower control than late postemergence herbicide applications, and a preemergence herbicide applied alone consistently resulted in the lowest control. Lower early season rain in 2019 coincided with reduced preemergence herbicide performance and wider differences among herbicide programs, whereas an earlier, higher amount of rain in 2020 provided greater weed control that was consistent with improved preemergence herbicide soil incorporation. Weed control in soybean was often greater than in cotton with a preemergence + early postemergence regimen in the drier year, consistent with faster canopy closure. Weed species responded similarly across programs, although preemergence-only control of morningglories was generally 20% to 30% lower than for Palmer amaranth and annual grasses. Relative yield reflected differences in weed control; plots without herbicides exhibited 70% to 90% losses, whereas late postemergence treatments achieved maximum yields. Results support pairing preemergence residuals with sequential herbicides applied postemergence and highlight the value of herbicides applied late postemergence to mitigate escapes of late-emerging weeds and avoid yield losses.

Auxinic herbicides are crucially necessary for maintaining effective weed management in modern agronomic systems. Palmer amaranth has evolved resistance to multiple herbicides, including auxinic herbicides. Since auxin resistance has been determined in Palmer amaranth, new strategies should be implemented to improve the weed’s management. Field studies were conducted in Tennessee during the summers of 2024 and 2025 to evaluate the efficacy of various herbicide application methods for managing auxin-resistant Palmer amaranth. The research compared tank-mixed applications of 2,4-D and glufosinate with split-boom applications (herbicides applied simultaneously through separate spray booms as independent solutions) to multiple Palmer amaranth populations. Results demonstrated that in populations that exhibited high resistance to auxinic herbicides, the split-boom application method was more effective than the conventional tank-mix method. However, control levels were still below those typically considered acceptable for effective Palmer amaranth control. Sequential split-boom applications were required to achieve acceptable levels of control in these populations. A second study evaluated whether carrier volume influenced the performance of these applications by comparing mixtures of 140 L ha−1 and 280 L ha−1. The results indicated that carrier volume did not significantly affect Palmer amaranth control at these volumes.

Nebraska has significant acreage under continuous corn production in which managing volunteer corn remains a persistent challenge for growers. A new premix of glufosinate/quizalofop (Zalo; AMVAC, Newport Beach, CA) was recently registered for weed control in glufosinate-resistant canola, cotton, and soybean. The objectives of this study were to 1) compare glufosinate/quizalofop with quizalofop (Assure II; AMVAC) applied at the V3 or V6 growth stages to control glufosinate/glyphosate-resistant volunteer corn in corn that is resistant to aryloxyphenoxypropionates (Enlist corn); and 2) evaluate interactions with 2,4-D and their effects on volunteer corn density, biomass, and corn yield. Field experiments were conducted in 2023 and 2024 near Clay Center, Nebraska (3 site-years) and in 2024 near Rosemount, Minnesota (1 site-year). Glufosinate/quizalofop applied at 706 or 948 g ai ha–1 provided 98% to 99% control of volunteer corn and reductions in density and biomass when assessed 28 d after application (DAA), regardless of volunteer corn density and planted corn growth stage at herbicide application, and these outcomes were comparable to those when quizalofop was applied at 65 or 86 g ai ha–1. When the lower rate of glufosinate/quizalofop (706 g ai ha–1) was mixed with 2,4-D (1,064 g ae ha–1), volunteer corn control ranged from 84% to 92% at 14 DAA in 2 site-years. Volunteer corn control improved to ≥96% by 28 DAA or when the higher rate of glufosinate/quizalofop (948 g ai ha–1) was mixed with 2,4-D and assessed at 14 DAA. Enlist corn yield increased in the plots that were sprayed with herbicides compared with nontreated control plots, with no difference among herbicide programs, and yield was comparable to that of the weed-free–treated plots. The results of this study indicate that glufosinate/quizalofop could provide an effective postemergence herbicide option for managing glufosinate/glyphosate-resistant volunteer corn, pending its registration for use on Enlist corn.

Palmer amaranth is a summer annual weed native to the southwestern United States and is particularly troublesome across the Cotton Belt. The use of soil-residual herbicides is crucial for cotton producers in the Texas High Plains attempting to achieve early season control of Palmer amaranth and other problematic weeds. A bare-ground field study was conducted in 2022 and 2023 in Halfway, Texas, to evaluate weed control following isoxaflutole + pendimethalin applied preplant incorporated (PPI) or pendimethalin PPI followed by (fb) isoxaflutole applied preemergence alone or combined with seven other cotton residual herbicides, and to determine whether using isoxaflutole PPI would be a useful option for rainfed production systems. In 2022, Palmer amaranth was completely controlled at 28 d after application (DAA) following isoxaflutole + pendimethalin applied PPI fb acetochlor or S-metolachlor applied preemergence, and pendimethalin applied PPI fb isoxaflutole in a tank-mix with diuron, fomesafen, acetochlor, or S-metolachlor applied preemergence. At 42 DAA, PPI treatments that contained isoxaflutole + pendimethalin fb preemergence applications of acetochlor or S-metolachlor, and a PPI treatment with pendimethalin fb isoxaflutole + acetochlor or S-metolachlor applied preemergence increased Palmer amaranth control by ≥12% compared with isoxaflutole + pendimethalin applied PPI fb prometryn applied preemergence and pendimethalin applied PPI fb isoxaflutole + prometryn applied preemergence. In 2023, when assessed at 42 DAA, Palmer amaranth was controlled by >90% with isoxaflutole + pendimethalin applied PPI fb fomesafen or S-metolachlor applied preemergence, and pendimethalin applied PPI fb isoxaflutole applied alone or in a tank-mixture with diuron, fluridone, fomesafen, acetochlor, or S-metolachlor applied preemergence. End-of-season aboveground Palmer amaranth fresh biomass did not vary among treatments in either year. These results suggest that soil-residual control of Palmer amaranth greater than 90% can be achieved for 7 to 9 wk using isoxaflutole-based treatments applied either PPI or preemergence. Furthermore, applying isoxaflutole PPI can be a useful option for achieving early season weed control in cotton production systems.

Trifludimoxazin + saflufenacil is a premixed herbicide that can be applied both preemergence and postemergence for burndown purposes ahead of planting corn, soybean, grain sorghum, and wheat. With early season corn growth often occurring simultaneously with preplant burndown of fields in later-planted soybean and grain sorghum, the odds increase that negative effects may be associated with off-target movement of the herbicide to the corn crop. Field studies were conducted in 2024 at seven locations to evaluate the effect of reduced rates of trifludimoxazin + saflufenacil (12.5% to 0.4% of the lowest application rate of 38.3 g ai ha−1 proposed by the manufacturer) applied to 2-leaf or 4-leaf corn. When assessed at 7 d after treatment (DAT), corn injury from early and later applications ranged from 21% to 3% and 19% to 5%, respectively, while at 14 DAT injury ranged from 12% to 5% and from 8% to 1%. At 28 DAT, the highest rate (1/8×) applied to 2-leaf corn resulted in 6% visible injury, whereas no other treatment resulted in more than 3% injury. Early season plant height was negatively affected, more so at the three highest rates applied and when the herbicide was applier earlier, but this reduction did not affect yield. Nevertheless, trifludimoxazin + saflufenacil should not be applied to a field adjacent to corn in the early vegetative stages of growth. Corn affected by off-target movement should, however, be expected to fully recover following 2-leaf exposure, with no effect on yield and minimal yield effects (<3% reduction) at later timing given adequate growing conditions and agronomic/pest management practices.

Wild licorice is increasing in abundance across sandy grasslands of the Canadian Prairies, yet little is known about how to manage this plant. We conducted two field studies documenting the long-term impact of various herbicides applied once in either spring or summer, and annual mowing in either spring or summer, on the abundance of wild licorice for up to five growing seasons (2016–2020). Herbicides led to variable reductions in licorice density and biomass between sites and over time, with the greatest reductions coinciding with summer rather than spring herbicides during the first 2 yr after treatment. Greater and more consistent decreases were evident from the application of aminopyralid and aminocyclopyrachlor, although all herbicides, including dicamba and 2,4-D, exhibited some suppression of licorice out to 4 yr after treatment. Reductions in wild licorice also varied with growing conditions, as drought reduced licorice biomass across all treatments, including the nontreated control. Unlike herbicides, annual mowing, particularly in summer (late July; the 9- to 10-leaf stage), increased wild licorice total annual biomass produced for up to two growing seasons, coincident with above-normal rainfall. With the onset of drought in Year 3, mowing effects dissipated and did not reappear through Year 5. Finally, while hand-pulling was initially effective in reducing wild licorice, its effects were short-lived, and the selective removal of neighboring herbs led to an increase in licorice during drought. Overall, these results highlight the challenge of managing wild licorice populations in grasslands and provide insight into the strategies that may aid the management of this species.

North Carolina farmers rely extensively on applying atrazine to their corn crops to achieve effective control of Palmer amaranth. In 2016, a farmer in Washington County, North Carolina, reported a failure of atrazine to control Palmer amaranth in a corn field. Greenhouse studies were conducted to confirm whether the Washington County Palmer amaranth population was resistant to atrazine and to assess the effectiveness of other effective postemergence herbicides. Two atrazine-susceptible Palmer amaranth populations collected from Edgecombe and Johnston counties were used for comparison. Greenhouse response assays confirmed the Washington County population is resistant to atrazine, with a lethal dose of 1,253 g ai ha−1 causing 50% mortality (LD50). This population was 7-fold and 9-fold less susceptible to atrazine than the populations in Edgecombe County (LD50 208 g ai ha−1) and Johnston County (LD50 155 g ai ha−1), respectively. Additionally, the LD80 (the lethal dose of atrazine that would cause 80% mortality) of the Washington County population (12,107 ga ai ha−1) was more than five times greater than the maximum labeled rate for atrazine. A subsequent screening of Palmer amaranth with field-use rates suggested that 2,4-D, dicamba, fomesafen, glufosinate, and mesotrione provide at least 79% or greater control of the Washington County population. The Washington County population was not effectively controlled by thifensulfuron or glyphosate, both of which have faced widespread resistance throughout North Carolina. The results of these experiments provide evidence that the Washington County population of Palmer amaranth is resistant to atrazine, glyphosate, and thifensulfuron, and effective herbicides to manage this population were confirmed.

Iptriazopyrid is a novel herbicide that inhibits 4-hydroxyphenylpyruvate dioxygenase. When it receives authorization for use in rice production, iptriazopyrid will be the first azole carboxamide herbicide to receive registration for use in the United States. Because herbicides are commonly mixed to broaden the weed control spectrum and efficacy, herbicide interactions with iptriazopyrid must be evaluated. Field experiments were conducted near Colt, Arkansas, in 2024 and 2025, to evaluate interactions between iptriazopyrid and either synthetic auxins or residual herbicides labeled for use in rice fields. The experiments were designed as a two-factor, randomized complete block design, with the presence of iptriazopyrid at 50 g ai ha−1 as the first factor and the presence of labeled synthetic auxins or residual herbicides as the second factor. Applications targeted barnyardgrass at the 3- to 4-leaf stage, and Colby’s method was utilized to determine herbicide interactions. Only 2,4-D demonstrated antagonism to iptriazopyrid throughout the experiments. When applied alone, iptriazopyrid provided 75%, 83%, and 79% barnyardgrass control at 1, 2, and 4 wk after treatment (WAT), respectively, compared with 12%, 18%, and 8% control when it was mixed with 2,4-D. The iptriazopyrid + triclopyr combination was antagonistic for barnyardgrass control at 1 and 2 WAT, with 61% and 73% control, respectively; however, the relationship was no longer significant at 4 WAT. Barnyardgrass density supported an antagonistic interaction between 2,4-D and iptriazopyrid because combinations of the two led to higher densities than iptriazopyrid applied alone. No residual herbicide antagonized iptriazopyrid for barnyardgrass control; nor did barnyardgrass densities differ when iptriazopyrid was applied alone. Overall, these findings show that iptriazopyrid offers reasonable flexibility when mixed with some, but not all, synthetic auxins labeled for rice, and that there is no reduction in barnyardgrass efficacy when mixed with residual herbicides.

Glyphosate has been a cornerstone of weed management in Illinois corn and soybean production by supporting conservation tillage, lowering production costs, and stabilizing yields. Growing regulatory scrutiny, litigation, herbicide resistance, and public concern, however, have raised the possibility of restrictions or a complete ban on glyphosate use. This paper evaluates the farm-level revenue consequences of a hypothetical glyphosate prohibition in Illinois agriculture. Using a staged analytical framework, we first quantify baseline glyphosate use and expenditures, then draw on the agronomic and economic literature to estimate yield elasticities for corn and soybean under a complete ban assuming no substitution (where a yield elasticity measures the percentage change in crop yield associated with a one-percent change in glyphosate use, capturing the sensitivity of production to its removal). We subsequently examine producer substitution toward alternative weed management programs and quantify the resulting changes in production costs and farm revenues under maintained yields. Finally, we extend the analysis to scenarios in which increased demand raises substitute input prices and yields decline modestly due to imperfect weed control performance. The results indicate that for corn and soybean producers combined, the statewide loss will be in the order of US$300 to $609 million per year, or about a 1.8% to 3.6% revenue loss. Our manuscript is the first one to offer a transparent, evidence-based assessment of how glyphosate removal would affect farm revenues through yield and cost channels.

Family farms are facing unprecedented challenges with low commodity prices and high input costs, combined with regulatory obstacles that threaten the availability and practical use of pesticides. Ensuring that U.S. agriculture has access to economically effective and safe pest management tools is paramount for the nation and the world as farmers produce safe and affordable food, feed, fiber, and fuel. Field experiments in squash crops were carried out to assess the weed control effectiveness and economic value of a standard herbicide program compared to six nonchemical alternatives. The alternatives included 1) cultivating squash fields multiple times with a sweep plow; 2) cultivating fields multiple times with a tine weeder; 3 and 4) hand weeding to supplement plow or tine weeding efforts to achieve 75% weed control; and 5 and 6) hand weeding to supplement plow or tine weeding to achieve 95% weed control. When herbicides were applied, 98% to 99% control of Palmer amaranth, large crabgrass, and wild radish was achieved at a cost of US$104 ha−1 for the season. Cultivation (with a tine weeder or plow) provided only 36% to 64% control of each weed at a cost of $144 to $207 ha−1, and yielding 83% to 85% less squash than when herbicides were applied. Supplementing cultivation with 9 to 13 h of hand weeding per hectare achieved approximately 75% control, resulting in weed control costs ranging from $916 to $1,073 ha−1, with 40% to 47% less squash fruit harvested than when herbicides were applied. To achieve 95% weed control, 92 to 98 h ha−1 of hand weeding was required, with yields being comparable to those when herbicides were applied but weed control costs ranged from $8,344 to $8,527 ha−1, an increase of 80 to 82 times above the herbicide option. This experiment demonstrates how plant protection efforts can increase crop yield and quality while reducing costly inputs, thus improving the likelihood of safe, affordable, and sustainable food production.

Oil palm is a commercially important crop that is cultivated throughout Africa, Asia, and Latin America. Due to favorable climatic conditions, oil palm cultivation is concentrated in Southeast Asia, with Indonesia, Malaysia, and Thailand accounting for approximately 87% of the global palm oil supply. Effective weed management is essential for maintaining oil palm productivity; however, excessive reliance on herbicides has raised concerns over herbicide resistance and environmental sustainability. This review evaluates current weed management strategies in oil palm plantations, including chemical, mechanical, cultural, and biological, with an emphasis on integrated weed management (IWM) strategies suitable for production systems in Southeast Asia. Particular attention is given to the differing weed management constraints faced by industrial plantations and smallholder producers, including variations in labor availability, operational scale, and access to weed management technologies. Current evidence suggests that combining complementary control tactics, such as integrating mechanical and cultural practices with chemical and biological control methods, offers greater long-term sustainability than reliance on herbicides alone. Individual practices, however, face significant limitations, including economic constraints, labor shortages, and inconsistent effectiveness, highlighting the importance of integrated strategies. We conclude that adaptive, multi-tactic IWM programs tailored to local production scales will be critical for sustainable weed management in future oil palm production.

Surveys of farmers and consultants provide valuable insights into emerging problems and shifts in crop production practices. University researchers and Extension personnel can use this information to direct research and Extension outputs to best meet on-farm needs. A survey of soybean farmers and consultants in the Midsouth region of the United States (Arkansas, Louisiana, Mississippi, southeastern Missouri, and Tennessee) was conducted from October 2024 through March 2025 to understand common weed management practices, problematic weed species, and evolving herbicide resistance. The survey respondents represented those who farm 19% of the total soybean-planted area in the Midsouth, accounting for more than 900,000 hectares. Soybean cultivars that are resistant to glyphosate, glufosinate, and dicamba had the highest adoption rate, accounting for 62% of hectares planted in 2024, with a projected increase to 66% in 2025. Among the survey respondents, S-metolachlor was the most widely used preemergence and postemergence residual herbicide, whereas dicamba was the most common postemergence herbicide used. The most problematic weeds infesting Midsouth soybean fields were Palmer amaranth, prickly sida, barnyardgrass, morningglories, and Italian ryegrass. A significant portion of farmers and consultants suspect that Palmer amaranth has become resistant to synthetic auxins (47%) or glufosinate (52%). Respondents cited the ability to control problematic weed species as the most needed research area and frequently requested research on managing herbicide resistance and alternative cultural practices for weed control. Herbicide resistance is a key concern for farmers, and postemergence herbicide options are increasingly limited, yet there is strong interest in integrated weed management and in adopting new technologies in soybean.

Rice is often planted in the mid-southern United States around the same time that paraquat is applied either preplant or preemergence herbicide to other row crops in adjacent fields. Additionally, off-target movement of paraquat may occur onto rice late in the season due to paraquat’s use as an aid in soybean harvest. Although previous research has documented rice response to early season and late-season exposure to sublethal concentrations of paraquat, research quantifying rice injury after multiple exposures is not available. Therefore, research was conducted from 2019 to 2021 in Mississippi with the aim of evaluating rice growth and yield after exposure to sublethal concentrations of paraquat multiple times during the rice life cycle. Paraquat (84 g ai ha−1) was applied to rice at the spiking to 1-leaf (VEPOST) and 3- to 4-leaf (MPOST) growth stages to simulate early season exposure, while late-season exposure of paraquat was simulated with applications to rice at a rate of 28 g ai ha−1 when 50% of plants in a plot had visible panicles (HEAD) to the day of draining (DRAIN), and a sequential treatment with rice exposure at HEAD followed by DRAIN. Rice injury was greatest pooled across early season exposure, when paraquat exposure occurred at HEAD followed by DRAIN. Rough rice grain yield was reduced by 15% and 18% from HEAD and HEAD followed by DRAIN exposures, respectively, compared with the no-late-season exposure. Whole milled rice yields were not affected by multiple exposures to paraquat. Multiple exposures to paraquat had the greatest effect on rice performance when the exposure occurred both early and late in the season.