bluuebunny/crossref_metadata_2025 huggingface dataset:
Controlling Two Sprangletop (Leptochloaspp.) Species with Preemergence Herbicides
Authors: McCarty Lambert B. , Porter D. Wayne , Colvin Daniel L. , Shilling Donn G. , Hall David W.
Published: March 2018

Field and greenhouse studies were conducted to evaluate selected PRE-applied herbicides for sprangletop control. In greenhouse studies, oxadiazon and dithiopyr provided excellent (> 89%) red sprangletop (L. filiformis) control. Pendimethalin and metolachlor + atrazine provided good (80–89%) to excellent control for 6 mo and 2 mo during studies 1 and 2, respectively. Isoxaben and atrazine provided poor (< 70%) control during both greenhouse studies. In field studies, good to excellent bearded sprangletop (L. fascicularis) control followed dithiopyr, pendimethalin, metolachlor, and metolachlor + atrazine treatments. Dithiopyr at 0.8 kg ai/ha provided best (> 95%) sprangletop control throughout the 6-mo testing period. Under field conditions, control was inconsistent following oxadiazon with good to excellent control during one study and poor control in another study. Better or equal control than metolachlor + atrazine followed dithiopyr, pendimethalin, and metolachlor alone treatments. Oxadiazon also provided similar or better control than metolachlor+atrazine in three of four studies. Over all studies, dithiopyr provided best sprangletop control, followed by metolachlor, metolachlor + atrazine, pendimethalin, and oxadiazon. Isoxaben and atrazine treatments provided poorest or inconsistent sprangletop control.
Moisture Requirements and Host Specificity ofRhizoctonia solaniFrom Leafy Spurge (Euphorbia esula) in Nebraska
Authors: Yuen Gary Y. , Masters Robert A.
Published: March 2018

R230, an isolate ofRhizoctonia solanianastomosis group 5 from leafy spurge, caused root and crown rots on leafy spurge when inoculated via soil in greenhouse experiments. The fungus grew through soil over a wide range of matric potentials (–0.01 to −1 MPa). When applied to leafy spurge foliage, the fungus blighted young adventitious shoots, but not mature stems. Foliar infection required high relative humidity. Mycelial growth on plant surfaces stopped at below 92% relative humidity. Pathogenicity of R230 was not limited to leafy spurge. The fungus caused stem and foliar lesions on all crops tested (alfalfa, smooth bromegrass, corn, Kentucky bluegrass, soybean, tall fescue, and wheat) when plants were kept under high humidity. It reduced seedling emergence and survival in soybean, Kentucky bluegrass, and tall fescue. R230 also caused a foliar blight on spotted spurge. The potential for R230 to damage crops will limit application of the fungus to noncultivated areas and to sites where it is endemic.
Reducing Johnsongrass (Sorghum halepense) Interference in Corn (Zea mays) with Herbicides and Cultivation
Authors: Steckel Gregory J. , Defelice Michael S.
Published: March 2018

Field studies were conducted in 1990 and 1991 to evaluate johnsongrass control and interference in corn using combinations of nicosulfuron, EPTC + dichlormid, and cultivation. Nicosulfuron applied to 30-cm-tall rhizome johnsongrass provided greater control and corn yield than a later application to 60-cm-tall johnsongrass. Johnsongrass control and corn yield within the later nicosulfuron treatment were improved by a preplant application of EPTC. EPTC and/or cultivation alone provided less johnsongrass control and lower corn yield than nicosulfuron or handweeding.
Grass Control in Soybean (Glycine max) with Graminicides Applied Alone and in Mixtures
Authors: Vidrine P. Roy , Reynolds Daniel B. , Blouin David C.
Published: March 2018

Field studies were conducted to determine rhizomatous johnsongrass and barnyardgrass control with clethodim, quizalofop-P-ethyl, fluazifop-P, sethoxydim, fenoxaprop-ethyl, and quizalofop-P-tefuryl applied alone and with lactofen, imazaquin, chlorimuron, and fomesafen. Graminicides applied alone controlled johnsongrass and barnyardgrass 83 to 99%. Of the graminicides evaluated, clethodim was the most susceptible to decreased grass control in mixture with broadleaf herbicides. Imazaquin and chlorimuron were most antagonistic of the broadleaf herbicides toward the activity of graminicides. Clethodim mixed with imazaquin reduced johnsongrass control as much as 64% and mixed with chlorimuron reduced barnyardgrass control as much as 52%. Quizalofop-P-tefuryl was least affected by broadleaf herbicides and fomesafen was least antagonistic in mixture with graminicides.
Effect of Simulated Rainfall, Insecticide Formulation, and Insecticide Application Method on the Interaction between Nicosulfuron and Terbufos in Corn (Zea mays)
Authors: Diehl Kevin E. , Stoller Edward W.
Published: March 2018

Applications of both terbufos and nicosulfuron can result in a synergistic interaction that injures corn. Field studies were conducted at two Illinois locations in 1991 to determine the effect of insecticide formulation and application method on the serverity of this interaction. Terbufos, applied to the soil at planting, interacted with nicosulfuron applied postemergence to injure corn and reduce grain yield. In-furrow-applied terbufos caused a more injurious interaction to corn than terbufos placed in a surface band; the 15G formulation was more injurious than the 20CR formulation. Simulated rainfall timing experiments were conducted in 1992 and 1993 by treating corn with terbufos 15G and terbufos 20CR and applying rainfall (3.8 cm) 1, 7, or 14 d before nicosulfuron application. No visual injury or yield reductions were noted in corn treated with nicosulfuron alone. Terbufos 15G caused greater corn injury than did terbufos 20CR at each rainfall timing when sprayed with nicosulfuron. Corn injury and subsequent grain yield that can result from the interaction between nicosulfuron and terbufos was greater when simulated rainfall occurred 1 and 7 d before nicosulfuron application than when rainfall occurred 14 d before application.
Effect of MON-12037 on Purple (Cyperus rotundus) and Yellow (Cyperus esculentus) Nutsedge
Authors: Vencill William K. , Richburg John S. , Wilcut John W. , Hawf Larry R.
Published: March 2018

Greenhouse studies were conducted to determine the response of purple and yellow nutsedge to selective soil placement of 5 cm of soil treated with MON-12037 above and/or below the nutsedge tubers. MON-12037 at 53 g/ai ha applied as a foliar, soil, or foliar + soil application also were evaluated. MON-12037 placement above, below, or above + below the nutsedge tuber decreased shoot number, shoot dry weight, shoot regrowth dry weight, and root-tuber dry weight production in both species, 30 and 60 d after treatment. MON-12037 applied as a foliar, soil, and foliar + soil treatment was effective in reducing purple nutsedge shoot regrowth dry weight to less than 5% of the non-treated control. Yellow nutsedge shoot regrowth dry weight from the foliar + soil and soil-only applications was less than 1% of the non-treated control.
Control of Several Perennial Weeds in Creeping Red Fescue (Festuca rubra) Grown for Seed
Authors: Darwent A. Lloyd , Lefkovitch Leonard P.
Published: March 2018

In commercial fields of creeping red fescue, spring applications of sethoxydim at 500 g/ha and fluazifop-P at 250 g/ha consistently reduced the heading, and consequently the seed production, of foxtail barley and volunteer bromegrass by ≥90% without affecting crop seed yield, 100-seed wt or germination. The effectiveness of sethoxydim at 500 g/ha and fluazifop-P at 250 g/ha to reduce heading of grass weeds was not affected by tank mixing with metsulfuron at 4.5 g/ha but was reduced when tank mixed with either dicamba plus 2,4-D at 280 plus 560 g/ha or 2,4-D alone at 560 g/ha. Metsulfuron alone, or in tank mixtures with sethoxydim (500 g/ha) or fluazifop-P (250 g/ha), effectively controlled dandelion and volunteer alsike clover (probability of ≥80% control was 0.94 or more). Dicamba plus 2,4-D provided a similar level of volunteer alsike clover control but was less effective on dandelion, while 2,4-D was ineffective on both weeds. Treatments containing dicamba plus 2,4-D reduced crop seed yield and germination, and increased seed weight.
2,4-D Interactions with Glyphosate and Sodium Bicarbonate
Authors: Thelen Kurt D. , Jackson Evelyn P. , Penner Donald
Published: March 2018

2,4-D has been reported to antagonize glyphosate activity on grass weed species. In addition, sodium bicarbonate antagonized 2,4-D activity on broadleaf species. Experiments were conducted using Nuclear Magnetic Resonance (NMR) technology to evaluate interactions of 2,4-D dimethylamine and 2,4-D butoxyethylester formulations with glyphosate in solution. The 2,4-D dimethylamine formulation associated with glyphosate to form the dimethylamine salt of glyphosate. NMR spectra also showed that the molecular orientation of the glyphosate molecule was affected by the 2,4-D butoxyethylester formulation. The antagonist was not the active 2,4-D butoxyethylester molecule itself, but appeared to be due to an association of glyphosate with organic components in the 2,4-D butoxyethylester formulation. The molecular influence of sodium bicarbonate on technical grade 2,4-D free acid, and dimethylamine and butoxyethylester formulations was also evaluated. Sodium bicarbonate was found to react with the 2,4-D free acid and 2,4-D dimethylamine to form the sodium salt of 2,4-D. The 2,4-D butoxyethylester formulation did not react with sodium bicarbonate.
Weed Control in No-till Doublecrop Soybean (Glycine max) Following Winter Wheat (Triticum aestivum) on a Clay Soil
Authors: Elmore C. Dennis , Heatherly Larry G. , Wesley Richard A.
Published: March 2018

Weed control was evaluated in no-till planted soybean in both burned and standing wheat stubble for 3 yr. High, intermediate, low, and no weed management following no-till planting of soybean were compared with a tilled treatment with high weed management. Herbicides for the high weed management were metribuzin plus metolachlor PRE followed by POST applications, as needed, of bentazon, acifluorfen, and fluazifop or quizalofop. Intermediate management included all of the above except metolachlor, plus the as-needed use of chlorimuron or lactofen POST. Low management had no PRE herbicide applications but included the above POST herbicides. Glyphosate was used as a preplant foliar applied desiccant in the stubble-planted soybean of all weed management levels. Yield of soybean was not affected by standing, burned, or tilled wheat stubble. Soil organic matter in the 0 to 2.5 cm of soil was not significantly affected at the end of the 3 yr. Yield of wheat was reduced by standing wheat stubble in the first year of the study. Total POST weed control was sufficient for maximum soybean yields in the second and third years of the study. The weed spectrum changed during the experiment for the no-weed-control treatment in soybean and in wheat. The major weeds present in soybean after 3 yr of no-till were southern crabgrass, nodding spurge, redvine, prickly sida, barnyardgrass, and johnsongrass; in wheat they were Italian ryegrass, little barley, mayweed chamomile, and hairy buttercup.
Wild Jujube (Ziziphus lotus) Control in Morocco
Authors: Regehr David L. , El Brahli Azeddine
Published: March 2018

Field studies were conducted from 1985 through 1987 to evaluate control of wild jujube, a deciduous, thorny shrub that causes complete wheat and other crop loss by preventing harvest operations. Initial herbicide or sweep tillage treatments were applied in late June or July, as plants approached maximum foliar development, to wild jujube regrowth from plants cut at ground level the previous fall. Nearly 1 yr after treatment, over 97% reduction of wild jujube regrowth was achieved with initial treatments of 7.2 and 10.7 g ae/L of the isopropylamine salt of glyphosate, 2.4 and 3.6 g ae/L of the potassium salt of picloram, and mixtures of glyphosate plus picloram at half those concentrations, followed 2 to 3 mo later with a repeat herbicide treatment or sweep tillage. About 60% reduction in wild jujube regrowth was achieved with two sweep tillage operations 25 cm deep. Mixtures of half rates of glyphosate plus picloram were less costly than full rates of glyphosate alone and had less carryover to wheat than full rates of picloram alone.
Spring Wheat (Triticum aestivum)Cultivar Responses to Trifluralin and Postemergence Herbicides
Authors: Clay Sharon A. , Gaffney Jim F. , Wrage Leon J.
Published: March 2018

Trifluralin is used for weed control in wheat but may reduce vegetative growth and yield. Postemergence (POST) herbicides may cause additional plant stress to trifluralin-stressed wheat. Field studies at Groton, SD in 1991 and 1992 and at Highmore, SD in 1992 evaluated the effects of 2,4-D-amine, difenzoquat, metsulfuron, and a combination of fenoxaprop-ethyl + 2,4-D-ester + MCPA-ester on hard red spring wheat cultivars ‘2375,’ ‘Prospect,’ and ‘Butte 86’ seeded in areas treated with preplant incorporated trifluralin either in the spring before seeding (0.56 kg ai/ha) or the previous year (1.12 or 2.24 kg ai/ha). Trifluralin applied alone in the spring, and followed by some POST herbicides, reduced shoot dry weight and grain yield. Trifluralin reduced the yield of Prospect the most and the yield of 2375 the least. Yields of trifluralin-treated wheat were reduced 23% by metsulfuron and 14% by fenoxaprop-ethyl + 2,4-D + MCPA compared to yields of wheat treated with only the respective POST herbicide. Yields were not reduced with any trifluralin-POST herbicide combination when trifluralin was applied a year prior to seeding wheat.
Potential for Biological Control of Downy Brome (Bromus tectorum)and Medusahead (Taeniatherum caput-medusae)with Crown and Root Rot Fungi
Authors: Grey William E. , Quimby Paul C. , Mathre Donald E. , Young James A.
Published: March 2018

The effects of five soil fungi, endemic to the western United States, were evaluated for disease reaction, root dry weights and shoot dry weights on five grass species. The undesired grass, downy brome or medusahead, the perennial forage species, squirreltail or western wheatgrass, and winter wheat were susceptible to take-all. Downy brome, medusahead, squirreltail, and winter wheat were susceptible to crown rot. The desired grasses, squirreltail, western wheatgrass, and winter wheat, were susceptible to barepatch. Crown rot is adapted to dry soils and may be a potential biological control on downy brome and medusahead in the arid environment of the western U.S.
Sulfonylurea Herbicide Effects on Following Crops
Authors: Moyer Jim R.
Published: March 2018

Five sulfonylurea herbicides were applied to Typic Boroll soil with pH 8.0 and 2% organic matter in the field and growth chamber to assess their residual effects on following crops. Under irrigated conditions, triasulfuron at 22 g/ha reduced the growth of alfalfa, canola, corn, lentil, pea, potato, and sugarbeet the year after application but caused no injury after two years. Alfalfa GR50(rate required to reduce growth by 50%) values immediately after application of chlorsulfuron, triasulfuron, and metsulfuron were < 2.2 g/ha and similar in the growth chamber and field. Alfalfa and canola GR50values immediately after thifensulfuron application in the growth chamber were ≥ 90 g/ha. Alfalfa, canola, flax, and sugarbeet GR50for tribenuron in the growth chamber were < 4 g/ha. Crop response curves developed by growth chamber experiments could replace many of the multiple site and crop field experiments now required to develop recropping guidelines for residual herbicides.
Broadleaf Weed Control with Trifluralin Plus Flumetsulam in Soybean (Glycine max)
Authors: Reynolds Daniel B. , Jordan David L. , Vidrine P. Roy , Griffin James L.
Published: March 2018

In 12 trials in Louisiana, sicklepod, entireleaf morningglory, pitted morningglory, and hemp sesbania control 4 wk after planting was greater with trifluralin applied PPI followed by chlorimuron plus metribuzin applied PRE than with trifluralin plus flumetsulam applied PPI. Sicklepod control with these herbicides was similar 6 wk after application. No differences in soybean yield were noted. Chlorimuron applied POST following trifluralin applied PPI and metribuzin applied PRE or trifluralin plus flumetsulam applied PPI improved weed control and soybean yield compared with soil-applied herbicides alone. Excellent barnyardgrass control was obtained with all herbicide programs.
Canola (Brassica napus) Response to Simulated Sprayer Contamination with Thifensulfuron and Thifensulfuron:Tribenuron (2:1)
Authors: Wall David A. , Derksen Douglas A. , Friesen Lyle F.
Published: March 2018

Greenhouse and field studies were conducted in 1992 and 1993 in Manitoba and Saskatchewan to determine the effect of simulated sprayer contamination with thifensulfuron and thifensulfuron:tribenuron (2:1) on canola. In greenhouse studies, canola was more sensitive to tribenuron and thifensulfuron:tribenuron (2:1) than thifensulfuron. Thifensulfuron was more phytotoxic to canola when applied with Merge (50% surfactant blend and 50% petroleum hydrocarbon solvents) than with Agral 90 (non-ionic spreader and activator) at recommended adjuvant concentrations {1% and 0.2% (v/v), respectively}. In the field, canola injury tended to be more severe when thifensulfuron was applied with Merge than with Agral 90, but yields did not differ significantly between adjuvants, Thifensulfuron and thifensulfuron:tribenuron (2:1) at rates as low as 0.1 g ai/ha severely injured canola, delayed flowering, and reduced yield and subsequent seed germination. Thifensulfuron at 0.1 to 0.15 g/ha in mixtures with sethoxydim plus Merge reduced yields up to 61%.
Sugarbeet (Beta vulgaris) Response to and Sorption Characteristics of Nicosulfuron and Primisulfuron
Authors: Novosel Karen M. , Renner Karen A. , Kells James J. , Chomas Andrew J.
Published: March 2018

Nicosulfuron and primisulfuron are sulfonylurea herbicides that may persist in the soil and injure sensitive rotational crops such as sugarbeet. Studies were initiated to measure sugarbeet response one and two years after application of 70 and 140 g/ha of nicosulfuron and 40 and 80 g/ha of primisulfuron to corn. Nicosulfuron did not injure sugarbeet one or two years after application. In contrast, sugarbeet yield was reduced one year after application of 40 and 80 g/ha of primisulfuron. Injury was visible two years after application of 80 g/ha primisulfuron but this did not cause a yield reduction. In greenhouse studies, the concentration of nicosulfuron and primisulfuron that reduced sugarbeet growth by 50% were determined for six soils. Primisulfuron reduced sugarbeet growth more than nicosulfuron on four of six soils indicating greater potential for sugarbeet injury from primisulfuron. Sugarbeet response was highly correlated with soil organic matter content (R2= 0.88). The sorption coefficients, Kdvalues, for nicosulfuron were 0.30 to 2.58 and the Kdvalues for primisulfuron were 0.76 to 3.47. Primisulfuron Kdvalues were higher than those of nicosulfuron on four of five soils indicating stronger affinity of primisulfuron for soil sorptive sites. The Kdvalues for both herbicides indicate low overall sorption. The greater sugarbeet injury observed in the field from primisulfuron is not due to greater availability of primisulfuron compared to nicosulfuron.
Expert System Evaluation and Implementation for Soybean (Glycine max) Weed Management
Authors: Monks C. Dale , Bridges David C. , Woodruff John W. , Murphy Tim R. , Berry Daniel J.
Published: March 2018

HERB, a computer-based expert system for soybean weed management developed at North Carolina State University, was evaluated for managing weeds under Georgia conditions. The project was initiated in two phases: a) training Cooperative Extension county agents followed by evaluation in six Georgia counties and b) revision, licensing, and distribution across the state. Field evaluations indicated that HERB was not highly accurate for predicting final yield loss because of weed species senescence and environmental extremes later in the growing season. HERB generally provided a reasonable prediction for a positive economic return due to treatment approximately 60% of the time. Accuracy was directly dependent upon the accuracy of weed-free yield estimates and extremes in growing conditions. HERB should not be the sole source of weed management information but may be useful to producers and county agents where mixed or low populations of weeds exist. The program was distributed statewide in 1993 after revision, duplication, and training was completed.
Response of Sulfonylurea-Tolerant Soybean (Glycine max) and Selected Weed Species to Imazethapyr and Thifensulfuron Combinations
Authors: Simpson D. M. , Stoller E. W.
Published: March 2018

Sulfonylurea-tolerant soybean (STS soybean) tolerance to imazethapyr (70 g/ha) plus thifensulfuron (4.4 g/ha) tank mixture was evaluated in 1993 and 1994 at two locations in Illinois. Thifensulfuron injury was reduced from 27% in non-STS soybean to 1% in STS soybean 14 days after treatment (DAT). STS and non-STS soybean did not differ in response to imazethapyr alone with < 6% injury 14 DAT. Injury from the tank mix was reduced from 40% in non-STS soybean to 24% in STS soybean 14 DAT. However, a synergistic interaction between the herbicides exists in STS soybean. The yield of injured soybean was not reduced in either STS or non-STS soybean. Injury to STS soybean from the tank mix was decreased by reducing the rate of imazethapyr from 70 g/ha to 52.5 or 35 g/ha. Reducing the thifensulfuron rate mixed with imazethapyr at 70 g/ha did not decrease injury in STS soybean. Control of smooth pigweed, common lambsquarters, and common cocklebur was not affected by reducing the rate of either herbicide in the tank mixture.
Common Lambsquarters (Chenopodium album) Control in Corn (Zea mays) with Postemergence Herbicides and Cultivation
Authors: Parks Robert J. , Curran William S. , Roth Gregory W. , Hartwig Nathan L. , Calvin Dennis D.
Published: March 2018

Greenhouse studies assessed the susceptibility of three common lambsquarters biotypes to foliar-applied bromoxynil, dicamba, and thifensulfuron. Field studies evaluated the effectiveness of the same herbicides in conjunction with atrazine and row cultivation for the control of common lambsquarters in corn. In the field, bromoxynil was applied at 140, 280, and 420 g/ha, dicamba at 140, 280, and 560 g/ha, and thifensulfuron at 2, 3, and 4 g/ha. In the greenhouse, bromoxynil and thifensulfuron reduced common lambsquarters growth by at least 55%, while dicamba reduced growth 45% or less. Two of the three biotypes were resistant to atrazine. In the field, weed control was up to 70% better in cultivated plots than in noncultivated plots. Cultivation sometimes promoted additional weed emergence, but later emerging weeds rarely reached reproductive maturity. Atrazine improved the level of weed control only if triazine-susceptible weeds were present. The lowest rates of bromoxynil and dicamba (140 g/ha) controlled common lambsquarters 85% or greater even without cultivation, whereas control with the low rate of thifensulfuron (2 g/ha) was acceptable (greater than 85%) 8 wk after planting only in combination with cultivation. Combinations of reduced herbicide rates and mechanical cultivation provided effective, alternative control strategies for both triazine-resistant and susceptible common lambsquarters.
Effects of Prodiamine on Tall Fescue (Festuca arundinacea) Rooting
Authors: Han Sangwook , Fermanian Thomas W. , Voigt Thomas B.
Published: March 2018

With the increased development of new tall fescue cultivars used in turf, it is important to understand their individual response to herbicide treatment. The effect of prodiamine on tall fescue root dry weight and root length of selected tall fescue cultivars was studied in the greenhouse in 1.3-m-deep pots of calcined clay. Prodiamine at 0.8 kg ai/ha did not significantly affect either root dry weight or root length. However, the mean root dry weight and maximum root length averaged over all cultivars were significantly reduced at 4 wk after treatment with 1.7 kg/ha. When the prodiamine treatments were repeated in a second experiment, both rates caused a significant reduction in the mean root dry weight and maximum root length but there was no significant difference between prodiamine rates. Single degree of freedom contrasts between the untreated and treated turfs for each cultivar had some differential response in root dry weight. The reduction in root dry weight in the prodiamine treatments was more pronounced in the second study because the turf was less mature. ‘Olympic’ and ‘Rebel’ tall fescue had significantly reduced root dry weight at the 1.7 kg/ha rate in first study; whereas, ‘Amigo,’ Olympic, ‘Sundance,’ and ‘Taurus' tall fescue had significant reduction in root dry weight at both 0.8 and 1.7 kg/ha prodiamine rates. ‘Midnight’ Kentucky bluegrass had significantly reduced root length at both prodiamine rates in the second experiment but in general there was little difference among tall fescue cultivars treated with prodiamine.
Preemergent Control of Long-Stalked Phyllanthus (Phyllanthus tenellus) and Leafflower (Phyllanthus urinaria)
Authors: Norcini Jeffrey G. , Stamps Robert H. , Aldrich James H.
Published: March 2018

The efficacy of two applications of several PRE herbicides for extended control of long-stalked phyllanthus and leafflower were evaluated under container nursery conditions at two climatically different sites in Florida. Prodiamine at 4.5 kg ai/ha provided the longest and most consistent reductions in number, percent coverage (visual) of the medium, and dry weight of both species. Ten weeks of excellent PRE control (percent medium coverage ≤ 10%; number of weeds reduced by ≥ 70%) of both species was obtained at one site after the first and second applications of prodiamine at 2.2 or 4.5 kg ai/ha; two applications were required at the second site for similar control. Rates of the other herbicides were generally too low for excellent control of both species after one application, the exceptions being dithiopyr at 4.5 kg ai/ha and the preformulated combination of isoxaben and oryzalin (1.1 and 3.4 kg ai/ha, respectively). These herbicides provided good (10% < percent medium coverage ≤ 20%; number of weeds reduced by ≥ 70%) to excellent PRE control of long-stalked phyllanthus after the first and second applications at one site. Percent coverage of the medium by either species in untreated containers was 96 to 100%.
Influence of Fenoxaprop and Ethofumesate Treatments on Suppression of Common Bermudagrass (Cynodon dactylon) in Tall Fescue (Festuca arundinacea) Turf
Authors: Johnson B. Jack , Carrow Robert N.
Published: March 2018

Experiments were conducted over a 3-yr period to determine the rate and frequency of herbicide application needed to control common bermudagrass growing in a tall fescue turf. In Experiment I, fenoxaprop plus ethofumesate applied at 0.2 + 1.7 kg/ha in late April and repeated at the same rate at 3- to 4-wk intervals for a total of five applications resulted in excellent (≥ 97%) common bermudagrass suppression. The suppression was higher from combination of fenoxaprop and ethofumesate than when fenoxaprop was applied at 0.2 kg/ha in five applications (≤ 67%). In Experiment II, fenoxaprop plus ethofumesate applied at 0.2 +1.7 kg/ha required four applications per year to effectively suppress common bermudagrass (95%) in 1993, but five applications were needed to obtain similar suppression (96%) in 1994. Tifway bermudagrass was not suppressed during 1994 when fenoxaprop plus ethofumesate were applied at 0.2 +1.7 kg/ha in each of five applications (30%). In most instances, fenoxaprop plus ethofumesate applied at 0.2 +1.7 kg/ha caused only slight to moderate (< 30%) injury to tall fescue for 1 to 2 wk after treatment. When injury occurred, it was temporary as the turf fully recovered within 2 to 3 wk after treatment. An exception occurred in early July 1992 when fenoxaprop plus ethofumesate caused 44% injury to tall fescue after the four applications.
Imazapyr Applied Postemergence in Sunflower (Helianthus annuus) for Broomrape (Orobanche cernua) Control
Authors: Garcia-Torres Luis , Castejon-Muñoz Mercedes , Lopez-Granados Francisca , Jurado-Exposito Montserrat
Published: March 2018

Field studies were conducted from 1991 through 1994 in several locations of Southern Spain to determine the efficacy of imazapyr as late postemergence application in sunflower for broomrape control and the crop response to this herbicide under weed-free conditions. Single applications of imazapyr at 10 to 15 g/ha on sunflower plants at about theV12(12 leaves) toV19(19 leaves) growth stages, infected with broomrape plants at the predominant growth stages “c” (small nodule with shoot bud visible) and “d” (shoot bud and roots well developed), resulted in effective control without damaging the crop. Double applications of imazapyr at 10 + 10 g/ha at about the same crop growth stages V12 to V19, at a time interval of 12 to 14 d between single applications, were also efficacious and well tolerated by the crop. The same herbicide treatments applied to weed-free sunflower did not adversely affect the biomass, head diameter or yield of the crop as compared with the nontreated check. As a result of the low rate of imazapyr required for broomrape control, the herbicide treatments are economical (about $3 to $6/ha), non-residual and not affected by the type of soil texture and rainfall conditions.
Effect of Weed Management Strategy and Planting Date on Herbicide Use in Peanuts (Arachis hypogaea)
Authors: Linker H. Michael , Coble Harold D.
Published: March 2018

Experiments were conducted in 1987 and 1988 at two locations each year to determine how two weed management strategies and three planting dates affected the cost and amount of herbicide needed to control weeds in peanuts. Weed management strategies used for each planting date included preventive, which duplicated a standard grower program, or an integrated weed management system. The least expensive strategy depended upon weed species composition, weed populations and planting date. In all cases, the integrated weed management strategy required less herbicide (acid equivalent or active ingredient) than the preventive strategy.
Effect of Simulated Rainfall on Herbicide Performance in Huisache (Acacia farnesiana) and Honey Mesquite (Prosopis glandulosa)
Authors: Bovey Rodney W. , Meyer Robert E. , Whisenant Steven G.
Published: March 2018

Greenhouse and field experiments were conducted in east-central Texas to evaluate the influence of simulated rainfall on the availability of foliar-applied herbicides for huisache and honey mesquite control. The foliar activity of the amine salts of glyphosate, dicamba, picloram, clopyralid, and triclopyr was decreased on greenhouse-grown huisache when simulated rainfall was applied up to 240 min after herbicide treatment. The effectiveness of the butoxyethyl ester of triclopyr or 2,4,5-T was not reduced by rainfall washoff within 15 min after application. In natural huisache stands, injury from the ester of triclopyr or amine salts of picloram or clopyralid was not reduced by simulated rainfall at 60 min after herbicide treatment. In the greenhouse and field, honey mesquite leaves rapidly absorbed most herbicides, and triclopyr, 2,4,5-T, picloram, and clopyralid were highly phytotoxic even when simulated rainfall was applied within 15 min after herbicide treatment.
Effect of Oxyfluorfen, Pyridate, and BAS 514 Applied Postemergence on Direct-seeded Broccoli (Brassica oleraceavar.botrytis)
Authors: Herbst Kathleen A. , Derr Jeffrey F.
Published: March 2018

Broccoli treated with 0.07 kg ai/ha oxyfluorfen, 0.28 and 0.56 kg ai/ha pyridate, and 0.14 kg ai/ha BAS 514 at four field locations produced yields similar to the cultivated check. Oxyfluorfen at 0.14 and 0.28 kg/ha, pyridate at 1.0 and 2.0 kg/ha, and BAS 514 at 0.28 and 0.56 kg/ha reduced broccoli yield at one or more locations. Broccoli treated with BAS 514 plus the experimental adjuvant BAS 090 had increased injury and decreased yield when compared to BAS 514 applied alone. Little to no stand reduction was observed with any herbicide treatment. Direct-seeded broccoli is marginally tolerant to rates of oxyfluorfen, pyridate, and BAS 514 that control broadleaf weeds acceptably.
Influence of Temperature, Rainfall, Grass Species, and Growth Stage on Efficacy of Fluazifop
Authors: Smeda Reid J. , Putnam Alan R.
Published: March 2018

Field experiments were initiated to determine the efficacy of fluazifop as influenced by growth stage for green, yellow, and giant foxtail, large crabgrass, and Japanese millet. Additionally, the influence of air temperature and simulated rainfall on fluazifop efficacy for green foxtail and Japanese millet was determined by greenhouse and growth-room experiments. In both 1983 and 1984, fluazifop activity was reduced as the growth stage increased from 3- to 5- to 7-leaf for all species. Significant differences among species in susceptibility to fluazifop were evident with the descending order of tolerance: green foxtail > large crabgrass > yellow foxtail > giant foxtail > Japanese millet. Increasing the air temperature from 18 to 30 C reduced fluazifop control of green foxtail at herbicide rates less than 0.14 kg ai/ha but did not affect Japanese millet. A 1- to 2-h rain-free interval was required for optimum control of green foxtail and Japanese millet at 0.07 kg/ha fluazifop; the interval was reduced to 45 and 15 min, respectively, when fluazifop rates were 0.14 kg/ha. The longer rain-free interval required for optimum control of green foxtail compared to Japanese millet may reflect a slower rate of herbicide absorption in green foxtail.
Direct-Seeded Broccoli (Brassica oleraceavar.botrytis) Response to Oxyfluorfen and BAS 514 Applied Preemergence
Authors: Herbst Kathleen A. , Derr Jeffrey F.
Published: March 2018

Oxyfluorfen applied preemergence at 0.14, 0.28, and 0.56 kg ai/ha reduced stand of direct-seeded broccoli 40 to 99%, while BAS 514 applied at the same rates did not reduce stand. Broccoli plants that survived oxyfluorfen exhibited 32 to 97% injury 6 to 9 weeks after treatment. BAS 514 at 0.14, 0.28, and 0.56 kg ai/ha caused 6 to 35% crop injury. Oxyfluorfen at 0.28 and 0.56 kg/ha reduced yield compared to the cultivated check at all locations. At one location, all rates of BAS 514 reduced broccoli yield compared to the cultivated check. The two low rates of oxyfluorfen and the two high rates of BAS 514 delayed crop maturity approximately 1 week at one location.
Spotgun-Applied Hexazinone: Release of Red Pine (Pinus resinosa) from Quaking Aspen (Populus tremuloides) Competition and Residue Persistence in Soil
Authors: Prasad Raj , Feng Joseph C.
Published: March 2018

Weed control and red pine release by spotgun-applied hexazinone in a northern Ontario plantation were evaluated 3 yr after treatment, while hexazinone residues and lateral movement in the sandy loam soil were determined 1 yr after treatment. Hexazinone, grid pattern spot applied at 480 mg ai/spot, approximating 1.6 kg ai/ha, resulted in 88% quaking aspen stem dieback and variable suppression of white birch and pin cherry. The height and basal diam of treated red pine were 131 and 150% of control, respectively, after 3 yr. Hexazinone residues were reduced to 1% at the treated spot and did not move laterally beyond 0.5 m, 1 yr after treatment. Detection of small amounts of metabolites A and B (0.2 and 0.3%) indicated the non-cumulative degradation of hexazinone in soils.
Weeds – A System for Developing a Computer-Based Herbicide Recommendation Program
Authors: Linker H. M. , York A. C. , Wilhite D. R.
Published: March 2018

A rapid increase in the number of herbicides and herbicide mixtures registered for use in row crops has made herbicide selection difficult. WEEDS is a computer program that enables a weed management expert to build a list of recommended herbicides or herbicide mixtures based upon weed species, soil texture, and soil organic matter content. An example is given for soybeans.
Preemergence Activity of Dinitroaniline herbicides Used for Weed Control in Cool-Season Turfgrasses
Authors: Bhowmik Prasanta C. , Bingham S. Wayne
Published: March 2018

Dinitroaniline herbicides are major herbicides used to control annual grass weeds in cool-season turfgrasses. At least three herbicides, benefin, pendimethalin, and trifluralin are labeled preemergence to control weeds in established turfgrass. Prodiamine could be a competitive product. Benefin at 2.2 to 3.4 kg ai/ha, pendimethalin at 1.7 to 3.4 kg ai/ha, prodiamine at 0.6 to 1.7 kg ai/ ha, and benefin plus trifluralin at 1.1 plus 0.6 to 2.3 plus 1.1 kg ai/ha effectively control many annual grass weeds, including large and smooth crabgrass, yellow and green foxtail, barnyardgrass, goosegrass, fall panicum, and annual bluegrass. Most dinitroaniline herbicides provide residual preemergence weed control for the entire growing season. In general, Kentucky bluegrass, perennial ryegrass, tall fescue, red fescue, and other cool-season turfgrasses tolerate most of these herbicides, although higher-than-normal rates of any dinitroaniline herbicide could restrict root growth and cause stand thinning in turfgrass species.
Wild-Proso Millet (Panicum miliaceum) Control in Central Great Plains Irrigated Corn (Zea mays)
Authors: Westra Philip , Wilson Robert G. , Zimdahl Robert L.
Published: March 2018

Wild-proso millet control in furrow-irrigated corn was evaluated in Colorado and Nebraska in 1986 and 1987. No single herbicide alone controlled wild-proso millet all season. In Colorado, EPTC applied preplant incorporated followed by cyanazine plus pendimethalin applied early postemergence controlled 94% of wild-proso millet. Acetochlor applied preemergence followed by cyanazine plus pendimethalin applied early postemergence controlled wild-proso millet better all season (93%) than alachlor (81%) or metolachlor (71%) followed by the same early postemergence strategy. Successful Colorado wild-proso millet management treatments (>85% season-long control) increased corn yields an average of 3260 kg ha-1compared to the untreated control. To obtain wild-proso millet control of 90% or more in Nebraska in 1986, alachlor, cycloate, EPTC, and metolachlor applied had to be combined with cyanazine plus pendimethalin applied early postemergence. Average corn yields in herbicide-treated areas in Nebraska were 2980 kg ha-1higher than those recorded in the untreated control.
Wild-Proso Millet (Panicum miliaceum) Control in Soybeans (Glycine max) With Postemergence Herbicides
Authors: Harvey R. Gordon , Porter Donald J.
Published: March 2018

Selective postemergence herbicides were applied broadcast to control wild-proso millet in soybeans early postemergence (early post), postemergence (post), and late postemergence (late post) when wild-proso millet was 2 to 8 cm tall, 3 to 15 cm tall, and 3 to 31 cm tall, respectively. CGA-82725, fluazifop, haloxyfop, and sethoxydim applied early post controlled 75% or less late-season wild-proso millet. Interrow cultivation following early post fluazifop applications improved wild-proso millet control and soybean yields. Higher rates of CGA-82725, haloxyfop, and sethoxydim applied post controlled 91 to 98% late-season millet, but resulting soybean yields were less than the hand-weeded check. Fenoxaprop, fluazifop, fluazifop-P, haloxyfop, quizalofop, and sethoxydim applied late post provided 93 to 99% late-season millet control and soybean yields equal to hand-weeded checks. Wild-proso millet emerging after early post or post herbicide applications contributed to reduced effectiveness from those treatments. However, most wild-proso millet emerged before late post applications and were controlled. Other herbicides including BAS-51702, clethodim, cloproxydim, and SC-1084 applied late post also controlled wild-proso millet in soybeans.
Control of Wild-Proso Millet (Panicum miliaceum) with Imazethapyr
Authors: Swanton Clarence J. , Chandler Kevin
Published: March 2018

Several weedy biotypes of wild-proso millet occur throughout Ontario. Field and laboratory studies were conducted in 1986 and 1987 to evaluate imazethapyr for preemergence and postemergence control of wild-proso millet. In the laboratory, imazethapyr, applied postemergence, effectively controlled weedy biotypes of wild-proso millet in the 4- to 5-leaf stage. Seedlings of black-seeded wild-proso millet were controlled at the 1- to 5-leaf stage by 50 g ai/ha of imazethapyr. Higher doses of imazethapyr were required to control later growth stages. In field studies, imazethapyr, applied preemergence or postemergence, effectively controlled black-seeded wild-proso millet, resulting in soybean yields comparable to the recommended postemergence treatment of sethoxydim.
Response of Bermudagrass (Cynodon spp.) Cultivars to Multiple Plant Growth Regulator Treatments
Authors: Johnson Belly J.
Published: March 2018

Plant growth regulators were evaluated on common and African ‘Tifway’ bermudagrass. Flurprimidol plus mefluidide applied at 1.1 plus 0.14 kg ha-1 and followed by 0.56 plus 0.14 kg ha-1 at 2- to 3-week interval suppressed vegetative growth of mowed common bermudagrass for 5 wk (17 to 23%) and unmowed turf for 6 wk (40%), but severely injured the turf. The injury ranged from 25 to 32% from 2 to 6 wk after treatment. The plant growth regulators that injured common bermudagrass less than flurprimidol plus mefluidide did not suppress the mowed turf for as long a period. Vegetative growth of common bermudagrass not mowed was suppressed for 6 wk when treated once with flurprimidol plus mefluidide and twice with flurprimidol, mefluidide, imazethapyr, paclobutrazol (1.1 plus 1.1 kg ha-1), and paclobutrazol plus mefluidide. Of the plant growth regulators evaluated, only imazethapyr suppressed common bermudagrass seedheads. The suppression was 70% for 4 wk, but reduced to <70% by 5 wk. Paclobutrazol applied initially at 1.1 kg ha-1 and followed at 0.56 kg ha-1 suppressed vegetative growth of mowed Tifway bermudagrass for 5 wk and unmowed turf for 8 wk without causing severe injury. The suppression of mowed Tifway bermudagrass with two applications of paclobutrazol was as good or better than with any other plant growth regulator. All plant growth regulators suppressed vegetative growth of unmowed Tifway bermudagrass for 8 wk.
Johnsongrass Control with DPX-V9360 and CGA-136872 in Corn (Zea mays) in Virginia
Authors: Foy Chester L. , Witt Harold L.
Published: March 2018

Five field experiments were conducted at two locations in Virginia during 1988–89 to evaluate DPX-V9360 and CGA-136872 for postemergence control of johnsongrass in field corn grown under no-till and conventional conditions. DPX-V9360 at rates of 35 (except in no-till plots), 52, and 69 g ai ha-1applied to 8-leaf johnsongrass was 88 to 98% effective in 1988. CGA-136872 at 25, 49, and 99 g ha-1was 80% effective at the highest rate. Applications of these herbicides to 6-leaf johnsongrass resulted in 69% or less control. DPX-V9360 at 35, 52, and 69 g ha-1and CGA-136872 at 20 and 40 g ha-1applied to johnsongrass up to 48 cm in height provided 77 to 97% control at 7 WAT3in an excellent stand of conventionally planted corn during 1989. Crop yields were more than doubled with herbicide treatments relative to yields in control plots. At a second location where crop damage caused by other factors resulted in a weak stand, DPX-V9360 provided 61 to 96% control compared to 29 to 56% control with CGA-136872.
Differential Effects of UAN on Antagonism with Bentazon
Authors: Gerwick B. Clifford , Tanguay Lisa D. , Burroughs Frank G.
Published: March 2018

The effect of urea ammonium nitrate (UAN) on the antagonism of sethoxydim, haloxyfop, or the methyl ester of haloxyfop activity by bentazon was evaluated in greenhouse and field trials on yellow and giant foxtail. Including UAN in the spray solution in the absence of bentazon did not enhance the activity of any of the three grass herbicides. However, adding UAN to sethoxydim or haloxyfop in the presence of bentazon decreased the bentazon antagonism of grass activity. Conversely, UAN increased bentazon antagonism of the activity of haloxyfop methyl ester. The differential effect of UAN was not linked to effects on spray solution pH.
Effects of Glyphosate and Surfactant Concentrations on Giant Burreed (Sparganium eurycarpum) Control with a Ropewick Applicator
Authors: Leif John W. , Oelke Ervin A.
Published: March 2018

Field and laboratory experiments were conducted to evaluate the effect of glyphosate concentration, surfactant concentration, and ammonium sulfate on the control of giant burreed when applied through a ropewick applicator. Under non-flooded conditions, a 30% (v/v) solution of glyphosate applied with a ropewick applicator gave the highest giant burreed injury in 1987 and 1988, and reduced corm and rhizome viability compared to the nontreated control in 1987. Warm, dry conditions may have been responsible for poor long-term control in 1988 by reducing translocation of glyphosate to rhizomes. Addition of ammonium sulfate or surfactant did not influence glyphosate toxicity to giant burreed when applied with a ropewick applicator. In the laboratory, leaf necrosis at the point of application was observed with surfactant at 0.6% or 1.2% regardless of glyphosate concentration. Absorption of14C-glyphosate increased two-fold with the addition of surfactant, and translocation to roots and rhizomes decreased almost two-fold as surfactant concentration was increased from 0 to 1.2%. Electrolyte leakage increased with 30% glyphosate when surfactant concentration was increased from 0 to 1.2%. Localized leaf necrosis and disruption of tissues inside the leaf may be responsible for reduced giant burreed control with glyphosate and surfactant applied in high concentrations.
Wheat (Triticum aestivum) Tolerance to Triallate Applied Spring Preplant-Incorporated
Authors: McMullan Patrick M. , Nalewaja John D.
Published: March 2018

Research was conducted to determine environmental and cultural factors influencing triallate phytotoxicity to hard red spring wheat. Triallate injured ‘Alex’ wheat more than ‘Coteau’ but injury was not influenced by triallate application date. Wild oat control was greater when triallate was applied immediately before seeding compared to 12 d before seeding. Triallate tolerance in wheat did not relate to solid stem characteristic. Injury was highest when wheat was seeded in a 4-cm incorporated triallate layer and least when wheat was seeded below the treated layer. However, triallate injury to wheat was similar at both seeding depths within the 8-cm incorporated triallate layer. Triallate at 1.1 kg ai ha-1reduced wheat fresh weight approximately 33% with a soil at 8 C but over 84% with a soil at 24 C.