bluuebunny/crossref_metadata_2025 huggingface dataset:
Common Lambsquarters
Authors: Mitich Larry W.
Published: March 2018

Common lambsquarters or fat hen (Chenopodium album L. # CHEAL) was classified by Linneaus in 1753. The generic name is from the Greek chen, a goose, and pous or podos, a foot; the leaf shape of plants in this genus are reminiscent of goose feet. The goosefoot family, Chenopodiaceae, includes many vegetables: table beets, sugar beets, spinach, and mangold. The name ‘fat hen’, used for several plants of the Goosefoot family, was first published in English in 1795.
Response of Bermudagrass (Cynodonspp.) to Plant Growth Regulators
Authors: Johnson Billy J.
Published: March 2018

Plant growth regulators were evaluated on African ‘Tifway’ and common bermudagrass. The vegetative growth of mowed Tifway bermudagrass was suppressed 15 to 22% for 3 weeks by flurprimidol at 0.84 kg ai/ha while mowed common bermudagrass was suppressed 30 to 34% during the same period by flurprimidol at 1.1 kg/ha. When nonmowed bermudagrass was treated with flurprimidol, the growth of Tifway treated at 0.84 kg/ha was suppressed 42% at 8 weeks while growth of common bermudagrass treated at 1.1 kg/ha was suppressed 26% at 6 weeks. Excessive injury by flurprimidol occurred when common and Tifway bermudagrass were treated at rates above 1.1 and 0.84 kg/ha, respectively. Imazethapyr excessively injured both bermudagrass cultivars. Mefluidide and Mon 4620 injured both bermudagrass cultivars slightly, but neither suppressed vegetative growth as effectively as flurprimidol.
Weed Control in Winter Wheat (Triticum aestivum) with Chlorsulfuron and CGA 131036 and Comparison of Modes of Action
Authors: Klingaman Tracy E. , Peeper Thomas F.
Published: March 2018

In field experiments, chlorsulfuron and CGA 131036 did not injure winter wheat. Both herbicides applied postemergence at 9 and 10 g ai/ha completely controlled flixweed. CGA 131036 controlled cutleaf eveningprimrose 81%, and chlorsulfuron controlled 91%. At similar rates, CGA 131036 was also less effective than chlorsulfuron on henbit and Italian ryegrass. Both controlled wild buckwheat 77% when applied postemergence at 18 g/ha. Neither of the sulfonylurea herbicides controlled prostrate spurge or woolly croton as effectively as 2,4-D. In a bean root bioassay, root growth inhibition by both herbicides was partially alleviated by adding isoleucine and valine.
Sulfometuron for Eliminating Bahiagrass (Paspalum notatum) From Centipedegrass (Eremochloa ophiuroides) and Bermudagrass (Cynodon dactylon)
Authors: Hanna Wayne W. , Swann Charles W. , Schroeder Jill , Utley Phil R.
Published: March 2018

This study was conducted to determine if ‘Pensacola’ bahiagrass, a major weed in turf and pastures in the southeastern United States, could be eliminated selectively from centipedegrass and ‘Tifway’ bermudagrass turf and a ‘Coastal’ bermudagrass pasture by treating with sulfometuron. Established Pensacola bahiagrass usually was controlled satisfactorily in Tifway bermudagrass and centipedegrass turf and in a Coastal bermudagrass pasture with sulfometuron at 210, 160, 105 g ai/ha applied twice, respectively. Bahiagrass seedlings were eliminated from both newly planted centipedegrass and Tifway bermudagrass turf with 105 g/ha sulfometuron applied once.
New Herbicides for Weed Control in Established Alfalfa (Medicago sativa)
Authors: Wilson Robert G.
Published: March 2018

Spring-applied herbicides were evaluated in field studies conducted in 1985 through 1987 in western Nebraska for selective weed control in irrigated established alfalfa. Imazethapyr, norflurazon, pendimethalin, and prodiamine did not injure alfalfa but varied in their weed control spectrums. Overall weed densities were lowest in plots treated with norflurazon at 2.8 kg ai/ha and diuron at 1.8 kg/ha.
Established Forage Alfalfa (Medicago sativa) Tolerates Glyphosate and SC-0224 Applied to Control Dodder (Cuscutaspp.)
Authors: Dawson Jean H.
Published: March 2018

Established alfalfa treated with glyphosate at 75 or 150 g ae/ha (rates known to control dodder) during the vegetative or bud stage showed symptoms of narrowed leaves and mildly chlorotic new growth, and yield of one cutting of alfalfa usually was reduced by 10 to 20%. Glyphosate, applied in the vegetative stage, affected the treated foliage more than postharvest regrowth. Applied at bud stage, the regrowth that followed harvest of treated foliage was affected more. Symptoms and effect on yield were greater at 300 g ae/ha, but alfalfa always recovered. Applying glyphosate at 75 or 150 g ae/ha in each of two or three sequential cuttings showed no cumulative effect. Glyphosate and SC-0224 had similar effects on alfalfa and suppressed alfalfa much less than would a severe infestation of dodder.
Soil-Applied Herbicide and Soil-Temperature Effects in Pinto Bean (Phaseolus vulgaris)
Authors: Nkwen-Tamo Ernest , Jeffery L. S. , Robison Laren R. , Jolley Von D.
Published: March 2018

Effects and interactions of two soil temperatures, 19 ± 1 and 27 ± 3 C, and seven soil-applied herbicide treatments on the morphological development and concentrations of eight essential nutrients in leaves, stems, and roots of pinto beans were determined. Soil temperature did not affect overall plant morphology but did affect some nutrient concentrations in the roots, stems, and leaves. Combinations of alachlor plus trifluralin at 2.2 plus 0.28 kg ai/ha and EPTC plus trifluralin at 2.2 plus 0.28 kg ai/ha caused greater negative effects than when the herbicides were applied separately. Oryzalin at 0.56 kg ai/ha and EPTC at 3.4 kg ai/ha induced the least number of morphological effects, while alachlor at 3.4 kg ai/ha, chloramben at 2.2 kg ai/ha, and trifluralin applied at 0.56 kg ai/ha produced an intermediate number. Alachlor, trifluralin, and combinations of alachlor plus trifluralin and EPTC plus trifluralin inhibited nodule growth. Each herbicide affected different nutrients. Alachlor plus trifluralin affected the level of each nutrient in at least one plant tissue. Many herbicide-soil temperature interactions occurred.
Differential Tolerance of Woody Nursery Crop Seedlings to Napropamide
Authors: Sumaryono  , Crabtree Garvin
Published: March 2018

Experiments are conducted to evaluate the tolerance of three deciduous species: black locust, honeylocust, apple, and three coniferous species: Douglas fir, ponderosa pine, and Japanese black pine, in the seedling stage to napropamide. Deciduous species were more susceptible to napropamide than coniferous species. Domestic apple had the slowest seed germination and root development and was more susceptible. The deciduous species had more secondary roots in the shallow soil layer which contained most of the herbicide than the coniferous species. The roots of all woody species tested in vitro were inhibited significantly by contact with the herbicide, but only shoot growth of domestic apple and black locust was inhibited. Injury to woody nursery crop seedlings may be avoided by delaying herbicide application.
Tomato (Lycopersicon esculentum) Tolerance to Diphenyl Ether Herbicides Applied Postemergence
Authors: Masiunas John B.
Published: March 2018

Tolerance of tomato cultivars to diphenyl ether herbicides applied postemergence was determined in greenhouse and field experiments. In greenhouse experiments, tomato cultivar tolerance differed, but acifluorfen injured all genotypes. ‘Carmen’, ‘PetoPride 2’ and ‘Heinz 1350’ tolerated acifluorfen while ‘Advantage’, and ‘Red Plum’ were susceptible. Growth habit and tolerance to 1.1 kg ae/ha acifluorfen was significantly correlated (r2= 0.24). Field-planted tomato cultivars' tolerance to diphenyl ether herbicides applied postemergence differed. Heinz 1350 and ‘Veeroma’ tolerated diphenyl ethers, while Advantage and Red Plum were susceptible. Potency of diphenyl ethers also varied with oxyfluorfen the most injurious and acifluorfen and fomesafen the least injurious.
Preplant Weed Control in a Ridge-Till Soybean (Glycine max) and Grain Sorghum (Sorghum bicolor) Rotation
Authors: Regehr David L. , Janssen Keith A.
Published: March 2018

Research in Kansas from 1983 to 1986 evaluated early preplant (30 to 45 days) and late preplant (10 to 14 days) herbicide treatments for weed control before ridge-till planting in a soybean and sorghum rotation. Control of fall panicum and common lambsquarters at planting time averaged at least 95% for all early preplant and 92% for late preplant treatments. Where no preplant treatment was used, heavy weed growth in spring delayed soil dry-down, which resulted in poor ridge-till planting conditions and reduced plant stands, and ultimately reduced sorghum grain yields by 24% and soybean yields by 12%. Horsenettle population declined significantly, and honeyvine milkweed population increased. Smooth groundcherry populations fluctuated from year to year with no overall change.
Effect of pH on Phytotoxicity of Metribuzin and Ethyl-metribuzin
Authors: Peek Daniel C. , Appleby Arnold P.
Published: March 2018

The influence of pH on the behavior of metribuzin and ethyl-metribuzin in soil and nutrient solution was studied. Toxicity of both herbicides to oats decreased as soil pH decreased from 8.4 to 4.2 in a sandy loam. Herbicide adsorption increased as soil pH decreased. In nutrient solution, pH did not change the phytotoxicity of either herbicide, indicating that pH primarily influences herbicide availability in soil and not plant uptake.
Economic Evaluation of Wyoming Big Sagebrush (Artemisia tridentata) Control Methods
Authors: Watts Myles J. , Wambolt Carl L.
Published: March 2018

The economic feasibility of four Wyoming big sagebrush control methods: burning, spraying with 2,4-D, plowing and seeding, and rotocutting was analyzed. Perennial grass response to big sagebrush treatment was measured to estimate a treatment response function for each control method which provided the biological informational base to develop cost and benefits. Annualized present values of net additional returns for single 2,4-D and burning treatments were $1.10/ha and $1.16/ha, respectively. When big sagebrush was retreated at optimal intervals, 2,4-D and burning generated annualized net additional returns of $2.88/ha and $2.57/ha, respectively. Rotocutting was marginally feasible, and plowing was not feasible.
Construction of a High-Clearance Plot Sprayer
Authors: Chenault Ellis W. , Wiese Allen F.
Published: March 2018

Weed control research includes comparisons of herbicides, spray volumes, carriers, and application times in tall crops such as grain sorghum and corn. To accomplish this, a plot sprayer was constructed on a 15-kW tractor with 1.5-m clearance. Ten spray cans held spray mixes that were propelled by compressed air supplied by a two-cylinder single-stage compressor. Using this sprayer, two people could spray up to 66 plots per h to evaluate herbicides, growth regulators, and insecticides in tall weeds and crops using different speeds, controlled droplet applicators, rope wicks, or air-assist nozzles at low- and high-spray volumes.
Tolerance of Corn (Zea mays) to Sethoxydim Applied With Precision Postemergence-directed Sprayer Equipment
Authors: Kleppe Craig D. , Harvey Robert G.
Published: March 2018

The tolerance of 41- and 76-cm tall corn to sethoxydim applied with a precision postemergence-directed sprayer was evaluated in field studies in 1987 and 1988. Corn 41 cm tall at application tolerated directed sethoxydim more than corn 76 cm tall. Sethoxydim plus crop oil concentrate at 110 to 220 g/ha plus 1.3% (v/v) applied to 41-cm corn resulted in little or no injury and no corn grain yield reductions. When sethoxydim at rates exceeding 110 g/ha plus crop oil concentrate was applied to corn 76 cm tall, injury occurred which reduced corn grain yield. Good tolerance of 41-cm tall corn validates the safety and effectiveness of postemergence-directed sethoxydim when applied with precision sprayer equipment.
Effect of Ammonium Sulfate and Bentazon on Sethoxydim Absorption
Authors: Jordan David L. , York Alan C. , Corbin Frederick T.
Published: March 2018

The effect of ammonium sulfate on absorption of14C-sethoxydim applied alone and with bentazon was studied in large crabgrass. Adding ammonium sulfate to14C-sethoxydim increased14C absorption 6-fold at 0.5 h after application but did not affect the amount of14C absorbed 1 or 4 h after application. Applying bentazon with14C-sethoxydim reduced14C absorption 26%. When14C-sethoxydim was applied with bentazon and ammonium sulfate,14C absorption and translocation were similar to those with14C-sethoxydim alone.
Chemical Control of Mayweed Chamomile (Anthemis cotula) in Winter Wheat (Triticum aestivum)
Authors: Kells James J.
Published: March 2018

Field trials were conducted in 1985, 1986, and 1987 to identify effective herbicide treatments to control mayweed chamomile in winter wheat. Dicamba at 280 g ae/ha, 2,4-D at 560 g ae/ha, and bromoxynil at 560 g ai/ha did not control 11-cm-tall or larger mayweed chamomile and inconsistently controlled smaller plants. Mayweed chamomile control generally declined with increasing weed size. DPX-M6316 at 8.8 g ai/ha and DPX-L5300 at 4.4 g ai/ha controlled 89% or more mayweed chamomile. CGA-131036 at 4.9 g ai/ha controlled 95% or more mayweed chamomile. DPX-M6316, DPX-L5300, and CGA-131036 controlled 3- to 18-cm-tall mayweed chamomile similarly.
Interference with Loblolly Pine (Pinus taeda) Seedling Growth by Three Grass Species
Authors: Smith Albert E.
Published: March 2018

The growth of loblolly pine seedlings was reduced by interference from bermudagrass, tall fescue, and broomsedge. The order for treatment influence on pine seedling growth rate measurements was tall fescue > bermudagrass > broomsedge > weed free for the 2-yr study. The increase in height of seedlings for the weed free, broomsedge, bermudagrass, and tall fescue was 4.1, 2.9, 1.9, and 1.1 cm/month, respectively; and the average increase in seedling stem diameter was 1.3, 0.5, 0.4, and 0.2 mm/month, respectively.
Common Mullein – the Roadside Torch Parade
Authors: Notch Larry W.
Published: March 2018

Common mullein (Verbascum thapsus L. ♯3 VESTH) has an ancient relationship with man. It never has been used for food but traditionally has been respected for its mystical and medicinal powers.
Twenty-year Control of California False-hellebore
Authors: Williams M. Coburn
Published: March 2018

Experimental plots treated with 2,4-D amine at 2.2 kg ae ha-1in 1968 and 1969 to control California false-hellebore were evaluated in July 1989 to determine long-term control of California false-hellebore, changes in foliar cover, and increases in production of desirable species. Control of California false-hellebore was 100% on all treated plots. The foliar cover on treated plots averaged 78% grasses and sedge, 20% broadleaf plants, and no California false-hellebore. Control plots averaged 85% California false-hellebore, 10% grasses and sedge, and 4.5% broadleaf plants. Vegetative production of grasses and sedge was 3.8 times greater on treated plots compared with controls.
Alternatives for Control of Paraquat Tolerant American Black Nightshade (Solanum americana)
Authors: Bewick Thomas A. , Stall William M. , Kostewicz Stephen R. , Smith Kenneth
Published: March 2018

Greenhouse and field experiments were conducted to identify alternative herbicide treatments for the control of a biotype of American black nightshade which has been shown to tolerate paraquat. In greenhouse experiments the combination of paraquat and the metal chelator diethyldithiocarbamate at either 1% w/v or 3% w/v, and diquat alone significantly lowered I50values, based on dry weight, when compared with paraquat alone. None of these treatments provided acceptable control (>90%) in field experiments. Treatments that controlled American black nightshade under field conditions were: monocarbamide dihydrogensulfate at 9 kg ai ha-1, monocarbamide dihydrogensulfate at 9 kg ha-1+ paraquat at 0.6 kg ha-1, lactofen at 0.6 kg ha-1, oxyfluorfen at 0.6 kg ha-1, and acifluorfen at 0.6 kg ha-1. Addition of tridiphane at 1.7 kg ha-1to paraquat at 0.6 kg ha-1did not improve control of American black nightshade under field conditions.
Early Preplant Atrazine and Metolachlor in Conservation Tillage Corn (Zea mays)
Authors: Buhler Douglas D.
Published: March 2018

Field research was conducted at Arlington, WI in 1984 and 1985 to determine the influence of application timing on weed control with atrazine and metolachlor in conservation tillage corn production systems. Early preplant treatments controlled fewer weeds than preemergence or early preplant/preemergence sequential treatments in a chisel plow system. Velvetleaf control was only 50% late in the growing season with early preplant atrazine compared with 88% with an early preplant/preemergence sequential treatment of the same amount of atrazine. In the no-till system, early preplant applications of atrazine and/or metolachlor had reduced weed control late in the growing season compared with preemergence and early preplant/preemergence sequential treatments of the same amount of herbicide. Giant foxtail control 110 d after corn planting was only 73% with an early preplant treatment compared with 99% when the same amount of herbicide was evenly divided between early preplant and preemergence applications.
Effect of Haloxyfop on Quackgrass (Elytrigia repens) and Potatoes (Solanum tuberosum)
Authors: Ivany Jerry A.
Published: March 2018

Reduction of initial top growth of quackgrass with haloxyfop at 0.13 kg ai ha-1and above in the greenhouse was comparable at the 2-, 4-, and 6-leaf stages. Quackgrass control was not affected by rhizome length in plants grown from 2-node and 10-node rhizome pieces. Removal of quackgrass shoots 6 h after treatment resulted in increased initial topgrowth, regrowth, and rhizome weight at all application rates when compared to treatments with no removal of shoots; however, growth decreased with increasing rates of haloxyfop. Later removal at 24 or 96 h after treatment did not affect quackgrass control, indicating rapid translocation. In field-grown potato, haloxyfop applied at 0.25 kg ha-1at the 4- to 5-leaf stage controlled more than 80% of quackgrass. Lower rates controlled less than 80% when used alone; but adding cultivation improved control. No adverse effect on potato yield was noted with haloxyfop.
Weed-Crop Responses to Weed Management Systems in Conservation Tillage Corn (Zea mays)
Authors: Coffman C. Benjamin , Frank J. Ray
Published: March 2018

Continuous corn was grown for 5 consecutive yr using conservation tillage methods in the Maryland Piedmont. Herbicide treatments were applied annually at common usage rates and were compared for their effects on weed cover, species stability, and grain production. Weed flora dominance shifted from giant foxtail the first year to smooth pigweed the following year. Smooth pigweed then dominated the flora for the duration of the study. Horsenettle was ubiquitous in all treatments but never became competitive. Canada thistle occurred in measurable densities in all plots that had not received atrazine applied preemergence. Grain yields were correlated negatively with densities of smooth pigweed in 1983 (r = −0.58, P = 0.01), and Canada thistle in 1983 and 1984 (r = −0.63 and −0.62, respectively; P = 0.05). Grain yields were correlated positively with midseason precipitation (r = 0.85, P = 0.01).
Johnsongrass (Sorghum halepense) Control in Soybeans (Glycine max) with Postemergence Herbicides
Authors: Johnson William G. , Frans Robert E.
Published: March 2018

Field studies were conducted in 1987 and 1988 at Fayetteville and Clarkedale, AR, to evaluate various herbicide treatments for johnsongrass control in soybeans. Herbicide treatments were postemergence applications of sethoxydim, fenoxaprop, fluazifop-P, haloxyfop, quizalofop, imazethapyr, and clethodim. No significant soybean injury was noted in 1987 or 1988 at either location in the johnsongrass experiments. All treatments except those with fenoxaprop and imazethapyr, provided 70 to 90% johnsongrass control. Generally, soybean yields were reduced from treatments that controlled less than 60% of the johnsongrass.
Application Timing of Herbicides for the Control of Redvine (Brunnichia ovata)
Authors: Shaw David R. , Mack Robert E.
Published: March 2018

Field experiments were conducted in 1986 and 1987 to determine the efficacy of various herbicides applied in the spring or fall for redvine population reductions. Spring applications of dicamba and picloram reduced redvine populations 4 mo after application. These treatments also reduced soybean density. A sequential spring followed by fall application of dicamba reduced redvine stem counts 32 to 45% the following year. Spring or spring followed by fall applications of clopyralid and hexazinone were not effective in reducing redvine populations. A fall application of clopyralid, dicamba, Dowco 433, glyphosate, or imazapyr reduced redvine regrowth 78 to 97% the following year. Dicamba at 2.2 kg ae ha-1, 3.4 kg ae ha-1glyphosate, and 0.28 kg ai ha-1imazapyr increased soybean yield the following year because of reduced redvine competition and lack of herbicide injury. Redvine populations were unaffected by fall applications of fosamine, hexazinone, and picloram, or clomazone applied in the spring or in the fall followed by a sequential spring application. A sequential spring followed by fall treatment of 1.1 + 1.1 kg ha-1dicamba or 0.14 + 0.14 kg ae ha-1clopyralid reduced trumpetcreeper population 49 to 58% the following year.
Palmer Amaranth (Amaranthus palmeri) Control in a Conservation Tillage System for Cotton (Gossypium hirsutum)
Authors: Keeling J. Wayne , Siders Kerry T. , Abernathy John R.
Published: March 2018

Weed control is a limiting factor for adoption of conservation tillage systems on the Texas Southern High Plains. A field study was established to evaluate Palmer amaranth control with strip-tillage dinitroaniline herbicide incorporation in wheat residue. Preemergence herbicides were applied alone and in combination with strip-tilled incorporated herbicides. Significant cotton injury or stand reductions were not observed with any treatment. Effective (>80%) early season Palmer amaranth control was achieved with trifluralin or pendimethalin in conjunction with preemergence herbicides. Preemergence herbicides alone did not provide adequate control.
Paraquat for Managing Weeds in Alfalfa (Medicago sativa)
Authors: Smith Albert E.
Published: March 2018

Experiments were conducted over 2 yr and at two locations in Central Georgia to determine the influence of paraquat applied for weed control in the spring and following first harvest on alfalfa yield and crown carbohydrate content. Paraquat at 0.28 and 0.56 kg ai ha-1controlled most annual cool-season weeds at 20 d after March treatment. These rates controlled annual warm-season weeds when applied as early as 7 d after first harvest. Treatments applied during March and as late as 7 d after first harvest did not influence alfalfa production or crown carbohydrate content. However, paraquat applied 14 d after first harvest reduced alfalfa yield 40% and significantly decreased crown carbohydrate content at second harvest but the alfalfa had fully recovered by the third harvest. This indicates that alfalfa is resilient to chemical defoliation by paraquat applied for weed control.
Postemergence-Directed Sprayers for Wild-Proso Millet (Panicum miliaceum) Control
Authors: Kleppe Craig D , Harvey Robert G.
Published: March 2018

Several precision postemergence-directed sprayers with different nozzle designs and arrangements were evaluated for potential use in sweet corn for wild-proso millet (PANMI) control in field trials from 1987 to 1989. Ametryn at 2270 g ha-1plus oil-emulsifier mixture (OEM) at 1.3% v/v and sethoxydim alone or plus OEM applied postemergence-directed selectively controlled PANMI in sweet corn. Sethoxydim at 220 g ha-1plus OEM controlled PANMI best when averaged over the 3-yr period. Ametryn plus OEM did not injure corn and sethoxydim at 110 g ha-1plus OEM caused little or no corn injury and no yield reductions when applied with any of the sprayers. Generally, only sethoxydim at 220 g ha-1plus OEM injured corn. The amount of injury was different among sprayers, with the nozzle designs and arrangements responsible for corn injury. Injury was minimized when sethoxydim was applied with a sprayer equipped with 150 degree dual orifice nozzles spaced 38 cm apart and mounted on skids that contacted the soil to assure constant nozzle height. This sprayer, or sprayers of similar nozzle design, show the most potential for use by sweet corn growers.
Response of Yankeeweed (Eupatorium compositifolium) and Associated Pasture Plants to Herbicides
Authors: Meyer Robert E. , Bovey Rodney W.
Published: March 2018

Eleven herbicides applied in May, were evaluated for yankeeweed control in East-Central Texas. Yankeeweed cover 1 yr later was reduced to 5% or less by 0.28 kg ha-1 of picloram; 0.56 kg ha-1 of clopyralid, glyphosate, or dicamba; 0.28 + 0.84 kg ha-1 of dicamba + 2,4-D, and 1.1 kg ha-1 triclopyr compared with 30% cover in the untreated area. Chlorsulfuron and metsulfuron at 0.07 kg ha-1 reduced yankeeweed cover to 12 and 7%, respectively. Dalapon, 2,4-D, and tebuthiuron were relatively ineffective. Most herbicides, reduced woolly croton cover within 1 mo after treatment compared to the untreated areas, but 2,4-D at 0.28 kg ha-1 and chlorsulfuron at 0.02 kg ha-1 and 0.07 kg ha-1 were most effective after 4 mo. All herbicides, except dalapon at 1.1 kg ha-1 or less and most rates of 2,4-D and tebuthiuron, reduced partridgepea cover during the year of application. Total grass cover was increased 4 and 12 mo following treatment with clopyralid, picloram, dicamba, and triclopyr. On separate sites, bahiagrass and coastal bermudagrass accounted for most of the increased grass cover.
Survey and Control of Musk Thistle (Carduus nutans) in Tennessee Field Nurseries
Authors: Monks David W. , Halcomb Mark A. , Ashburn Elmer L.
Published: March 2018

Grower response from a mail survey indicated that musk thistle is a common and spreading problem in Tennessee nurseries. Poor herbicide selection and timing were reasons for the lack of control in most nurseries. At 31 wk after treatment preemergence herbicides or herbicide mixtures that gave 80% or greater musk thistle control in evaluation studies were atrazine, simazine, simazine + metolachlor (1.1 + 4.4 kg ai ha-1), oryzalin + isoxaben, or dithiopyr. Oryzalin, metolachlor, napropamide, or simazine + metolachlor (0.5 + 2.2 kg ha-1) gave 65, 35, 0 and 78% control of musk thistle, respectively. Glyphosate or SC-0224 at 1.7 and 2.2 kg ha-1gave 89% or greater control of emerged musk thistle. Lactofen or HOE-39866 at 0.8 kg ha-1gave less than 66% control of emerged musk thistle at 8 wk after treatment.
Wheat (Triticum aestivum) Cultivar Tolerance and Italian Ryegrass (Lolium multiflorum) Control with Diclofop, BAY SMY 1500, and Metribuzin
Authors: Shaw David R. , Wesley M. Todd
Published: March 2018

In the field, 14 soft red winter wheat cultivars responded differently to 1.1 kg ai ha–1diclofop, 1.7 kg ai ha–1BAY SMY 1500, and 0.42 kg ai ha–1metribuzin applied POST. Diclofop and metribuzin did not injure any cultivar more than 10% on a silty clay soil. However, BAY SMY 1500 injured ‘Pioneer 2551’ and ‘Coker 983’ 39 and 21%, respectively, in March. All other cultivars were injured less than 10% by BAY SMY 1500. Early injury did not translate into yield loss in the cultivar tolerance study. In an application timing study for Italian ryegrass control, late-season ratings indicated better control with two-leaf applications than with PRE applications for all treatments. Delaying application to the three-tiller stage reduced control with BAY SMY 1500 or metribuzin, but not with diclofop. On the sandier soil at this location, wheat injury with 0.28 or 0.43 kg ha–1metribuzin or 2.2 kg ha–1BAY SMY 1500 was sufficient to reduce wheat yield compared with other treatments, despite good Italian ryegrass control.
Tropic Croton (Croton glandulosus) Control in Peanut (Arachis hypogaea)
Authors: Wilcut John W.
Published: March 2018

Field studies in 1988 and 1989 evaluated POST herbicides alone and in tank-mixtures for tropic croton control in peanut. Acifluorfen + 2,4-DB, acifluorfen + bentazon, acifluorfen + bentazon + 2,4-DB controlled > 90% of tropic croton when applied at 2 or 4 wk after crop emergence. Paraquat + bentazon controlled 55% at 2 wk and 24% at 4 wk after crop emergence. Imazethapyr and imazethapyr + 2,4-DB controlled < 24% tropic croton at either 2 or 4 wk after crop emergence. Acifluorfen + 2,4-DB, acifluorfen + bentazon, and acifluorfen + bentazon + 2,4-DB controlled at least 90% of the common lambsquarters, common ragweed, and morningglory species. Greatest yields and net returns were obtained with acifluorfen + bentazon + 2,4-DB applied 2 wk after crop emergence. Yields were higher with acifluorfen + bentazon + 2,4-DB and imazethapyr applied at 2 wk after crop emergence than at 4 wk after crop emergence. All other herbicide treatments provided equivalent yields among application timings. Only acifluorfen + 2,4-DB provided equivalent net returns at either application timing. All other herbicide treatments provided lower net returns with applications made at 4 wk than at 2 wk after crop emergence.
Tridiphane Enhances Wild Oat (Avena fatua) Control by Atrazine-Cyanazine Mixtures
Authors: Ahrens William H. , Ehr Robert J.
Published: March 2018

Wild oat, a competitive weed in corn, can be controlled by atrazine applied postemergence but at rates causing carryover problems on high pH soils rotated to susceptible crops. Experiments at Fargo, ND and Barnesville, MN were established in corn using atrazine rates ranging from 0.14 to 0.84 kg ai ha–1supplemented with cyanazine to provide 1.68 kg ai ha–1total triazine herbicide. Atrazine at 0.84 kg ha–1plus cyanazine at 0.84 kg ha–1controlled 2- to 3-leaf wild oat 40 to 55%, but control increased to 90 to 95% by adding tridiphane at 0.56 or 0.84 kg ai ha–1. In greenhouse experiments, tridiphane synergistically increased wild oat control by atrazine and cyanazine. Tridiphane applied 1 or 2 d before atrazine or before an atrazine-cyanazine mixture generally controlled wild oat similar to the tridiphane-triazine tank mix.
Red Rice (Oryza sativa) Control and Suppression in Rice (O. sativa)
Authors: Kwon Sam L. , Smith Roy J. , Talbert Ronald E.
Published: March 2018

Two field experiments were conducted from 1986 to 1988 to determine efficacy of herbidices and plant growth regulators for red rice control and suppression in water- and drill-seeded rice. Molinate applied PPI with fenoxaprop applied at panicle initiation (PI) of rice controlled 94 and 86% of red rice in water- and drill-seeded rice, respectively, compared with 79 and 49%, respectively, for molinate PPI alone in the two cultures. Although this treatment injured rice slightly (< 30%), rice so treated produced high yields with improved grain quality. Sequential treatments of molinate PPI followed by sethoxydim applied at PI or amidochlor applied at > 90% heading produced comparable rice yields with improved red rice control or suppression and grain quality in both cultures, compared with PPI molinate. Drill-seeded rice treated with molinate PPI followed by fenoxaprop applied at late boot or MH (maleic hydazide) applied 7 d after heading produced higher yield than rice treated with molinate PPI.
A Sprayer for Small Plots in a Randomized Design
Authors: Phelps Jay B.
Published: March 2018

Application of crop protection compounds to randomized small plots with motorized sprayers can be a cumbersome process for field researchers. A motorized, high clearance spraying system has been developed that allows precise application of spray mixtures to randomized plots without driving along alleys between blocks or changing sprayate bottles between treatments. A description of the spraying system is given.
Enhanced Activity of Single-Isomer Fenoxaprop on Cool-Season Grasses
Authors: Mueller-Warrant George W.
Published: March 2018

Formulations of fenoxaprop enriched in the R(+) isomer, HOE 46360-08H EW (described as an emulsifiable water-based formulation) and HOE 46360-05H EC (emulsifiable concentrate), were compared with the commercial racemate EC for control of roughstalk bluegrass and tolerance of perennial ryegrass and tall fescue grown for seed. The enriched EW and EC formulations were more than twice as active as the racemate per kg total fenoxaprop, despite enrichment to only 92 and 89% R(+) isomer purity, which should have increased activity by 1.84- and 1.78-fold, respectively. Increased activity was evident both as improved weed control and as decreased crop tolerance. Although the 3.69-fold increase in activity of HOE 46360 EW on roughstalk bluegrass relative to the racemate may be partly due to changes in the emulsion, the 3.06-fold increase in activity of HOE 46360 EC suggests that the S(-) isomer somehow interferes wih the activity of the R(+) isomer. Use of 280 g ai ha–1of the racemate could be replaced with 76 g ha–1of the EW or 92 g ha–1of the EC formulation of HOE 46360 for equivalent roughstalk bluegrass control, but with decreased crop tolerance in perennial ryegrass and tall fescue.
Critical Weed-Control Period in Seeded Cabbage (Brassica oleraceavarcapitata)
Authors: Miller Alan B. , Hopen Herbert J.
Published: March 2018

The critical weed-control period in field seeded cabbage using natural weed stands was 2 wk in 1988 and 4 wk in 1989. Regression analysis showed that the length of weed-free period, weed density, and ambient light reduction by competing weeds were factors affecting cabbage yield. Weeds that emerged after the initial weed-free period shaded the soil and subsequently lowered soil surface temperatures in 1989. Velvetleaf densities of 1.2 and 3.6 plants per m2that competed all season with cabbage reduced cabbage yields 52% and 71% of the weed-free treatment in 1988 and 76% and 92% in 1989, respectively. Cabbage yields were reduced at all velvetleaf densities seeded 0, 1, and 2 wk after cabbage, but cabbage yield was not reduced when velvetleaf was seeded 4 or 6 wk after cabbage. Cabbage yield was not different between parallel and staggered velvetleaf configurations at 0.6 plants per m2, but was reduced with longer periods of competition. Velvetleaf seed production was prevented with 6 wk weed-free period after cabbage emergence and subsequent destruction of emerging velvetleaf after cabbage harvest.
Leafy Spurge (Euphorbia esula) Response to Single and Repetitive Picloram Treatments
Authors: Hein David G. , Miller Stephen D.
Published: March 2018

A 4-yr field study was conducted near Grassrange, MT to determine the effects of single and repetitive picloram treatments for leafy spurge control in a native pasture. Single applications of picloram at 0.28, 0.56, 0.84, and 1.12 kg ae ha–1averaged 0, 5, 22, and 61% leafy spurge shoot control 3 yr after treatment. Only the single applications of picloram at 1.68 and 2.24 kg ha–1maintained leafy spurge control above 80%. A retreatment with 0.56 kg ha–1picloram was required to maintain effective control for 3 yr when less than 1.68 kg ha–1was applied. Leafy spurge canopy cover in the 1.68 and 2.24 kg ha–1treatments averaged 14 and 6% 3 yr after treatment; however, all other single applications required retreatment.
Residues and Efficacy With Fluazifop-P in Alfalfa (Medicago sativa)
Authors: Doohan Douglas J. , Belanger Gilles , King Russ R. , Ivany Jerry A.
Published: March 2018

Fluazifop-P, applied in the spring or fall and pronamide, applied in the fall only, reduced quackgrass infestation in established alfalfa and increased the dry matter yield of alfalfa. Herbicides did not improve alfalfa in vitro digestibility or crude protein content. Average residues of fluazifop-P in alfalfa treated with rates of 0.25 or 0.5 kg ai ha–1, were 0.1 mg kg–1when harvested 280 d after application, and 0.06 mg kg–1when harvested 295 d after application. Average residues in alfalfa harvested 41 and 55 d after application were 0.13 mg kg–1and 0.1 mg kg–1, respectively, with a 0.25 kg ha–1treatment and 0.19 mg kg–1and 0.05 mg kg–1, respectively, with a 0.5 kg ha–1treatment.
Cotton (Gossypium hirsutum) Yield Response to Cultivation Timing and Frequency
Authors: Snipes Charles E. , Colvin Daniel L. , Patterson Michael G. , Crawford Stephen H.
Published: March 2018

A four-state study was initiated in 1988 to evaluate the influence of cultivation frequency and initiation on the cotton plant. When cultivations were initiated at 1 or 2 wk after emergence and cultivated weekly at a frequency of zero, one, two, four, or six times, seed cotton yields were not affected on a consistent basis. When averaged over cultivation frequency, seed cotton yields were increased for three of nine year-locations when cultivations were initiated at 2 wk after emergence when compared with 1 wk after emergence. At two locations, when seed cotton yields were averaged over initiation timing, it was shown that only two cultivations were necessary to achieve optimum seed cotton yields.
Early Season Herbicide Applications for Weed Control in Stale Seedbed Soybean (Glycine max)
Authors: Bruff Stacey A. , Shaw David R.
Published: March 2018

Field experiments were conducted in 1989 and 1990 on silty clay and sandy loam soils to evaluate weed control and soybean yield with early-April preplant incorporation of selective herbicides in stale seedbed soybean followed by non-selective weed control measures at planting. Metribuzin applied PPI early followed by chlorimuron POST coupled with either glyphosate or paraquat PRE controlled sicklepod, pitted morningglory, and hemp sesbania to the same extent of that treatment applied PPI at planting. All stale seedbed treatments with POST applications and glyphosate, paraquat, or tillage at planting controlled pitted morningglory over 70%. However, imazaquin or metribuzin applied PPI early without a POST treatment controlled sicklepod and pitted morningglory poorly. Frequently, applying PPI herbicides at planting increased control compared with early PPI applications, but this was overcome by POST treatments. Early stale seedbed applications of metribuzin did not result in more than 60% control of hemp sesbania, whereas metribuzin applied PPI at planting controlled over 85%. However, metribuzin plus chlorimuron controlled hemp sesbania at least 74%, regardless of application timing or tillage method, whereas no imazaquin treatment achieved over 65% control. All stale seedbed herbicide treatments increased soybean yield compared with the untreated stale seedbed check. Selective herbicide treatments with either non-selective herbicide in a stale seedbed program resulted in equivalent yield to PPI at planting treatments most often, except with metribuzin.
Soybean (Glycine max) and Rotational Crop Tolerance to Chlorimuron, Clomazone, Imazaquin, and Imazethapyr
Authors: Krausz Ronald F. , Kapusta George , Knake Ellery L.
Published: March 2018

Tolerances of soybean and rotational crops wheat and corn to chlorimuron (0.02 to 0.14 kg ai ha–1), clomazone (0.56 to 3.36 kg ha–1), imazaquin (0.07 to 0.42 kg ha–1) and imazethapyr (0.05 to 0.31 kg ha–1) were evaluated in field studies. No visible soybean injury was observed. No reduction in soybean population, height, or yield occurred from the use of these herbicides, in 1986 or 1987. Differences in wheat yields among treatments were not significant in 1987 or 1988. Corn population, number of ears, ear weight, or yield were not different.
Sweet Corn (Zea mays) Hybrid Tolerance to Nicosulfuron
Authors: Morton Cathy A. , Harvey R. Gordon
Published: March 2018

Tolerance of eight processing sweet corn hybrids to nicosulfuron was evaluated in field studies conducted at Arlington, Wis. in 1988 and 1989. Magnitude of sweet corn vigor reduction varied between years. Greater vigor reduction occurred to ‘Jubilee’ sweet corn than to the other seven hybrids. Injury to the hybrids increased as nicosulfuron rate increased. In 1988, some of the hybrids were stunted slightly by all of the herbicide rates, but within a hybrid there was no significant difference among herbicide rates. In 1989 none of the hybrids, including Jubilee, was stunted by even 140 g ai ha–1nicosulfuron compared with the corresponding check. Effects of nicosulfuron on yields of the eight hybrids in 1988 and in 1989 are best described by a quadratic regression equation.
Yellow Nutsedge (Cyperus esculentus) Control in Peanuts (Arachis hypogaea)
Authors: Grichar W. James
Published: March 2018

Field studies were conducted from 1986 through 1988 to evaluate various herbicides for yellow nutsedge control and peanut yields. Three applications of pyridate provided control comparable to two applications of bentazon with yellow nutsedge regrowth beginning 3 to 4 wk after application depending on moisture conditions. Crop oil concentrate did not improve the activity of pyridate. Flurtamone provided control comparable with that of metolachlor. Nutsedge control with fomesafen was erratic with peanut injury noted. Peanut yields did not reflect the competitive nature of nutsedge.
Weed Control for Soybean (Glycine max) Planted in a Stale or Undisturbed Seedbed on Clay Soil
Authors: Heatherly Larry G. , Elmore C. Dennis , Wesley Richard A.
Published: March 2018

Field studies were conducted for three consecutive years to determine if PRE and/or POST herbicides were needed in addition to preplant foliar-applied glyphosate and POST cultivation for maximum seed yield of irrigated and nonirrigated soybean planted in stale and undisturbed seedbeds on clay soil. Soybean seed yields following the use of PRE and POST herbicides alone or in combination were similar in all years, and exceeded seed yield following the use of glyphosate plus POST cultivation only. Plantings made in no-till and fall-till seedbeds produced similar seed yields when both PRE and POST herbicides were used. These results indicate that glyphosate plus cultivation was not adequate for soybean in stale seedbed plantings, and that either PRE or POST herbicides, but not both, were required for maximum seed yield.
Postemergence Control of Wild Garlic (Allium vineale) in Turfgrass
Authors: Ferguson Gregory P. , Coats G. Euel , Wilson Galen B. , Shaw David R.
Published: March 2018

Experiments were conducted to evaluate imazaquin and selected herbicides for POST control of wild garlic. At the same dosages, imazaquin applied in late November/early December (late fall) controlled wild garlic better than when applied in early March (late winter) when assessed in May. Imazaquin provided control equivalent to 1120 g ae ha–12,4-D plus imazaquin. Imazapyr, imazamethabenz, or imazethapyr at 280, 1120, or 560 g ai ha–1, respectively, provided control equivalent to 560 g ai ha–1imazaquin. Thifensulfuron at 70 g ai ha–1provided better control applied in late winter (85%) than late fall (45%). All herbicides consistently provided better control than 2,4-D plus mecoprop plus dicamba, except thifensulfuron applied in late fall, at the final evaluation. Common bermudagrass growth in early spring was delayed 2 mo by ≥ 560 g ha–1imazaquin, 70 g ha–1thifensulfuron, imazethapyr, and imazapyr or 2,4-D plus mecoprop plus dicamba applied in late winter. Imazamethabenz did not delay common bermudagrass growth. Late fall applications of 1120 g ha–1imazaquin did not delay growth while ≥ 560 g ha–1imazethapyr delayed common bermudagrass growth through April.
Costs Associated with Weed Management in Cereals and Food Legumes in the Chaouia Region of Settat Province, Morocco
Authors: Zimdahl Robert L. , Rafsnider Giles T. , Boughlala Mohamed , Laamari Abdellila
Published: March 2018

Crop enterprise budgets for eight crops prepared from a sample of 131 farms in the Chaouia region of Settat province, Morocco show that weed management is a component of crop production. Although all farmers used herbicides on small grains, weed control was accomplished primarily with hired and family labor. In general, labor is more plentiful than capital and the per hectare cost of using hired labor is low. The percentage of total cash expenditures assigned to weed management averaged more than 5% in each farm size group. However, there was substantial variability among crops. Average hours spent to manage weeds was nearly constant for the three groups. Barley received the least labor and corn or a food legume the most. Farmers of small farms used more family labor and those of large farms used more hired labor.
Teaching Weed Science in the Future
Authors: Thill Donald C.
Published: March 2018

Weed science has been and will continue to be an evolving discipline. The evolution and future of weed science will depend greatly on our visions of the future and our willingness to effect and implement change. Thus, the principal question we must ask ourselves is, what do we want weed science to be in the future? This paper, which is only one part of the symposium on the Future of Weed Science, will address the issues involved with teaching. This requires identification of future students and employers, their educational needs based on professional goals, and packaging and presenting the information. Most future agriculture undergraduates and weed science graduate students will need to be recruited, will have minimal background in agriculture, and will include more minorities and women than in the past. We will offer a more interdisciplinary and internationalized curriculum to future students. The curriculum will include traditional courses with greater emphasis on communication skills, business and economics, computer science, agricultural ethics, and interpersonal skills. Courses will be taught to future students by a regional teaching concept that uses electronic media. Teaching and learning about weed science in the future will be exciting, challenging, and unquestionably different from today.
The Role of Industry in the Future of Weed Science
Authors: Harr Jost
Published: March 2018

The agricultural-chemical industry has been offering solutions in plant protection for several decades. The primary role of Industry in weed control has mainly been to provide chemicals with increasingly attractive profiles regarding safe handling, ecological acceptance, and economical attractiveness. These objectives have been reached by significant developments, e.g. in rates, persistence, and specificity for non-target organisms. It is therefore safe to assume that in the year 2015 and beyond chemicals will continue to maintain a major role in weed control. However, as cropping systems and criteria for desirable control levels change, industry will have to change from a re-active to a pro-active participant in the development of integrated systems. Chemical solutions will be complemented by biological and agronomical methods and will be further supported by biotechnological successes in the crop area. In addition, it is anticipated that sophisticated computer models now in development will help exploit the potential of products as well as of integrated systems. Thus, fully integrated companies active in chemical, biological, and molecular-biological research and having branches in the agro-chemical as well as in the seed business will be especially suited to be driving forces in the changing world of modern weed control. The practice will ask for services much more than for single products. Industry will not only have to offer those services but at the same time assist in the education of growers to enable efficient use of the increasingly intricate methods of future weed control.