In Oklahoma, downy brome and cheat are difficult-to-control winter annual grasses. In the past, cheat infested most of the winter wheat hectares harvested in Oklahoma. Biotypes that are cross-resistant to acetolactate synthase–inhibiting herbicides have left growers with minimal management options for conventional and herbicide-tolerant systems. Field trials near Lahoma, Oklahoma, in 2019–2020 and 2020–2021 evaluated integrated management of cheat and downy brome using three strategies: planting date (optimal, delayed, and late), cultivar selection (high and low competitiveness), and herbicide choice (no herbicide, sulfosulfuron at 35.2 g ai ha−1 and pyroxsulam at 18.4 g ai ha−1). Visual control, weed species present, wheat biomass at heading, and grain yield data were collected. In 2019–2020, 8 to 9 wk after treatment, visual control increased by 15% with the delayed planting compared with the optimal planting date and 14% with the late planting date. In 2020–2021, similar control (∼99%) was recorded for delayed and late plantings with 23% greater control than the optimal timing. Due to a lack of weed coverage, weed biomass in 2019–2020 had no response to planting date, cultivar, or herbicide treatment. Downy brome biomass during 2020–2021 was approximately 90% lower with delayed to late planting dates than the optimal planting date. In the same year, downy brome and cheat biomass were low (≤0.4 and 0.2 g m−2) and 98% less after an herbicide application than a nontreated area. Wheat grain yield at the optimal planting date was greater than yields from delayed and late plantings in 2019–2020. A delay in planting from the optimal date to delayed or late timings decreased wheat yield by 14% and 21%, respectively. In 2020–2021, wheat yield from the late planting was reduced by 57% compared with the optimal planting yield. Delaying the planting date and the use of a common herbicide can suppress cheat and downy brome, but a decline in wheat yield may occur.

Herbicide management information is lacking for recently developed turf-type bahiagrass germplasm. The objective of this study was to evaluate the herbicide tolerance of nine experimental bahiagrass genotypes compared to the industry standard ‘Argentine’. The experimental entries included Argentine and ‘Wilmington’ mutants, and wild-type breeding lines. Plants were grown under greenhouse conditions, and 12 herbicides were applied at 1× and 2× labeled rates. Bentazon, bromoxynil, carfentrazone + 2,4-D + MCPP + dicamba, and carfentrazone were classified as safe. Fluroxypyr, halosulfuron, and triclopyr + clopyralid reduced growth >50% when applied at twice the label rate. Fenoxaprop, sulfentrazone + imazethapyr, and thiencarbazone + iodosulfuron + dicamba reduced growth and caused turfgrass injury above an acceptable threshold (≥20%). In general, the Argentine mutants showed greater herbicide injury compared to the Wilmington mutants. However, metsulfuron exceeded the acceptable injury threshold and stopped growth in all the genotypes, Argentine and genotype WT6 were the least injured by this herbicide. The experimental genotype WT6 consistently showed the greatest herbicide tolerance. Except for one genotype (WT4), the experimental genotypes responded similarly or better than Argentine to the tested herbicides, except for metsulfuron.

Pintoi peanut is a warm-season perennial legume that shows promise as a forage crop for the southeastern United States, however, little is known about the proper methods of weed management during establishment for this species. The objective of this study was to determine the ability of pintoi peanut to tolerate applications of PRE and POST herbicides during the year of and year after planting. The effects of herbicide treatments on percentage of visual estimates of injury and stand counts of pintoi peanut were investigated at Ona and Marianna, FL, in 2015 and 2016. All PRE herbicides did not result in significant injury or stand reduction. Pintoi peanut’s tolerance to POST herbicides was higher when plants were emerged for at least 2 wk prior to herbicide application. Stands of pintoi peanut that were planted the previous year appear to tolerate all herbicides examined in this work, except sulfosulfuron. Results of this study indicate that at the year of planting pintoi peanut is tolerant to PRE applications of pendimethalin, imazethapyr, and imazapic. Pintoi peanut appears to tolerate applications of 2,4-D, carfentrazone, imazapic and imazethapyr the year after planting at the rates utilized in this study. Future research should evaluate the effects of multiple herbicide applications and tank-mixes to obtain satisfactory weed control and selectivity in pintoi peanut swards.

Grape hyacinth is a perennial bulbous species in the Liliaceae. It is commonly grown as an ornamental plant, but it can spread into agricultural fields and become weedy, potentially interfering with harvest and fall-planted crops. There has been limited research on controlling grape hyacinth in cropping systems. Fall and spring applied field-research studies were conducted to determine grape hyacinth control with herbicides labeled for use in wheat or winter fallow before planting soybean. Among fall-applied herbicides, paraquat resulted in the greatest initial grape hyacinth control (90% to 100%). Grape hyacinth control, 16 months after application (MAA), was variable, but the top-performing treatments were glyphosate and metsulfuron plus paraquat, resulting in 65% and 50% control, respectively. After spring applications, grape hyacinth control in November (7 MAA) was variable, but top-performing treatments were glyphosate and metsulfuron, which resulted in at least 26% control. Spring-applied paraquat, carfentrazone, metsulfuron, and sulfosulfuron resulted in 73%, 68%, 69%, and 60% reductions in grape hyacinth bulb counts, compared with the nontreated control 7 MAA, and were the top-performing treatments. Despite product-label prohibitions on rotation to soybeans, no soybean yield reductions were observed from any treatment in either study. Single applications of certain herbicides in the fall or spring can result in good control (>80%) of grape hyacinth initially, but long-term control is poor, and additional research is required.

A Bromus tectorum L. (downy brome) biotype with cross-resistance to sulfosulfuron has been identified. The resistant biotype was selected with primisulfuron in Poa pratensis L. (Kentucky bluegrass) plots near Madras, OR. The plots received two treatments of 20 g ai ha−1 primisulfuron in the fall of 1993, 1994, and 1995. In 1995, control of B. tectorum decreased and greenhouse studies confirmed that the biotype was resistant to primisulfuron. Cross-resistance to sulfosulfuron also was confirmed in greenhouse studies. Metabolism of sulfosulfuron rather than an insensitive site of action is the likely cause of the cross-resistance.

Cut-leaved teasel is an invasive weed along highway corridors and is classified noxious in four states, including Missouri. Few herbicides have been examined for cut-leaved teasel control. Herbicides were evaluated for efficacy on established plants and residual activity for suppressing seedling emergence. Various growth regulator herbicides, amino acid inhibitors, and paraquat were applied on established teasel at two locations in central Missouri in fall 2003 and spring 2004, and two additional locations in fall 2004 and spring 2005. At 2 wk after treatment (WAT), paraquat resulted in the highest injury of teasel (85%), but injury declined over time. At 4 WAT, teasel control was most consistent with dicamba + diflufenzopyr applied in spring, ranging from 75 to 94% control. At 8 wk, glyphosate, dicamba + diflufenzopyr, metsulfuron-methyl, imazapyr, and combinations of growth regulator herbicides with 2,4-D were most effective, with teasel control from 86 to 100%. Control with 2,4-D alone was inconsistent; sulfosulfuron, sulfometuron-methyl, and paraquat were ineffective. Residual herbicides did not reduce teasel seedling emergence the following year. A number of herbicides were effective in managing emerged plants but reinfestations of treated sites is likely, even with the residual herbicides used in this research.

Field dodder is a parasitic plant that attaches to the stems and leaves of broadleaf plants, including weeds, field crops, vegetables, and ornamentals, throughout most agricultural regions of the world. Effective field dodder control is extremely difficult to achieve, due to the nature of attachment and close association between host and parasite, which requires a highly effective and selective herbicide to destroy the parasite without crop damage. Previous studies have demonstrated the tolerance of certain tomato varieties to dodder parasitism. The aim of the present study was to evaluate the ability of sulfonylurea herbicides to control field dodder under greenhouse and field conditions. Two greenhouse studies and three field studies were conducted to evaluate the efficiency and crop selectivity of the sulfonylurea herbicides sulfosulfuron, rimsulfuron, halosulfuron, and flazasulfuron in controlling field dodder parasitizing tomato plants. Sulfosulfuron at 50 or 100 g ai ha−1 was effective and safe for tomato in field dodder control, while the other herbicides exhibited little or no dodder control.

Sulfonylurea herbicides used in turfgrass—including chlorsulfuron, flazasulfuron, foramsulfuron, halosulfuron, metsulfuron, rimsulfuron, sulfometuron, sulfosulfuron, and trifloxysulfuron—are all weak acids, with disassociation constants ranging from 3.3 to 5.2. Sulfonylureas are used at low rates ranging from 4 to 280 g ha−1. Although these use rates put their soil concentration in parts per billion, they still have residual activity with variable persistence. They have limited susceptibility to soil leaching with weak adsorption to soil clay minerals. Sulfonylurea herbicides used in turfgrass have variable soil organic matter adsorption, which is soil dependent. The persistence and activity of these sulfonylureas are affected by soil pH. At soil pH of 7.0 and greater, some of these sulfonylurea herbicides tend to persist for longer periods with half-lives extending into years rather than days. In normal use patterns with soil pH of 7.0 and less, dissipation occurs via chemical hydrolysis and microbial degradation with half-lives ranging from days to months. Overall, sulfonylurea herbicide adsorption is negatively correlated to increasing pH (increased persistence) and positively correlated to increased organic matter (decreased activity).

Acetolactate synthase (ALS) inhibitors are widely used for POST control of sedges in turfgrass. A suspected resistant (R) biotype of annual sedge was collected from a bermudagrass turf in Georgia with a history of exclusive use of halosulfuron. Research was conducted to evaluate the resistance level of this biotype to halosulfuron, efficacy of ALS-inhibiting herbicides and other mechanisms of action for control, and the molecular and physiological basis for resistance. In greenhouse experiments, the halosulfuron rate required to reduce shoot biomass 50% in comparison with the nontreated at 8 wk after treatment (WAT) were 8 and > 1,120 g ai ha−1 for the S (susceptible) and R biotypes, respectively. Imazapic, sulfosulfuron, and trifloxysulfuron reduced biomass of the S biotype greater than 60% at 8 WAT, but biomass was reduced less than 20% for the R biotype. Glufosinate, glyphosate, MSMA, and sulfentrazone reduced shoot biomass of the R biotype by 93, 86, 97, and 45%, respectively. In laboratory experiments, the halosulfuron concentration required to inhibit ALS activity by 50% in excised leaf tissues was 5.8 and > 1,000 μM for the S and R biotypes, respectively. Gene sequencing of the R biotype revealed a Pro-197-Ser substitution that confers resistance to ALS inhibitors. This is the first report of ALS-inhibitor resistance in annual sedge and herbicide resistance in a sedge species from a turfgrass system.

Field experiments were conducted in north-central Oklahoma to evaluate the effects of MON 37500 at 35, 70, and 140 g ai/ha applied to wheat on rotational crops seeded no-till 16 to 29 mo after treatment (MAT). Wheat yields were not reduced by MON 37500 at site 1 but at site 2 were decreased 6, 11, and 24% by 35, 70, and 140 g/ha, respectively. Wheat yield reductions at site 2 were attributed to late seeding, small wheat growth stage, and cool, wet weather during the month after application. Corn and soybean seeded approximately 16 MAT were not visibly injured by residual MON 37500 at any rate at either site. At site 1 grain sorghum seeded 17 MAT was visibly injured by residual MON 37500 applied at 70 and 140 g/ha (soil pH value 6.4), and grain yield was reduced 58% by residual MON 37500 applied at 140 g/ha. Grain sorghum seeded 17 MAT was not visibly injured at site 2 (soil pH value 5.0), and that seeded 29 MAT was not injured at either site. Sunflower seeded 17 MAT at site 1 was visibly injured by residual MON 37500 at 140 g/ha, and yield was reduced 17% but at site 2 was not affected by MON 37500. Sunflower seeded 29 MAT was not injured at either site.

Littleseed canarygrass is a major weed of winter-season crops, although it is most dominant in wheat-growing regions in the Indo-Gangetic Plains of India, Pakistan, Nepal, and Bangladesh. Resistance in this species to photosystem II–inhibiting herbicide isoproturon was first recorded in 1992, and has since spread to several Indian states covering more than a million ha. Genetic studies and resistance characterization from multiple locations indicate independent evolution of resistance due to continuous use of isoproturon and monoculture rice–wheat-cropping system. Isoproturon-resistant biotypes were found cross-resistant to diclofop, but not to chlortoluron, which has the same mode of action as isoproturon. The isoproturon-resistance mechanism is metabolic degradation, mediated by P-450 monooxygenase enzymes. This type of resistance could become serious and lead to the evolution of multiple resistances to herbicides of different modes of action. Adoption of fenoxaprop-P, clodinafop, and sulfosulfuron in isoproturon-resistant areas since 1997 initially led to high yields, but resulted in a weed flora shift which eventually reduced yields and increased the cost of weed management. Although isoproturon recommendation has been withdrawn from rice–wheat cropping zones, resistance in littleseed canarygrass is spreading in other areas where isoproturon has been used for several years because it is inexpensive and has broad-spectum weed control. Management factors, such zero or minimum tillage, early planting after rice harvest, and alternative herbicides provide effective control of resistant biotypes. However, lower efficacy of these herbicides has been observed in the field, although multiple resistances have yet to be confirmed. Herbicide rotations, mixtures, and sequences are beneficial, but only in the short term. Improved cultivation practices are also helpful; however, no current single system is sustainable. An integration of tillage method, planting time, varietal selection, crop rotation, timing and method of herbicide application, optimum dose, and sanitation practices is crucial in managing herbicide-resistant littleseed canarygrass.

Field experiments were conducted at Adelphia, NJ, in 2001 and 2002 to evaluate the response of Kentucky bluegrass, perennial ryegrass, tall fescue, and Chewings fine fescue to sulfosulfuron. Single applications of sulfosulfuron at 6 to 67 g ai/ha were applied to mature swards of each species. Visual chlorosis ratings were taken and clippings were collected 4 wk after treatment (WAT), and turf injury was rated 8 WAT. Chlorosis on all species increased with increasing sulfosulfuron rate. In 2001, Kentucky bluegrass, perennial ryegrass, tall fescue, and fine fescue chlorosis reached 33, 43, 65, and 61% at 4 WAT, respectively, whereas in 2002, chlorosis only reached 13, 26, 46, and 26%, respectively. Clipping weights of all species decreased as application rate increased. Reductions in Kentucky bluegrass and perennial ryegrass clipping weights were less severe than those in tall and fine fescue. By 8 WAT, Kentucky bluegrass, perennial ryegrass, and fine fescue had nearly complete recovery from any initial visual injury symptoms. However, tall fescue injury was still evident 8 WAT in both years. Initial injury of Kentucky bluegrass, perennial ryegrass, and Chewings fine fescue was in the form of discoloration and stunting. Significant stand thinning was only evident in the tall fescue studies. These studies suggest that Kentucky bluegrass and perennial ryegrass may be more tolerant than tall fescue to applications of sulfosulfuron and fine fescue is intermediately tolerant to sulfosulfuron.

Greenhouse experiments were conducted to evaluate the effect of selective herbicide placement on sedge shoot number, shoot weight, and root weight. Sulfentrazone, sulfosulfuron, and trifloxysulfuron were applied to soil only, foliage only, or soil plus foliage. Sulfentrazone provided greater yellow nutsedge and false green kyllinga growth reduction compared to purple nutsedge. Sulfosulfuron provided greater purple nutsedge and false green kyllinga growth reduction compared to yellow nutsedge; these species responded similarly to trifloxysulfuron. Soil and soil plus foliar applications provided the highest level of growth suppression, indicating herbicide–soil contact is required for optimum sedge control with these three herbicides. Future research should evaluate techniques that optimize herbicide–soil contact to improve herbicide efficacy.

Experiments were conducted during 2007 and 2008 to evaluate various herbicide treatment regimes for POST purple nutsedge and false-green kyllinga control. Evaluated herbicides included halosulfuron, sulfentrazone, sulfosulfuron, and trifloxysulfuron. Evaluated treatments did not cause objectionable bermudagrass injury at any time. Results were variable across years, likely due to reduced rainfall in 2007 causing reduced purple nutsedge and false-green kyllinga growth. In 2007, averaged across herbicide rate and number of applications, sulfosulfuron provided greater purple nutsedge control than trifloxysulfuron. Sulfosulfuron and trifloxysulfuron provided similar levels of control in 2008, although both were less effective than in 2007. In 2007, sulfosulfuron and trifloxysulfuron provided excellent (> 90%) false-green kyllinga control, and trifloxysulfuron provided greater control (80%) compared to sulfosulfuron (61%) in 2008. Sulfentrazone provided < 30 and 60% purple nutsedge and false-green kyllinga control, respectively. A sequential application applied 6 wk after initial treatment provided the highest level of purple nutsedge and false-green kyllinga control with evaluated herbicides. Tank-mix partners to enhance purple nutsedge control with sulfentrazone provided inconsistent results. Sulfosulfuron and trifloxysulfuron offer acceptable POST perennial sedge control in tolerant warm-season turfgrasses.

Several sulfonylurea herbicides are labeled for use on established bermudagrass or seashore paspalum, but label recommendations for many of these chemicals vary for sprigged turf. The objective of this study was to determine the safety of various sulfonylurea herbicides on newly planted, ‘Tifway’ bermudagrass and ‘Aloha’ seashore paspalum sprigs in Arkansas and Louisiana. Treatments were arranged as a five by two by two factorial with five herbicides (foramsulfuron at 29 and 59 g ai ha−1, halosulfuron at 35 and 70 g ai ha−1, metsulfuron at 21 and 42 g ai ha−1, sulfosulfuron at 66 and 131 g ai ha−1, and trifloxysulfuron at 28 and 56 g ai ha−1), two herbicide rates (low and high), and two application timings at 2 or 4 wk after sprigging (WAS). There was no discernable herbicide injury to, or reduction in, Tifway bermudagrass coverage in Arkansas, regardless of herbicide, application timing, or application rate. Trifloxysulfuron and metsulfuron were more injurious than other herbicides in Louisiana when applied at 2 WAS to Tifway bermudagrass, but injury levels were acceptable (< 15%), and there was no long-term reduction in establishment. Metsulfuron or halosulfuron applied at 2 or 4 WAS and sulfosulfuron applied at 4 WAS allowed > 90% establishment of Aloha seashore paspalum at both locations. Both trifloxysulfuron and foramsulfuron were injurious to seashore paspalum and reduced its establishment. These results suggest that sulfonylurea herbicides can be safely applied shortly after sprigging to Tifway bermudagrass and that metsulfuron, halosulfuron, and sulfosulfuron could be useful herbicides for establishing Aloha seashore paspalum from sprigs.

Field studies were established in 1999 and 2000 to evaluate Italian ryegrass, wheat, and double-crop soybean response to fall and spring postemergence applications of flucarbazone, sulfosulfuron, clodinafop, diclofop, and tralkoxydim applied alone and in combination with thifensulfuron + tribenuron to winter wheat. Fall-applied herbicides caused 5% or less wheat injury. Spring-applied herbicides caused 3 to 45% wheat injury, and the greatest injury occurred with the combination of flucarbazone with thifensulfuron + tribenuron in the spring of 2001. Spring-applied sulfosulfuron, tralkoxydim, diclofop, and clodinafop caused 3 to 6% and 16 to 26% wheat injury in 2000 and 2001, respectively. Herbicide injury to wheat did not reduce wheat grain yield compared with the hand-weeded treatment. Italian ryegrass competition in the nontreated plots reduced wheat yield by as much as 33% compared with herbicide-treated plots. Italian ryegrass control was 89 to 99% from clodinafop and diclofop and 78 to 97% from flucarbazone, with no differences because of application timing in either year of the study. Italian ryegrass control from sulfosulfuron and tralkoxydim was greater from the spring of 2000 applications (94 to 99%) compared with the fall of 1999 applications (65 to 88%). However, in 2001, application timing (fall vs. spring) for sulfosulfuron and tralkoxydim did not affect Italian ryegrass control. Thifensulfuron + tribenuron combined with tralkoxydim reduced control of Italian ryegrass control compared with tralkoxydim alone in both years of the study. Italian ryegrass control was not reduced when thifensulfuron + tribenuron was combined with sulfosulfuron, flucarbazone, diclofop, or clodinafop. Italian ryegrass was controlled effectively by the acetyl-CoA carboxylase–inhibiting herbicides diclofop, clodinafop, and tralkoxydim. However, control of Italian ryegrass with the acetolactate synthase–inhibiting herbicides flucarbazone and sulfosulfuron was inconsistent. Double-crop soybean after wheat did not have foliar symptoms or yield loss from fall- or spring-applied herbicides.

Annual bluegrass is a troublesome weed of Kentucky bluegrass because of a lack of selective POST herbicides for control. Field experiments were conducted in New Jersey to investigate the potential of bispyribac-sodium, primisulfuron, and sulfosulfuron for selective annual bluegrass control in Kentucky bluegrass. Primisulfuron provided the best combination of Kentucky bluegrass safety and annual bluegrass control with greater efficacy in summer than fall. Bispyribac-sodium also provided substantial annual bluegrass control, especially in the summer, but caused unacceptable (> 20%) Kentucky bluegrass injury, whereas annual bluegrass control with sulfosulfuron was inconsistent. Growth chamber experiments confirmed that greater primisulfuron efficacy in summer than fall may be attributed to higher temperatures. Overall, primisulfuron has promising implications for future use in Kentucky bluegrass for annual bluegrass control whereas bispyribac-sodium will likely be more applicable in other cool-season turfgrasses.

Much research has evaluated herbicide safety on established bermudagrass turf, but information is lacking on seedling response to herbicides. Three field experiments were conducted in Blacksburg, VA, to assess turfgrass and smooth crabgrass response to selected sulfonylurea herbicides during seedling bermudagrass establishment. Herbicides injured bermudagrass 9 wk after treatment in the following order from most to least injurious: flazasulfuron = trifloxysulfuron > rimsulfuron > metsulfuron = sulfosulfuron > foramsulfuron. Herbicides applied 3 wk after seeding (WAS) were generally more injurious than when applied 1 WAS. Flazasulfuron and trifloxysulfuron-sodium controlled smooth crabgrass greater than 90% at 6 WAS, and metsulfuron and rimsulfuron suppressed smooth crabgrass 76 and 84%, respectively. Foramsulfuron, metsulfuron, and sulfosulfuron appear safe to apply 1 and 3 WAS, causing very little chlorosis and no reduction in turf cover. Rimsulfuron is injurious when applied at those timings; however, long-term cover is not reduced. Flazasulfuron and trifloxysulfuron-sodium are not safe to use 1 and 3 WAS unless weed pressure is extreme, and a delay in bermudagrass cover is acceptable.

The agrestal field violet, a pervasive weed in Europe, has been identified in reduced-tillage cereal fields in Alberta. The efficacy of herbicides in direct-seeded spring wheat was assessed on natural field violet infestations in Alberta in 2002 and 2003. Only fluroxypyr + 2,4-D, applied postemergence, provided control of field violet in 2002 when rainfall was limiting. Over both years, this herbicide combination reduced biomass by 59 to 69% and plant density by 83 to 91%, relative to nontreated plots. The herbicides metsulfuron, sulfosulfuron, and thifensulfuron + tribenuron only suppressed weed growth under drought conditions in 2002 but controlled the weed in 2003 when rainfall was greater, reducing plant density by 82 to 92% and rendering remaining plants sterile. Suppression was also observed with MCPA + mecoprop + dicamba in 2002 and 2003 and with metribuzin only in 2003. Effective control of field violet was conferred by a pre–crop emergence application of glyphosate at 445 g ae/ha in 2003, the only year that this treatment was evaluated. Activity of herbicides on three- to four-leaf seedlings was also evaluated in a greenhouse dose– response assay. All herbicides had greater efficacy in the greenhouse, and those that provided control in situ reduced field violet dry weight by 85% at less than the recommended rate used in field experiments. Management of field violet is possible with herbicides registered for use on spring wheat in Alberta. However, the weed does not appear to cause significant crop production losses; hence, herbicide selection should be based on knowledge of all weed species present within the field.

In the southeastern United States many farmers double-crop winter wheat with soybean or cotton. However, there is little information about residual injury of herbicides used in wheat to these rotational crops. Experiments were conducted from 2007 to 2008 and 2008 to 2009 in soft red winter wheat to evaluate response of rotational crops of soybean and cotton after application of various acetolactate synthase herbicides in wheat. Pyroxsulam, mesosulfuron, sulfosulfuron, propoxycarbazone, or chlorsulfuron plus metsulfuron at multiple rates were applied to wheat approximately 110 to 120 d before planting rotational crops. Soils were Tift loamy sand at Ty Ty, GA and Faceville sandy loam at Plains, GA. After wheat harvest, soybean (‘Pioneer 97M50’) and cotton (‘DP 0949 B2RF’) were strip-tillage planted and evaluated for injury, stand density, height over time, and yields. For both locations, wheat was tolerant to all herbicide treatments with little to no visible injury 7 to 90 d after application. Pyroxsulam injury was less than sulfosulfuron or mesosulfuron. At recommended use rates, wheat injury was transient with no effect on yield. Double-crop soybean for both locations had no differences in stand establishment for any herbicide treatments. There was significant carryover injury to soybean and cotton for sulfosulfuron applied to wheat for the Faceville sandy loam. There was no effect of herbicide treatment on cotton stand. There was little to no difference in residual activity on rotational crops between pyroxsulam and other wheat herbicides when labeled rates were applied. This is significant as pyroxsulam is used to control Italian ryegrass and wild radish in this region.