Clomazone was labeled for rice in 2001; however, that label excluded its use on coarse- (light) textured soils, including sand, loamy sand, and sandy loam with less than 1% organic matter due to rice injury. Field studies conducted in 2005, 2006, and 2007 evaluated weed control and tolerance of rice to early postemergence (EPOST) applications of clomazone alone and tank mixed with other herbicides on sandy loam and clay loam soils. At 42 d after treatment (DAT), broadleaf signalgrass (BRAPP) and barnyardgrass (ECHCG) control was > 86%. At 14 DAT, rice injury was greatest (13%) from clomazone applied preemergence (PRE) at 0.44 kg ai/ha on sandy soil. Annual sedge (CYPCP) control was > 78% on sandy loam soils at 14 DAT, but increased to > 90% by 42 DAT. On clay loam soils, CYPCP control at 42 DAT ranged from 60 to 76% from clomazone alone or tank mixed with cyhalofop or fenoxaprop. All other tank mixes provided > 80% control. Hemp sesbania (SEBEX) control was > 80% from all tank mixes. Clomazone alone provided < 77% control. Data suggest that clomazone can be used EPOST in combination with other herbicides without causing significant rice injury on sandy loam soils in Texas.

Rice was planted at 78 kg/ha with different densities of creeping rivergrass. Creeping rivergrass at stand densities (SD) of 10,000 to 70,000 stolon segments/ha produced 5.4 to 6 stolons per introduced segment; however, 130,000 through 520,000 SD produced 1.4 to 2.1 stolons per segment. Stolon production was 60,000 plants/ha and increased to 760,000 stolons/ha at planting densities of 10,000 to 520,000/ha, respectively. The 260,000 and 520,000 SD produced similar stolon lengths of 217 and 318 km/ha; however, stolon length was less at lower SD. Total node production was 290,000 nodes per ha with an average of 29 nodes per segment in the 10,000 SD and 5.4 to 9.8 nodes per segment with 70,000 or greater SD. Total biomass increased as SD increased. Creeping rivergrass shoot emergence from soil was 31, 63, 44, and 25% for segments planted at 0, 1.3, 2.5, and 5 cm deep, respectively. In a greenhouse study, glyphosate at 1,260 g ai/ha controlled creeping rivergrass 91% and biomass production was 19% of the nontreated creeping rivergrass. Bispyribac, cyhalofop, fenoxaprop/s, fenoxaprop/s plus fenoxaprop, glufosinate, imazethapyr, penoxsulam, propanil, and quinclorac were less effective than glyphosate.

Field and greenhouse studies were conducted to evaluate mesotrione alone and in combinations with low rates of atrazine and bentazon for control of yellow and purple nutsedge. Mesotrione alone at rates of 105 to 210 g ai/ha controlled yellow nutsedge 43 to 70%. Mixtures of mesotrione with atrazine at 280 g ai/ha did not always improve yellow nutsedge control over that by mesotrione alone, but increasing atrazine to 560 g ai/ha in these mixtures generally provided more consistent control of yellow nutsedge. Mesotrione at 105 g ai/ha mixed with bentazon at 280 or 560 g ai/ha controlled yellow nutsedge 88% or greater which was similar to control from the standard halosulfuron at 36 g ai/ha. Mesotrione, atrazine, and bentazon alone did not control purple nutsedge. Mixtures of mesotrione plus bentazon, however, did improve control of purple nutsedge over either herbicide applied alone, but this control was not considered commercially acceptable.

Studies were conducted at three locations in North Carolina in 2004 to evaluate density-dependent effects of glufosinate-resistant (GUR) corn on GUR cotton growth and lint yield. GUR corn was taller than GUR cotton as early as 11 d after planting, depending on location. A GUR corn density of 5.25 plant/m of crop row reduced late-season cotton height by 38, 43, and 43% at Clayton, Lewiston-Woodville, and Rocky Mount, NC, respectively, compared with weed-free cotton height. GUR corn dry biomass per meter of crop row and GUR corn seed biomass per meter of crop row decreased linearly with increasing GUR corn density at all locations. The relationship between GUR corn density and GUR cotton yield loss was described by the rectangular hyperbola model with the asymptote (a) constrained to 100% maximum yield loss. The estimated coefficient i (yield loss per unit density as density approaches zero) was 7, 5, and 6 at Clayton, Lewiston-Woodville, and Rocky Mount, respectively. Percentage of GUR cotton lint yield loss increased 4, 5, and 8 percentage points at Clayton, Lewiston-Woodville, and Rocky Mount, respectively, with each 500 g increase in weed biomass/m of crop row. The examined GUR corn densities had a significant effect on cotton yield but not as significant as many other problematic grass and broadleaf weeds.

It has been suggested that trifloxysulfuron might increase the efficacy of asulam for control of johnsongrass. Container and field studies were conducted to determine the efficacy of POST applications of trifloxysulfuron and asulam for johnsongrass control in sugarcane. Asulam was applied at 460 and 920 g ai/ha to container-grown johnsongrass plants, with and without 8 g ai/ha of trifloxysulfuron. Combinations of asulam and trifloxysulfuron generally reduced johnsongrass height, rhizome length, and biomass more than when either was applied alone. Results suggested that combinations of asulam and trifloxysulfuron were synergistic in their control of johnsongrass biomass 8 wk after treatment. In a sugarcane field heavily infested with rhizome johnsongrass, asulam was applied at 1,800, 2,800, and 3,700 g/ha with and without trifloxysulfuron at 16 g/ha. Asulam plus trifloxysulfuron generally controlled johnsongrass more effectively than either herbicide alone. The control of johnsongrass with asulam at 1,800 g/ha resulted in an increase in sugar yield of more than twice that in the nontreated control. Sugar yield increased further when asulam was applied at 2,800 g/ha or combined with trifloxysulfuron, but application of trifloxysulfuron alone did not increase yield. Combinations of asulam and trifloxysulfuron might slow the spread of rhizome johnsongrass enough to allow an increased number of ratoon crops before sugarcane fields need to be replanted.

Aquatic plants provide many benefits to the environment, but must be managed when growth reaches nuisance levels or when invasive plant species are released. Management tactics include biological, chemical, cultural, mechanical, and physical tools. Each specific management technique has advantages and disadvantages. In addition, the implementation of these techniques can become complicated because of the multiple users, managers, and stakeholders that may be present on large bodies of water. As an example, hydrilla is the most economically damaging aquatic weed in the United States. It reproduces through fragmentation, turions, and occasionally seed and can colonize a wide variety of aquatic environments. The most common management tactics for hydrilla include biological, chemical, and mechanical tools. Triploid grass carp have been the primary biological control agent, whereas fluridone has been the only systemic herbicide used. Because of heavy utilization of fluridone, biotypes have developed resistance to this herbicide in Florida. Although several acetolactate synthase-inhibiting herbicides are in development, herbicides with additional modes of action are needed for resistance management. Other aquatic plant management needs include additional control tactics for algae and additional extension resources for public education.

Experiments were conducted at three North Carolina research stations in 2003 to evaluate weed control and corn yield in glyphosate-resistant, glufosinate-resistant, imidazolinone-tolerant, and conventional corn weed management systems. Late-season control of common lambsquarters, large crabgrass, and yellow nutsedge increased with metolachlor PRE compared with no PRE herbicide treatment. Common lambsquarters, pitted morningglory, entireleaf morningglory, spurred anoda, and tropic croton control was improved by a single early POST (EPOST) application regardless of herbicide system. Control of common lambsquarters, pitted morningglory, entireleaf morningglory, and spurred anoda was similar for glyphosate and glufosinate systems for each POST over-the-top (POT) herbicide system. A single EPOST application of imazethapyr plus imazapyr to imidazolinone-tolerant corn controlled common lambsquarters, pitted morningglory, entireleaf morningglory, and spurred anoda and was better than a single EPOST application of glyphosate, glufosinate, or nicosulfuron. Tropic croton was controlled ≥ 95% with glufosinate or glyphosate, applied once or twice, or in mixture with metolachlor. A single EPOST application of imazethapyr plus imazapyr or nicosulfuron did not control tropic croton. Common lambsquarters, entireleaf morningglory, large crabgrass, Palmer amaranth, and yellow nutsedge control was greater with a late-POST–directed (LAYBY) of ametryn than no LAYBY. Systems that did not include a POT herbicide system had the lowest percentage in the weed-free yield and the lowest yield. Treatments that included a POT system with or without a PRE treatment of metolachlor yielded within 5% of the weed-free treatment, regardless of herbicide system.

Research on weed management in furrow-irrigated rice is needed as water availability becomes more limited in rice production regions of Arkansas. Research was conducted at Keiser and Pine Tree, AR, with the objectives being to determine (1) whether the addition of clomazone to imazethapyr would improve PRE weed control in furrow-irrigated, imidazolinone-tolerant rice, and (2) whether increasing the imazethapyr rates would improve weed control without injuring rice. Imazethapyr was applied at 70, 87.5, and 105 g ai/ha PRE with and without clomazone followed by imazethapyr POST at the same rate as used PRE. No rice injury was observed during the growing season at either site. Clomazone plus imazethapyr applied PRE did not improve early season control of Palmer amaranth, pitted morningglory, prickly sida, barnyardgrass, or broadleaf signalgrass over imazethapyr alone. Increasing the PRE imazethapyr rate to 105 g/ha did not improve Palmer amaranth or pitted morningglory control. Imazethapyr applied PRE on a clay soil generally provided lower weed control than on the silt loam soil. Increasing the imazethapyr rate did not improve rice yields.

Experiments were conducted from 2003 through 2006 to compare annual grass control by graminicides applied alone or with other pesticides and to determine whether graminicide formulation affected annual grass control and interactions with co-applied pesticides. Formulation and rate had no affect on broadleaf signalgrass or large crabgrass control by clethodim. The efficacy of clethodim in tank mixtures with acifluorfen plus bentazon, bentazon, chlorothalonil, imazapic, pyraclostrobin, or tebuconazole were not affected by clethodim formulation. Broadleaf signalgrass and large crabgrass control by clethodim was slightly reduced by acifluorfen plus bentazon, chlorothalonil, imazapic, and pyraclostrobin, but not by tebuconazole. Chlorothalonil and pyraclostrobin reduced broadleaf signalgrass control with quizalofop-P but did not reduce fall panicum control. Azoxystrobin, propiconazole, and tebuconazole did not affect efficacy of quizalofop-P.

Research was conducted to evaluate residual activity of herbicides applied postemergence (POST) and preemergence (PRE) for red morningglory control. Atrazine at 2.24 kg ai/ha controlled 30- to 60-cm red morningglory 78% 10 d after treatment (DAT) but control was greater for carfentrazone at 0.035 kg ai/ha, diuron plus hexazinone at 1.57 + 0.44 kg ai/ha, flumioxazin at 0.14 kg ai/ha, and sulfentrazone at 0.32 kg ai/ha (88 to 93%). At 28 DAT control with diuron plus hexazinone, flumioxazin, and sulfentrazone, reflective of both the initial POST control and soil residual activity, was equivalent to that of atrazine at 3.36 kg/ha (92%), but control was 34 to 66% with carfentrazone at 0.009, 0.018, and 0.026 kg/ha, hexazinone at 0.56 kg/ha, pyraflufen at 0.007 and 0.015 kg ai/ha, and trifloxysulfuron at 0.016 kg ai/ha. In another study to evaluate residual control with soil-applied herbicides, red morningglory was controlled at least 87% 35 DAT with atrazine at 2.24 kg/ha, diuron plus hexazinone at 1.57 + 0.44 kg/ha, flumioxazin at 0.14 kg/ha, sulfentrazone at 0.16 kg/ha, and metribuzin at 1.68 kg ai/ha. Control 35 DAT was 78% for atrazine at 1.12 kg/ha, 84% for diuron plus hexazinone at 1.05 + 0.30 kg/ha, and 63% for flumioxazin at 0.07 kg/ha. By 49 DAT only sulfentrazone controlled red morningglory 80% or more and by 63 DAT, control with sulfentrazone at rates of 0.21 kg/ha and higher was 83 to 88%. At 77 DAT sulfentrazone at 0.21 kg/ha controlled red morningglory 78% and no other herbicide treatment provided more than 46% control. In another study red morningglory control did not change from 49 to 63 DAT when sulfentrazone at 0.28 to 0.42 kg/ha was applied PRE following trifluralin preplant incorporated (PPI), but control decreased from 49 to 63 DAT when sulfentrazone was incorporated with trifluralin.

Experiments were conducted in the greenhouse and the field to evaluate the efficacy of various sulfonylurea herbicides applied with mesotrione or mesotrione + atrazine. The addition of mesotrione or mesotrione + atrazine to sulfonylurea herbicides had no adverse effects on the control of large crabgrass or velvetleaf in a controlled environment. Tank mixing mesotrione or mesotrione + atrazine with nicosulfuron or foramsulfuron, however, antagonized nicosulfuron and foramsulfuron control of green foxtail and shattercane. Field experiments conducted in 2004 and 2005 also indicated that addition of mesotrione + atrazine to a sulfonylurea herbicide decreased herbicidal efficacy on green foxtail, yellow foxtail, and shattercane, compared with the sulfonylurea herbicide applied alone. In addition, increasing mesotrione application from 53 to 105 g/ha decreased efficacy of sulfonylurea herbicide in the tank mix on selected grass species. This research showed that the addition of mesotrione to sulfonylurea herbicides resulted in decreased efficacy of sulfonylurea herbicides on green foxtail, yellow foxtail, and shattercane. The addition of atrazine to the tank mix or an increased mesotrione rate will further decrease herbicide efficacy of sulfonylurea herbicides on shattercane and foxtail species.

Field studies were conducted in 2005 and 2006 to determine the most effective chemical options within three individual herbicide-based burndown programs, glyphosate, paraquat and glufosinate, for controlling glyphosate-resistant horseweed in Mississippi. Burndown treatments were applied April 5, 2005 and March 15, 2006 to horseweed plants 15 to 30 cm in height. Glyphosate at 0.86 kg ae/ha alone provided 60 to 65% horseweed control 4 wk after treatment (WAT). Control 4 WAT ranged from 73 to 74% when the glyphosate rate was increased to 1.25 kg/ha. Glyphosate at 0.86 kg/ha applied in combination with 2,4-D at 0.84 kg ae/ha or dicamba at 0.28 ae/ha maximized control of horseweed (≥ 90%) 4 WAT and soybean yield. Horseweed control 4 WAT with paraquat alone at 0.84 kg ai/ha ranged from 55 to 63% and control did not improve by increasing the rate to 0.98 kg/ha. Addition of 2,4-D or dicamba to paraquat maximized horseweed control both years (78 to 89%), whereas soybean yield was maximized with addition of dicamba or metribuzin at 0.42 kg ai/ha. Glufosinate applied alone at 0.47 kg ai/ha resulted in at least 88% control of horseweed and maximized soybean yield. Results indicate that effective management of glyphosate-resistant horseweed can be obtained in glyphosate-resistant soybean in glyphosate-, paraquat-, and glufosinate-based preplant weed control programs.

Peanuts are not often used as a true oilseed crop, especially for the production of fuel. However, peanut could be a feedstock for biodiesel, especially in on-farm or small cooperative businesses, where producers can dictate the cost of making their own fuel. Field studies were conducted in 2005 and 2006 to assess low-cost weed-control systems for peanuts that would facilitate the economic viability of peanut biodiesel. Four preselected herbicide costs ranging from $25 to $62/ha and two application timings were compared with nontreated ($0/ha) and typical ($115/ha) herbicide programs for weed control and peanut oil yield. A peanut oil yield goal of 930 L/ha was exceeded with multiple low-cost herbicide systems in 3 of 4 site–yr. The main effect of application timing was only significant for a single site–year in which oil yield increased linearly with cost of the PRE and POST weed-control system. An herbicide cost of $50/ha, using PRE and POST applications, was consistently among the highest in oil yield, regardless of site–year, exceeding the typical (high value) programs in 3 of 4 site–yr. Use of reduced rates of imazapic (0.5× or 0.035 kg ai/ha) was detrimental in 2 of 4 site–yr. Weed control, and thus oil yields, were most dependent on species present at each location and not on input price. Data from this series of studies will allow researchers and entrepreneurs to more accurately assess the viability and sustainability of peanut biodiesel.

Glyphosate-resistant alfalfa offers new weed control options for alfalfa establishment. Field studies were conducted in 2004 and 2005 to determine the effect of establishment method and weed control method on forage production and alfalfa stand establishment. Seeding methods included clear seeding and companion seeding with oats. Herbicide treatments included glyphosate, imazamox, imazamox + clethodim, and no herbicide. Temporary stunting from the glyphosate treatments was observed (< 7%); however, injury did not reduce forage yield or stand density in 2004. No glyphosate injury was observed in 2005. Weed control with glyphosate was more consistent than with imazamox or imazamox + clethodim. In 2004, total seasonal forage yield, which consisted of alfalfa, weeds, and oats (in some treatments), was the highest where no herbicide was applied in the oat companion crop and was reduced where herbicides were applied in both establishment systems. In 2005, seeding method or weed control method did not affect total seasonal forage production. Alfalfa established with the clear-seeded method and treated with glyphosate yielded the highest alfalfa dry matter in both years. Imazamox injury reduced first-harvest alfalfa yield in the clear-seeded system in both years. When no herbicide was applied, alfalfa yield was higher in the clear-seeded system. The oat companion crop suppressed alfalfa yield significantly in both years. Alfalfa established with an oat companion crop had a lower weed biomass than the clear-seeded system where no herbicide was applied in both years.

Palmer amaranth accessions were collected from 21 fields in northeastern Arkansas in the fall of 2006 to determine if they differed in response to increasing doses of glyphosate and to determine the survival frequency following treatment with the label rate (870 g ae/ha). The herbicide dose required to kill 50% of individuals in an accession (LD50) ranged from 41 to 339 g/ha glyphosate, with most accessions responding similarly to glyphosate. The AR18 and AR19 were the least-sensitive accessions, with LD50 rates of 312 and 339 g/ha glyphosate, respectively. The mean survival frequency was 2.2% across all accessions when 870 g/ha glyphosate was applied to five- to seven-leaf plants. Sixteen of the accessions had at least one plant survive glyphosate at 870 g/ha. AR18 and AR19 accessions had a survival frequency of 6.3 and 11.8%, respectively. Following an additional cycle of selection with glyphosate, 44.3% of the progeny from the AR19 accession survived glyphosate at 870 g/ha, and its LD50 value significantly increased to 646 g/ha glyphosate. This research shows that there is a low percentage of Palmer amaranth plants currently present in production fields throughout northeastern Arkansas that are capable of surviving a single glyphosate application at the labeled rate and that further selection with glyphosate can increase the frequency of survival.

Pesticide bans in Canada have resulted in a requirement for municipal turfgrass managers to use cultural methods of weed control to provide a safe playing surface for athletes. A field study was conducted to determine if overseeding provides enough competition to decrease weed populations in Kentucky bluegrass athletic turf typically used in municipal parks for recreation. Perennial ryegrass was overseeded at 2, 4, and 8 kg/100 m2 in May, July, or September, and all permutations of these timings in nonirrigated and irrigated trials at the Guelph Turfgrass Institute (GTI) field station in Guelph, and on in-use soccer fields at the University of Guelph campus and in the town of Oakville, Ontario, Canada over 2 yr. Plant cover by species was recorded every other month using a randomized point quadrat method throughout the growing seasons of 2005 and 2006. Weed populations were not affected by overseeding in 2005, a dry growing season. However, when weed populations were high and normal growing conditions existed in 2006, overseeding applications in May/July/September at 4 and 8 kg/100 m2 decreased perennial weed cover, specifically white clover in the irrigated trial and dandelion in the nonirrigated trial at the GTI. An increase in perennial ryegrass was observed in all plots that received an overseeding treatment. Treatments applied on the in-use soccer fields in Oakville and Guelph, which included May/September and May only overseedings, had no effect on weed populations or perennial ryegrass populations compared to the weedy control. Over the short term, high-rate and frequent overseeding with perennial ryegrass appears to provide competition against perennial weeds when weed cover is high and should be considered an important part of a weed management program for municipal turfgrass managers.

Field studies were conducted near Knoxville, TN, from 2003 to 2005 to evaluate the response of ‘Thermal Blue’, a new interspecific hybrid Kentucky bluegrass to commonly applied PRE and POST herbicides for weed management. Dithiopyr, oryzalin, oxadiazon, pendimethalin, prodiamine, quinclorac, and trifluralin applied at seeding injured hybrid bluegrass greater than 81% and reduced hybrid bluegrass cover greater than 57%. In a second study, established hybrid bluegrass was treated POST with acetolactate synthase–inhibiting herbicides including bispyribac-sodium, chlorosulfuron, foramsulfuron, halosulfuron, imazapic, imazaquin, metsulfuron, rimsulfuron, sulfosulfuron, and trifloxysulfuron at low and high rates (one and two times the suggested use rates in Kentucky bluegrass or other turfgrasses). By 5 wk after treatment (WAT), foramsulfuron at 88 g ai/ha and trifloxysulfuron at 35 g ai/ha injured hybrid bluegrass greater than 26% and reduced visually estimated quality and chlorophyll meter indices. However, hybrid bluegrass injury was no longer evident at 10 WAT. In a third study, established hybrid bluegrass was treated with clethodim, diclofop-methyl, fluazifop-p-butyl, and sethoxydim applied at low, medium, and high rates (0.5, 1, and 2 times the registered Kentucky bluegrass or other turfgrass use rates). Clethodim applied at 280 and 560 g ai/ha, fluazifop at 420 g ai/ha, and sethoxydim at 630 g ai/ha injured hybrid bluegrass 5 WAT. These treatments also reduced quality (to less than 5 on a scale of 1 to 9) and chlorophyll meter indices (24 to 37%) when compared to the untreated control. By 10 WAT, only clethodim at 560 g ai/ha caused injury (14%). By 10 WAT, hybrid bluegrass had recovered and injury was only observed in plots treated with clethodim at 560 g ai/ha. No differences in chlorophyll indices or quality were observed at 10 WAT for any POST graminicides.

Alfalfa–orchardgrass hay is popular in the Western United States because of an expanding horse-hay market. However, weed control in mixed alfalfa–orchardgrass stands is problematic, as herbicides must be safe for both species. Most growers rely solely on the competitiveness of the crop for weed control, which is often insufficient, especially in older stands. Field experiments were established in northern California to determine the efficacy and crop safety of several herbicides for winter annual weed control in established alfalfa–orchardgrass. Metribuzin at 560 or 840 g/ha and hexazinone at 420 g/ha applied in late fall provided at least 95% control of shepherd's purse and at least 80% control of downy brome without crop injury. Imazethapyr at 70 g/ha applied shortly after crop green-up provided more than 85% control of emerged mustards without crop injury. Paraquat at 560 g/ha applied shortly after crop green-up gave 50 to 82% weed control and caused significant injury to orchardgrass, which was still noticeable at first cutting.

Field experiments were conducted in 1999 and 2000 to evaluate early POST (EPOST) and late POST (LPOST) control of common ragweed and giant foxtail with mesotrione at 70, 105, and 140 g ai/ha alone and in mixtures with glufosinate at 300 g ai/ha in glufosinate-resistant corn. Glufosinate-resistant corn injury was frequently higher with mixtures of mesotrione plus glufosinate than with mesotrione applied alone. Mixtures of mesotrione with glufosinate applied EPOST injured corn 6 to 21% in 1999, but in 2000, injury from mixtures was 23 to 30% from LPOST applications. Common ragweed control was above 77% with all treatments, which included 105 g/ha mesotrione. Giant foxtail control was higher at 76 to 78% by mixtures of mesotrione with glufosinate applied LPOST than by mesotrione alone. Corn yields were highest when glufosinate was included in treatments at either application timing. In the greenhouse, mixtures of mesotrione with glufosinate-injured glufosinate-resistant corn 11% or less, but corn biomass was reduced by 25% for the mixture of mesotrione at 105 g/ha plus glufosinate at 350 g/ha. Mixtures of mesotrione with glufosinate can be more effective than mesotrione alone but control of common ragweed and giant foxtail might not be commercially acceptable.

Experiments were conducted to evaluate sharppod morningglory control with postemergence herbicides used in cotton and to determine the influence of diuron on glyphosate efficacy. Glyphosate plus diuron was one of the most efficacious herbicide treatments in the field experiment, providing up to 78% control of 10- to 20-cm stem length sharppod morningglory. In growth-chamber experiments, mixtures of either 420 or 840 g ai/ha diuron plus glyphosate potassium salt at 840 g ae/ha were needed to significantly reduce sharppod morningglory biomass. Compared to published results with other Ipomoea spp. and field bindweed, sharppod morningglory absorbed more and translocated less glyphosate after 72 h. Retention of glyphosate in treated leaves increased when the glyphosate was mixed with 420 g/ha diuron. Mixture with 420 or 840 g/ha diuron reduced the concentration of glyphosate in roots; however, only 2% of glyphosate alone was translocated to the roots. These results indicate that the combination of glyphosate with diuron improves aboveground sharppod morningglory desiccation, but limits glyphosate translocation.