Early-season weed competition may cause substantial yield losses in onion. Oxyfluorfen and bromoxynil are POST herbicide options for weed control once onion has developed two leaves, which often takes 4 to 6 wk. Multiple applications of oxyfluorfen at 35 and 18 g ai ha−1 and bromoxynil at 35 and 18 g ae ha−1 with adjuvants were evaluated for onion safety and weed control under controlled greenhouse conditions. Oxyfluorfen at 35 g ha−1 plus organosilicone surfactant caused 42% onion injury at 12 d after three sequential applications. Onion treated with bromoxynil at 18 g ha−1 plus high surfactant oil concentrate had lower fresh weight (0.7 g) compared to methylated seed oil (MSO) (1.2 g) or petroleum oil concentrate (POC) (1.3 g) at the same bromoxynil rate. The addition of nonionic surfactant to bromoxynil, averaged across bromoxynil rates, provided 17 and 39% control of redroot pigweed and common lambsquarters, respectively. Redroot pigweed control with oxyfluorfen at 35 or 18 g ha−1 plus any tested adjuvant was excellent (≥ 93%). Results suggested the use of POC or MSO with either oxyfluorfen or bromoxynil for subsequent field trials because of similar common lambsquarters and redroot pigweed control and onion safety.

Amicarbazone is a photosystem II–inhibiting herbicide recently registered for annual bluegrass control in established turf systems that include creeping bentgrass. However, research to date reveals potential issues with creeping bentgrass tolerance to amicarbazone. Currently, the plant-growth regulator paclobutrazol is widely adopted by turf managers for chemical annual bluegrass suppression in creeping bentgrass putting greens. Field experiments were conducted throughout North Carolina in the spring of 2010 and 2011 to assess treatment regimens that included amicarbazone (49, 65, or 92 g ai ha−1) and paclobutrazol (70, 140, or 280 g ai ha−1) applied alone, as tank-mixtures, or used in tandem, at varying rates and sequential timings for annual bluegrass control in creeping bentgrass putting greens. In general, regimens including both compounds provided greater annual bluegrass control and acceptable turfgrass tolerance compared with stand-alone applications of amicarbazone at 8 and 12 wk after initial treatment (WAIT). When comparing regimens that included amicarbazone at 49 or 65 g ha−1, creeping bentgrass tolerance was greater for the higher application rate applied less frequently. These results indicate amicarbazone usage on creeping bentgrass greens may be beneficially affected with the incorporation of paclobutrazol to treatment regimens because annual bluegrass control with the combination was equal to or greater than stand-alone amicarbazone applications, and creeping bentgrass tolerance was superior 8 and 12 WAIT.

Giant miscanthus is under consideration as a biofuel crop in the United States; however, there is little information on weed management for the establishment and survival of this crop. Therefore, greenhouse and field studies using ornamental pots were conducted in summer 2011 at Tifton, GA, with the objective of screening potential PPI, PRE, and POST herbicides and herbicide combinations for giant miscanthus when establishing from vegetative rhizomes. For the POST treatments, giant miscanthus was established from rhizomes in 7.6-L containers in the field and treated with 27 POST herbicides to evaluate efficacy. Thifensulfuron, metsulfuron, tribenuron, chlorimuron, halosulfuron, rimsulfuron, cloransulam, pinoxaden, bentazon, and metribuzin did not significantly lower shoot height, reduce shoot dry weight, or increase injury compared with nontreated control (NTC) when evaluated at 4 wk after treatment. Nicosulfuron, trifloxysulfuron, sulfometuron, clodinafop, fluazifop, and pyrithiobac caused the greatest injury, reduced plant height, and reduced dry weights compared with the NTC. Sethoxydim, diclofop, flumioxazin, imazamox, imazapic, and imazethapyr decreased plant heights or resulted in increased injury. PPI and PRE treatments included 21 herbicides and herbicide combinations applied at two rates. Results indicated that most treatments containing atrazine, metribuzin, pendimethalin, acetochlor, metolachlor, and mesotrione did not injure or stunt growth; however, EPTC at 4.5 kg ai ha−1 significantly reduced height and dry weight and oxadiazon resulted in greater injury compared with NTC at both rates. These results indicate that PPI, PRE, and POST herbicides can be utilized for establishment of giant miscanthus from vegetative rhizomes. Considering the invasive potential of giant miscanthus, several POST herbicides evaluated in this study such as fluazifop, pyrithiobac, and sulfometuron may be viable options to control this species if it becomes invasive.

Methyl bromide (MBr) has been an industry standard for soil fumigation in a multitude of crops for decades. However, it has been banned by the United Nations Environment Programme, and alternatives to MBr must be implemented to sustain productivity in many vegetable crops that depend on soil fumigation. One alternative that has been implemented in some areas is methyl iodide (MeI). Efficacy of MeI has been demonstrated on many pest species and has been generally similar to MBr. Methyl iodide is a costly material, which has likely limited its adoption. Virtually impermeable film (VIF) and totally impermeable film (TIF) provide greater fumigant retention than low-density and high-density polyethylene film, which can allow for reduced fumigant application rates while maintaining fumigant efficacy. The objectives of this research were to evaluate TIF with reduced rates of shank-applied MeI : chloropicrin (Pic) (50 : 50 w/w) for the control of yellow nutsedge in tomato. Treatments included a standard rate of MeI : Pic (93.3 L ha−1 [178 kg ha−1 broadcast]) under VIF and TIF, three reduced rates (37.3, 56, 74.6 L ha−1 [71.2, 106.8, 142.5 kg ha−1 broadcast, respectively]) under TIF, and a nontreated control under TIF. Results indicate fumigant use rates may be reduced from a standard 93.3 L ha−1 under VIF to 37.3 L ha−1 (60% reduction) under TIF while providing yellow nutsedge control and maintaining tomato yields.

Clovers are commonly included as utility plants within mixed grass swards, such as pastures and roadside right-of-ways. As such, they provide supplemental nitrogen, quality forage, and insect habitat. Yet weed control within mixed swards is often hampered by the lack of selective herbicides that are tolerated by clovers. Differential tolerance of legumes to common row-crop and pasture herbicides has previously been reported, yet little information is available that is specific to clover species. Herbicide injury of clover is often inconsistent, hypothetically due to differential species tolerance. Field and greenhouse experiments were conducted with the objective of testing differential tolerance amongst four clover species. Our experiments suggest varying tolerances amongst clover species and common broadleaf herbicides. Only imazaquin control differed due to species; however, treatment by clover interactions were further demonstrated due to variable reductions in clover height. Imazaquin, 2,4-D, 2,4-DB, and triclopyr height reductions differed due to clover species. Differential clover response to herbicide treatment should be an important consideration when managing mixed grass–clover swards and should be accounted for in future research. On a more practical level, our experiments demonstrate a range of herbicides that effectively control clover species, including atrazine, dicamba, clopyralid, 2,4-D, triclopyr, metsulfuron, and trifloxysulfuron. However, results suggest that 2,4-DB, imazethapyr, and bentazon are candidate herbicides for weed control in scenarios in which clover is a desirable crop.

The pH and hardness of water used as agrochemical carrier can influence herbicide efficacy. The objective of this research was to determine the role of carrier water pH and hardness on saflufenacil efficacy and solubility. Saflufenacil was mixed in eight different carrier waters with one of five pH levels (4.0, 5.2, 6.5, 7.7, 9.0) or one of three hardness levels (0, 310, 620 mg L−1) and applied POST to common lambsquarters and giant ragweed in a field experiment and to field corn in a greenhouse experiment. Solubility testing was also completed on saflufenacil mixed in the five pH levels used in the field and greenhouse experiments. Water hardness did not influence the efficacy of saflufenacil on common lambsquarters, giant ragweed, or field corn. Control of giant ragweed or common lambsquarters in field experiments was reduced by up to 56% when saflufenacil was applied in water with a pH of 4.0 compared with water with a pH of 7.7. When nonsoluble saflufenacil was removed from the spray solution, saflufenacil efficacy on field corn in the greenhouse was reduced by 61% or more when applied in water with a pH of 4.0 than when applied with water with a pH of 5.2 or higher. When nonsoluble saflufenacil was applied with the soluble saflufenacil in the spray solution, at least a 7% reduction in control of field corn was observed when applied in water with pH of 4.0 as compared with saflufenacil applied in water with pH of 5.2 or higher. Solubility of saflufenacil was (1) 10.1 mg L−1 in water with a pH of 4.0, (2) 3,461.4 mg L−1 in water with a pH of 7.7, and (3) > 5,000 mg L−1 at a pH of 9. Some degradation of parent saflufenacil was detected in the pH at 9.0 treatment, with only 90% of added product being recovered after 3 d of storage. This research provides information on how saflufenacil efficacy and solubility is influenced by carrier water pH and potentially explains some differences noticed between field applications of saflufenacil.

Greenhouse and field studies were conducted to evaluate bell pepper tolerance to the sulfonylurea herbicides imazosulfuron and thifensulfuron-methyl. Imazosulfuron was applied at 56, 112, 224, 336, or 448 g ai ha−1. Thifensulfuron-methyl was applied at 2.6, 5.3, 10.5, 21.0, or 31.6 g ai ha−1. In the greenhouse over 2 yr, bell pepper injury due to imazosulfuron POST ranged from 12 to 27%. Reductions in plant height and numbers of nodes, buds, flowers, and fruits were generally minor or not observed. Injury from thifensulfuron-methyl POST ranged from 40 to 60% in the greenhouse. Similar trends were observed for leaf chlorosis and distortion. Thifensulfuron-methyl tended to decrease numbers of buds, flowers, and fruits in the greenhouse. In the field at three sites, bell pepper injury due to imazosulfuron applied POST-directed (POST-DIR) was less than 10% at all rating times, and height and yield were not affected. Total and marketable yield averaged 40,300 and 35,810 kg ha−1, respectively, across environments and years. Bell pepper injury from thifensulfuron-methyl applied POST-DIR in the field was less than 20% with all rates and less than 10% when rates less than 10.6 g ai ha−1 thifensulfuron-methyl were applied. Bell pepper stand (plants ha−1) or height was not affected by thifensulfuron-methyl. Thifensulfuron-methyl did not affect total bell pepper yield (39,310 kg ha−1 averaged across environments); however, reductions in Fancy grade yield were observed. No. 1 and cull yield grades tended to increase with increasing thifensulfuron-methyl rate, apparently compensating for lost Fancy yield.

Crop interference and weed-competitive cultivars are a component of integrated weed management, but their use requires understanding the extent to which rice can interfere with weed growth and how weeds may respond to rice interference. Growth of blistering ammannia was studied in a screen house by growing it alone or with rice seeded in rows (20 cm) or broadcast at the rate of 25 and 75 kg ha−1. The growth of blistering ammannia was similar whether grown with rice seeding rates of 25 or 75 kg ha−1 or with broadcast or row-seeded rice, suggesting that the weed is a weak competitor if rice is planted uniformly. Rice interference greatly reduced the number of blistering ammannia leaves and leaf, stem, total shoot, and root biomass. However, the weed showed the ability to reduce the effects of rice interference by increasing leaf and stem biomass in the upper half of the plant, and increasing specific stem length. At 11 wk after planting, blistering ammannia had 71 to 80% leaf biomass in the upper half of the plant when grown with rice interference compared with only 29% when grown without rice interference. Despite such plasticity, blistering ammannia shoot and root biomass at final harvest decreased by 94 to 99% when grown with rice compared with its biomass without crop interference. These results suggest that blistering ammannia is a poor competitor and uniform rice density could be very effective in suppressing blistering ammannia in direct-seeded rice systems.

Weed control in Florida citrus is primarily based on herbicides. Saflufenacil, a POST-applied herbicide is recently registered for broadleaf weed control in citrus. Saflufenacil has very limited grass activity; therefore, it should be tank mixed with graminicides or broad-spectrum herbicides to increase the spectrum of weed control. Greenhouse and field experiments were conducted at two locations (Polk County and Orange County, FL) to evaluate the efficacy and potential antagonism or synergy of saflufenacil and sethoxydim applied alone or tank mixed, and various two- and three-way mixes with glyphosate or pendimethalin. The results suggested that tank mixing saflufenacil and sethoxydim had neither synergistic nor antagonistic effect on broadleaf and grass weed control, respectively. Tank mixing pendimethalin with saflufenacil and sethoxydim improved broadleaf and grass weed control and reduced weed density and biomass, compared with saflufenacil or sethoxydim applied alone or tank mixed at 45 and 60 d after treatment (DAT). Glyphosate tank mixed with saflufenacil and sethoxydim provided > 90% control of broadleaf and grass weeds at 15 DAT, reduced density ≤ 8 plants m−2, and reduced biomass < 95 g m−2 at 60 DAT. Glyphosate applied alone was less effective than it was when tank mixed with saflufenacil and sethoxydim or pendimethalin for broadleaf and grass weed control, indicating an additive effect of tank mixture on glyphosate efficacy. It is concluded that saflufenacil can be tank mixed with sethoxydim for control of broadleaf and grass weeds without antagonism on the efficacy of either herbicide; however, tank mixing saflufenacil and sethoxydim with glyphosate or pendimethalin provided long-term, broad-spectrum weed control in Florida citrus.

Greenhouse studies were conducted in Raleigh, NC to determine Carolina redroot control by selected PRE and POST herbicides labeled for blueberries. Paraquat, glufosinate, glyphosate, and flumioxazin provided some Carolina redroot shoot control 7 d after POST application (DAPOST) ranging from 48 to 74%. Control 25 DAPOST was greatest for hexazinone at 2.2 kg ai ha−1 (90%) followed by glufosinate with 56% control and paraquat and terbacil each with 53% control. Control for most treatments declined between 25 and 63 DAPOST with the exception of glyphosate, which increased to 64%. Carolina redroot shoots per pot were reduced by terbacil, hexazinone at 2.2 kg ha−1, and glyphosate compared with the nontreated check 63 DAPOST. Control of Carolina redroot roots and rhizomes 63 DAPOST ranged from 7 to 68%, with the greatest control provided by terbacil (68%) and hexazinone at 2.2 kg ha−1 (64%). Terbacil and hexazinone at 2.2 kg ha−1 were the only treatments that reduced both shoot and root/rhizome dry weight compared with the nontreated check.

Greenhouse studies were conducted in 2012 in Raleigh, NC to determine Carolina redroot control by ten POST herbicides. Paraquat and glufosinate provided the greatest control 14 (73 and 64%, respectively) and 25 d (82 and 68%, respectively) after treatment (DAT), but control declined between 25 and 63 DAT (72 and 59%, respectively). Glyphosate provided minimal control 14 DAT (18%), and control increased from 14 to 25 DAT (46%) and 25 to 63 DAT (69%). Control of Carolina redroot roots and rhizomes (roots/rhizomes) was greatest in plants treated with paraquat (91%), glyphosate (88%), glufosinate (73%), hexazinone (62%), diuron (60%). Nontreated Carolina redroot shoot and root/rhizome dry weight were 8.3 and 7.6 g, respectively. Paraquat, glufosinate, glyphosate, and diuron reduced both shoot and root/rhizome dry weight (3.1 and 0.7 g, 5.1 and 2.7 g, 5.4 and 1.0, 5.7 and 1.6 g, respectively). Hexazinone reduced root/rhizome dry weight (2.7 g). Fomesafen reduced shoot dry weight (6.1 g), but did not reduce root/rhizome dry weight. Paraquat, glufosinate, glyphosate, hexazinone, diuron, and clopyralid treatments resulted in reduced incidence of Carolina redroot flowering and anthesis.

Potatoes are an important global food crop typically produced in high-input systems in temperate zones. Growers that have access to compost may use it to improve soil health and increase tuber yields, but compost may also increase weed competition by increasing early-season water availability and weed growth. A field study at the Michigan State University Montcalm Research farm in 2010 and 2011 investigated the impact of compost on weed competition in potato. Potatoes were grown in field plots with 0, 4,000, or 8,000 kg carbon (C) ha−1 of compost under weed-free conditions, and in competition with common lambsquarters, giant foxtail, and hairy nightshade. Compost did not increase biomass or seed production of any weed species. Giant foxtail and hairy nightshade at 5.3 plants per meter of row reduced potato yield by 20%; common lambsquarters reduced yield by 45%. The yield reduction by giant foxtail and hairy nightshade was due to a decrease in tuber bulking, whereas yield reductions from common lambsquarters were a result of lower tuber set and bulking. Potato yield increased 5 to 15% in compost compared to non-compost treatments; tuber specific gravity decreased by 0.3% in composted treatments. Across weed densities, elevated soil potassium levels in the 8,000 kg C ha−1 composted treatment may have increased potato yield and decreased tuber specific gravity.

Common bermudagrass is a problematic weed within tall fescue turfgrass. Field research was conducted from 2010 to 2012 in Knoxville, TN, evaluating the efficacy of sequential applications of topramezone (12.5 and 25 g ha−1), triclopyr (1,120 g ha−1), and mixtures of topramezone + triclopyr for bermudagrass control in tall fescue turf. Sequential applications of fenoxaprop + triclopyr (100 + 1,120 g ha−1) were included for comparison. Three applications of each treatment were applied at 21-d intervals during July, August, and September of 2010 and 2011. Plots were stripped to receive tall fescue interseeding at 0 or 490 kg ha−1 during September 2010 and 2011. Bermudagrass control with topramezone + triclopyr mixtures was greater than topramezone or triclopyr applied alone 14 wk after initial treatment (WAIT) each year. In the second year of this study, topramezone + triclopyr mixtures controlled bermudagrass 27 to 50% compared to 27% for fenoxaprop + triclopyr by 52 WAIT. However, bermudagrass control with topramezone + triclopyr mixtures increased to 88 to 92% by 52 WAIT when accompanied with tall fescue interseeding at 490 kg ha−1. Future research should evaluate effects of interseeding on the efficacy of different herbicides for weed control in cool- and warm-season turf.

Bermudagrass is grown extensively in the southern United States as a livestock forage. Annual grass weeds can be problematic in bermudagrass hay production, few effective control measures are available. Bermudagrass hay is harvested approximately every 28 d. Because most annual grass weeds germinate whenever environmental conditions become appropriate, control options must address a target weed population that varies in age, and may or may not have been mowed during previous harvests. Cohort age has rarely been included in control studies that combine herbicides and mowing. We tested this idea in a greenhouse study. Barnyardgrass, large crabgrass, and green foxtail were seeded on a weekly schedule. The following four treatments were initiated when five cohort ages ranging 8 to 36 d were obtained: clipping only, herbicide only, clipping followed by (fb) herbicide, and a nontreated control. Time interval between clipping and herbicide application was 5 d. Plants were clipped at 5 cm above the soil surface. Herbicide application was a tank mixture of nicosulfuron + metsulfuron at 39.3 + 10.5 g ai ha−1, respectively. Shoots were harvested 21 d after the herbicide treatment, and dry weights of the first three treatments were expressed as percent biomass reduction relative to the age-equivalent nontreated control. Regression analyses indicated a similar response pattern for all three grass species within treatments. For clipping alone, biomass reduction increased as cohort age increased. Conversely for herbicide alone, biomass reduction decreased with age. However, biomass reduction with the clipping fb herbicide treatment was only nominally influenced by grass cohort age, providing ≥ 84% biomass reduction across all cohort ages and species.

A written survey administered to 3,500 Florida cattle producers in 2006 documented tropical soda apple as the most common pasture weed across the state of Florida. Over 80% of the survey respondents reported tropical soda apple on their ranches, and over 65% declared the plant to be a major problem for their cattle operation. On ranches that reported tropical soda apple infestations, the level of pastures infested with this weed ranged from a low of 4% in north Florida to a high of 12% in central Florida. The cattle producers' most common strategies to tropical soda apple were herbicide application and mowing. These strategies were used by 32% of respondents in north Florida, 75% in central Florida, and 76% in south Florida. On a statewide basis, 20% of cattle producers used herbicides alone, 7% used mowing alone, and 20% used both methods. Some cattle producers reduced the cattle stocking rate as a consequence of tropical soda apple infestations. This negative impact was reported by only 2% of cattle producers in north Florida, 6% in central Florida, and 7% in south Florida. With the use of the economic input/output model IMPLAN, tropical soda apple control costs resulted in economic losses throughout Florida of $15 million annually in 2006 to cattle producers and their supporting business sectors.

Field studies were conducted in 2010 and 2011 at two locations in Michigan to examine the effect of row width and herbicide combination on weed suppression and yield in the new Type II black bean variety ‘Zorro.' Black bean was planted in 38- and 76-cm rows. Six weed control strategies were examined: S-metolachlor + halosulfuron (PRE), S-metolachlor (PRE) followed by (fb) bentazon + fomesafen (POST), halosulfuron (PRE) fb clethodim (+ fomesafen at one site in one year) (POST), imazamox + bentazon (POST), a weed-free control, and a nontreated control. Weed control and crop injury were evaluated throughout the growing season. In addition, weeds were counted by species in late July, and weed biomass was harvested and weighed at the end of the season. Black bean yield was obtained by direct harvest. Narrow rows reduced weed populations in two of the four site–year combinations (referred to hereafter as site–years), reduced weed biomass in three of the four site–years, and often improved control of upright broadleaf weeds. All herbicide combinations generally reduced weed populations and biomass, but control of specific weeds was variable. Crop injury was generally slight and transient. Yield was greater in narrow rows in two of the four site–years. All herbicide combinations increased yield compared with the nontreated control and resulted in similar yields to one another. Yield and weed suppression was often maximized in narrow rows, while herbicide performance varied by year and weed spectrum.

Vapor movement of synthetic auxin herbicides can injure desirable plants outside the treatment zone. Vapor movement of the synthetic auxin herbicides aminocyclopyrachlor and aminocyclopyrachlor methyl was compared with that of the relatively volatile herbicide dicamba and the low volatile herbicide aminopyralid with a soybean bioassay under greenhouse and field conditions. Soybean is very sensitive to these active ingredients. Under greenhouse conditions, 82 (61 to 104) mg ae ha−1 of aminocyclopyrachlor, 26 (18 to 33) mg ae ha−1 of aminocyclopyrachlor methyl, 82 (69 to 95) mg ae ha−1 of aminopyralid, and 61 (47 to 75) mg ae ha−1 of dicamba produced an estimated 25% visual soybean phytotoxicity response when soybean was treated POST at the V3 growth stage (GR25 [95% confidence interval]). In field studies, aminocyclopyrachlor, aminocyclopyrachlor methyl, and aminopyralid were applied at 70 g ae ha−1 and dicamba was applied at 560 g ae ha−1 (labeled application rates) to soybean at the V3 growth stage. All herbicides were applied within an enclosed chamber (3 m by 3 m by 1 m) to mitigate movement of spray droplets. The enclosures were removed shortly after spray application and soybean response immediately surrounding the treated area was recorded in each of eight directions approximately 10 d after treatment. On the basis of bioassay responses, relative amount of vapor movement was dicamba > aminocyclopyrachlor methyl > aminopyralid ≈ aminocyclopyrachlor. Vapor movement of aminocyclopyrachlor was very low indicating that the risk of phytotoxic response of sensitive plants due to volatility of aminocyclopyrachlor is negligible.

Research was conducted in 2003 and 2004 to evaluate diflufenzopyr tank mixes for western ragweed control and injury to ‘Tifton 85′ bermudagrass. In 2003 at 94 DAT, picloram at 0.28 and 0.56 kg ae ha−1 with or without diflufenzopyr provided greater than 95% control of western ragweed, whereas triclopyr + dilfufenzopyr, dicamba + diflufenzopyr, triclopyr alone, and diflufenzopyr alone provided < 77% control. In 2004 at 95 DAT, only the highest rate of picloram alone provided 96% control, and the two highest rates of picloram + diflufenzopyr provided at least 95% control. Tifton 85 bermudagrass growth reduction increased with the addition of diflufenzopyr to picloram in 2003, but not in 2004. However, forage dry-matter yield was not reduced by any herbicide treatment compared to the nontreated control. Results of these studies indicate that picloram alone and picloram + diflufenzopyr provide excellent control of western ragweed. The tank mixture of picloram + diflufenzopyr can improve control over picloram alone. However, dicamba + diflufenzopyr, triclopyr + diflufenzopyr, triclopyr alone, and diflufenzopyr alone did not provide adequate control.

Students studying weed science would expand their knowledge by conducting targeted experiments on invasive weeds. Tamarix spp., some of the most problematic weeds known in the United States, have value for weed science education. Tamarix was used in an undergraduate laboratory course to demonstrate weed science principles for a minimal cost and with great potential for academic enhancement. The laboratory exercise was designed to teach weed science students about the difficulty associated with controlling invasive weeds even at a relatively young age in a region where plants have been detected but large-scale invasion has not occurred to emphasize the importance of early detection and rapid response. The successful execution of this exercise and the positive student response suggests that Tamarix and other weeds with similar reproductive capacities could be valuable additions to weed science curricula. Innovative approaches to teaching weed science facilitate greater learning of this complex subject by students from diverse backgrounds and academic disciplines.

PRE herbicides have been reported to injure both the foliage and roots of hybrid bermudagrass turf established in sand culture. Research was conducted to evaluate the influence of reed-sedge peat moss (RSPM) on hybrid bermudagrass injury following PRE herbicide applications to plants established in sand culture. Washed sod plugs were established in mini-rhizotrons constructed with sand root-zones varying in organic carbon content (0.000, 0.003, 0.007, and 0.012 kg kg−1). Herbicide treatments included indaziflam (35 and 52.5 g ai ha−1) and prodiamine (840 g ai ha−1). Significant foliar injury was only observed with indaziflam at 52.5 g ha−1. When applied to plants in sand with no detectable (0.000 kg kg−1) organic carbon, foliar injury measured 61% by 6 wk after treatment. Comparatively, injury with indaziflam at 52.5 g ha−1 was reduced by 40% with applications to plants established in sand with 0.007 kg kg−1 organic carbon. Root length, root length density, and root surface area were greatest in sand-based root zones with ≥ 0.007 kg kg−1 organic carbon regardless of herbicide treatment; however, only indaziflam (52.5 g ha−1) and prodiamine-treated plants exhibited diminished root parameters relative to the nontreated check. Data in the current study illustrate that RSPM can affect above- and belowground injury following PRE herbicide applications to hybrid bermudagrass in sand root-zones.