bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficacy of Selected Herbicides as Influenced by Soil Properties
Authors: Blumhorst Michael R. , Weber Jerome B. , Swain Len R.
Published: March 2018

Field experiments were conducted on six loam and sandy loam soils to study the influence of various soil parameters on atrazine, cyanazine, alachlor, metolachlor, and pendimethalin efficacy. Herbicidal activity was highly correlated to the soil organic content. Humic matter content was equally or better correlated (r = 0.70 to 0.91) with herbicide bioactivity than was organic matter content (r = 0.66 to 0.84). Regression equations were determined which allow herbicide rate recommendations for 80% weed control to be calculated based on soil humic matter or organic matter levels.
Effect of Rate, Carrier Volume, and Surfactant on Imazamethabenz Efficacy
Authors: Brewster Bill D. , Appleby Arnold P.
Published: March 2018

Imazamethabenz is a selective herbicide used to control wild oat in small grains. The effects of rate, volume of carrier, and surfactant concentration on the efficacy of this herbicide in controlling wild oat were studied in field experiments. As each of the variables increased, wild oat control increased; the greatest degree of wild oat growth inhibition occurred at the highest herbicide rate, highest volume of carrier, and highest surfactant concentration.
Effect of Soil Type, Hilling Time, and Weed Interference on Potato (Solanum tuberosum) Development and Yield
Authors: Vangessel Mark J. , Renner Karen A.
Published: March 2018

‘Atlantic’ and ‘Russet Burbank’ potato cultivars were grown on mineral and organic soils either with or without weeds and were hilled at two stages of potato development (potatoes cracking through the soil and potatoes 30 cm tall). A single hilling procedure was not adequate in either year for full-season weed control. Early hilling suppressed weeds and increased tuber yields more than conventional hilling on mineral soils in 1988 only. Early hilling tended to increase the relative biomass of C4weeds compared to C3weeds for both soils. Weeds reduced aboveground potato biomass on mineral and muck soils. However, reduced aboveground potato biomass measurements did not predict tuber yield reductions. Marketable yield of Russet Burbank potato was reduced by weed interference more than the yield of Atlantic on mineral soils when planted according to conventional cultural practices. However, the marketable yield of Atlantic potato was reduced more than Russet Burbank yield by weeds on muck soils. Weed interference influenced tuber quality on both mineral and muck soil.
Effects of Chlorimuron Applied Postemergence to Cotton (Gossypium hirsutum)
Authors: Patterson Michael G. , Monks C. Dale , Rayburn Thomas , Wehtje Glenn
Published: March 2018

Chlorimuron applied postemergence at 2.2, 4.4, 8.8, 18, and 35 g ai/ha to cotton at either the 4-leaf, pinhead-square, first-bloom, or full-bloom growth stage was evaluated for potential as a plant growth regulator. Chlorimuron did not reduce bolls per plant at any rate or time of application, but the proportion of open to closed bolls decreased as rate increased. Seed cotton yields decreased with increasing chlorimuron rate and cotton age. The use of chlorimuron as a plant growth regulator for cotton appears limited.
Primary Tillage for Foxtail Barley (Hordeum jubatum) Control
Authors: Donald William W.
Published: March 2018

Primary tillage is an inexpensive method to control foxtail barley, a perennial bunchgrass which is an increasing concern to no-till cereal farmers in the Northern Great Plains. Moldboard plowing or chisel plowing in fall followed by field cultivation-harrowing in spring effectively controlled established foxtail barley on previously untilled sites before planting spring wheat. In contrast, chisel plowing in spring followed by field cultivation-harrowing did not control this weed completely.
Effects of Pronamide on Spring Transition of a Bermudagrass (Cynodon dactylon) Green Overseeded With Perennial Ryegrass (Lolium perenne)
Authors: Johnson Billy J.
Published: March 2018

Pronamide was applied to a ‘Tifway’ bermudagrass golf green overseeded with perennial ryegrass during 1988 and 1989 to determine how herbicide rate and date affected ryegrass injury on transition back to a bermudagrass monostand. In most instances, perennial ryegrass was injured less when pronamide was applied at 0.28 or 0.56 kg ai/ha March 30 or April 13 than when application was delayed until April 28 or May 14. Perennial ryegrass injury lasted longer when 0.28 kg/ha was applied twice (March and/or April) than when applied singly at 0.28 kg/ha March 30 or April 13. The optimum time and rate of pronamide for effective transition was April 13 and 0.56 kg/ha, respectively.
Effect of Atrazine and Tillage on Alfalfa (Medicago sativa) Establishment in Corn (Zeaways)-AlfaIfa Rotation
Authors: Kells James J. , Leep Richard H. , Tesar Milo B. , Leavitt Richard A. , Cudnohufsky John
Published: March 2018

The effect of atrazine rate and subsequent tillage on seedling alfalfa injury from atrazine carry-over was examined at two locations in Michigan. Atrazine concentration and alfalfa injury 1 yr after treatment were greater in the northern location than in the central Michigan location. At both locations, alfalfa injury was significantly greater under no-tillage than moldboard plowing. With no-tillage, alfalfa was injured more in the area between the previous corn rows than within the rows. Analysis of soil samples collected from within corn rows and between rows showed higher atrazine concentration between the corn rows.
Small Grain and Grass Weed Response to BAS-514 with Adjuvants
Authors: Manthey Frank A. , Nalewaja John D. , Szelezniak Edward F.
Published: March 2018

Experiments were conducted in the greenhouse and the field to determine the influence of various oil adjuvants on small grain and grass weed susceptibility to foliarly applied BAS-514 OO H (BAS-514). Barnyardgrass, green foxtail, and yellow foxtail were more susceptible to BAS-514 at 0.56 kg ai ha-1applied with than without an oil adjuvant. Shoot fresh weight reductions of barnyardgrass, green foxtail, and yellow foxtail were greater when BAS-514 at 0.56 kg ha-1was applied with a methylated seed oil than with a petroleum oil adjuvant in the greenhouse. Differences in the effectiveness among oil adjuvants in enhancing BAS-514 phytotoxicity were more evident in greenhouse than in field experiments. Oil adjuvant enhancement of BAS-514 varied with plant species. Oats, hard red spring wheat, and winter wheat tolerated BAS-514 at 1.1 kg ha-1foliarly applied with or without an oil adjuvant in the greenhouse. BAS-514 at 0.56 kg ha-1applied with oil adjuvants caused less than 5% injury to wheat in the field.
Control of Young Mediterranean Saltwort (Salsola vermiculata) with Postemergence Herbicides
Authors: Creager Richard A.
Published: March 2018

Mediterranean saltwort has become an established weed in the upper San Joaquin Valley and the Temblor Range areas of California. Fifteen herbicides were evaluated to determine their effects on 6- to 8-week-old plants grown in the greenhouse. Mediterranean saltwort was killed by chlorsulfuron3, hexazinone, and metribuzin at low rates. Triclopyr4(Garlon 3A and Garlon 4), atrazine, imazapyr, glyphosate, dicamba, bromacil, karbutilate, and simazine were effective at higher rates. Four herbicides, asulam, pendimethalin, amitrole, and fosamine, did not kill Mediterranean saltwort at the rates tested.
Wild-Proso Millet (Panicum miliaceum) Control in Sweet Corn (Zea mays)
Authors: Shenk Myron D. , Braunworth William S. , Fernandez Raquel J. , Curtis Daniel W. , McGrath Daniel , William Ray D.
Published: March 2018

The effects of seed depth on growing point location of wild-proso millet, effects of alachlor placement, and chemical control of wild-proso millet were studied in field and greenhouse experiments. In 1986, 55 to 88% of the seedlings originating in the top 6 cm of soil had their growing point above the soil surface. The respective figures were 11 to 36% in 1987. Shoot exposure to alachlor resulted in significantly greater phytotoxicity than root exposure. Only EPTC or vernolate with a protectant, preplant incorporated, or pendimethalin preemergence, followed by atrazine plus tridiphane postemergence controlled wild-proso millet more than 85% all season.
Effect of Herbicides on Take-All Disease (Gaeumannomyces graminis) in Winter Wheat (Triticum aestivum)
Authors: Geddens Ray M. , Appleby Arnold P. , Powelson Robert L.
Published: March 2018

Experiments were conducted in each of two seasons to determine possible effects of diclofop, difenzoquat, dinoseb, and mecoprop on the incidence of take-all disease and grain yield of winter wheat. All of the herbicides, especially mecoprop, reduced incidence of take-all. Treatments increased grain yields the first year but not the second, compared to the inoculated weed-free control. None of the herbicides tested increased incidence or severity of take-all disease in either of the two seasons. The technique of inoculating disease-free soil was successful in obtaining uniform and reproducible incidence of disease.
The Effects of Selected Herbicides on Musk Thistle (Carduus nutans) Viable Achene Production
Authors: Beck K. George , Wilson Robert G. , Henson M. Ann
Published: March 2018

Chlorsulfuron, metsulfuron, clopyralid, 2,4-D, picloram, and dicamba plus 2,4-D were spring-applied to musk thistle in rosette, bolting, bud, and early flower growth stages. All treatments reduced viable achene production at all musk thistle growth stages at Mcgrew, NE, and Longmont, CO. However, differences occurred at Evergreen, CO, among treatments and growth stages. No achenes developed at Evergreen when herbicides were applied during the rosette stage with dicamba plus 2,4-D, picloram, or metsulfuron at 21 g ai/ha or during bolting with chlorsulfuron or metsulfuron at 21 g/ha. Chlorsulfuron applied during early bloom reduced viable achene production over 99% compared to untreated plants and the picloram treatment.
A Rapid Bioassay to Detect Trifluralin-Resistant Green Foxtail (Setaria viridis)
Authors: Beckie Hugh J. , Friesen Lyle F. , Nawolsky Ken M. , Morrison Ian N.
Published: March 2018

In a petri dish assay, radicle growth of trifluralin-resistant (R) green foxtail exposed to trifluralin concentrations of up to 0.4 ppm (w/v) was not inhibited. Radicle growth of trifluralinsusceptible (S) biotypes was completely inhibited. Shoots were more sensitive to trifluralin than roots, with shoot growth being inhibited for both R and S biotypes at trifluralin concentrations of 0.2 ppm or more. Best discrimination between R and S green foxtail biotypes was achieved by measuring radicle length after incubation of pregerminated caryopses at 0.3 ppm trifluralin in the dark for 5 d at 22 C.
Cultivation and Herbicides for Weed Control in Sweet Potato (Ipomoea batatas)
Authors: Glaze Norman C. , Hall Melvin R.
Published: March 2018

Alachlor, chloramben, cinmethylin, diphenamid, fluazifop, fluazifop-P, metolachlor, metribuzin, napropamide, oryzalin, and sethoxydim were applied on transplanted sweet potato at Tifton, GA, during 1982 to 1985. The weeds most prevalent were large crabgrass, Florida pusley, smallflower morningglory, and yellow nutsedge. No significant phytotoxicity was observed from any herbicide treatment over the 4 yr. Cultivation at 4 wk is advantageous to eliminate early flushes of weeds which escape control and reform the beds. Alachlor or metolachlor at 4.5 and 3.4 kg ha-1, respectively, and metribuzin controlled weeds best. Although no serious phytotoxicity was evident, these treatments tended to cause lowered yields of marketable roots while marginally affecting total yields in most cases. Metribuzin was the only compound which controlled late-season broadleaf weeds such as smallflower morningglory effectively.
Rhizome Bud Viability of Quackgrass (Elytrigia repens) Treated with Glyphosate and Quizalofop
Authors: Tardif François J. , Leroux Gilles D.
Published: March 2018

The effect of the isopropylamine salt of glyphosate and the ethyl ester of quizalofop on the rhizome bud viability of five quackgrass biotypes was tested. Two bioassays used were: direct measure of the growth of the bud on an agar medium and determination of the respiratory activity with tetrazolium chloride. The response to herbicide treatments differed among biotypes. The growth bioassay showed lower viability than the tetrazolium bioassay. Quizalofop reduced viability more than glyphosate. Viability of untreated buds increased with increasing distance from the base of the rhizome. The viability of herbicide-treated buds was more or less equal regardless of the position. It appeared that both herbicides were translocated to all the rhizome buds.
Chlorsulfuron Persistence and Response of Nine Rotational Crops in Alkaline Soils of Southern Alberta
Authors: Moyer James R. , Esau Rudy , Kozub Gerald C.
Published: March 2018

Chlorsulfuron was applied to wheat at rates of 0, 10, 20, and 40 g ai ha-1in three locations at Lethbridge and Brooks between 1980 and 1984. The soil pH and organic matter contents at Lethbridge and Brooks were 8.0 and 2.1% and 7.4 and 3.0%, respectively. Rotational crops were seeded for up to 7 yr after chlorsulfuron application. The criteria used to indicate when susceptible crops will grow safely were no significant yield loss at the 40 g ha-1rate and the magnitude of the upper confidence limit for this difference. The following times after application before crop yields were not affected were required at Lethbridge: barley, 2 yr; canola, 3 yr; peas, beans, 4 yr; flax and potatoes, 5 yr; alfalfa and sugarbeets, 6 yr; and lentils at least 7 yr. The effect of chlorsulfuron residues in the soil on rotational crops appeared to be similar at Brooks and at Lethbridge. Estimated chlorsulfuron concentrations were related to the tolerance of rotational crops.
Effect of Grazing Cheat (Bromus secalinus)-Infested Wheat (Triticum aestivum) on Both Species
Authors: Koscelny Jeffrey A. , Peeper Thomas F.
Published: March 2018

Data from three field experiments were used to determine the effects of grazing cheat-infested winter wheat during tillering on cheat and wheat growth, mature biomass, and wheat grain yield components. When terminated, grazing had reduced wheat leaf area 52% and cheat leaf area by 28%. Pooled over experiments, grazing decreased mature wheat height 7 cm and wheat yield 17%. Grazing increased dockage due primarily to cheat 9%. Grazing effects on wheat yield components, biomass, and cheat panicle density varied. Grazing did not affect cheat tillering or wheat harvest index.
Sodium Bicarbonate Antagonism of 2,4-D Amine
Authors: Nalewaja John D. , Woznica Zenon , Manthey Frank A.
Published: March 2018

2,4-D diethanolamine control of kochia was influenced by the source of water used as the spray carrier. Sodium bicarbonate in one water source related to the reduced kochia control. Sodium bicarbonate in a water spray carrier antagonized 2,4-D control of all plant species evaluated. Antagonism increased with the tolerance of a species to 2,4-D, concentration of sodium bicarbonate, and spray volume. Sodium bicarbonate antagonism of 2,4-D phytotoxicity was greatest with low temperature and relative humidity.
Tolerance of Safflower (Carthamus tinctorius), Corn (Zea mays), and Proso Millet (Panicum miliaceum) to Clomazone
Authors: Anderson Randy L.
Published: March 2018

Clomazone is used in the Central Great Plains for weed control during fallow in a winter wheat-fallow rotation. Improved precipitation storage during non-crop periods has stimulated new crop rotations such as winter wheat-corn or proso millet-fallow. The objective of this study was to determine if clomazone applied in the fall after winter wheat harvest would injure succeeding spring-planted crops. Greenhouse studies indicated crop tolerance to clomazone was in the order of safflower > corn > proso millet > barley > winter wheat. Clomazone did not affect grain yields of safflower, corn, or proso millet grown at two field sites with different soil textures (silt loam and sandy loam), nor germination of seed from treated plants of these crops. A no-till production system with clomazone increased grain yields for all crops compared to the conventional system where tillage replaced clomazone for fallow weed control.
Horseweed (Conyza canadensis) Control in No-Tillage Soybeans (Glycine max) with Preplant and Preemergence Herbicides
Authors: Bruce Joseph A. , Kells James J.
Published: March 2018

Research was conducted in 1987 and 1988 to identify effective horseweed control strategies in no-tillage soybean production. Paraquat at 560 g ai ha-1plus metolachlor at 2200 g ai ha-1, linuron at 840 g ai ha-1, and nonionic surfactant at 0.25% (v/v) applied preemergence provided less than 61% horseweed control. Glyphosate at 840 g ai ha-1, 2,4-D ester at 560 g ai ha-1, HOE-39866 at 840 g ai ha-1, or BAS-514 at 70 g ai ha-1applied early preplant controlled more than 96% when followed by the above preemergence herbicide combination. Substituting either glyphosate at 840 g ha-1or HOE-39866 at 840 g ha-1for paraquat in the preemergence application program significantly increased control. Adding BAS-514 at 70 g ha-1to preemergence treatments containing paraquat significantly improved control. The substitution of metribuzin, metribuzin plus chlorimuron (10:1 ratio), or linuron plus chlorimuron (16:1 ratio) for linuron resulted in greater control and soybean yield. Sequential applications controlled horseweed equal to or better than a single preemergence application at the same total rate.
Herbicide Interactions withColletotrichum gloeosporioidesf. sp.malvaea Bioherbicide for Round-leaved Mallow (Malva pusilla) Control
Authors: Grant Nelson T. , Prusinkiewicz Elizabeth , Mortensen Knud , Makowski Roberte M. D.
Published: March 2018

Colletotrichum gloeosporioidesf. sp.malvae(C.g.m.) was evaluated under greenhouse conditions for round-leaved mallow control in combination with the following herbicides: bromoxynil plus MCPA (1:1), diclofop, imazethapyr, metribuzin, sethoxydim, and 2,4-DB. Treatments consisted of C.g.m. and herbicide applied alone, tank mixed, and C.g.m. applied 48 h before, and 1, 24, and 72 h after herbicide. Split applications with bromoxynil plus MCPA, imazethapyr, metribuzin, (C.g.m. before or after) and sethoxydim (C.g.m. before) enhanced round-leaved mallow control over C.g.m. applied alone. However, diclofop or 2,4-DB tank mixed or applied in a split application with C.g.m. did not improve round-leaved mallow control over C.g.m. applied alone. Bromoxynil plus MCPA, metribuzin, 2,4-DB, and imazethapyr may be tank mixed with C.g.m. without significantly reducing round-leaved mallow control, unlike sethoxydim or diclofop which inhibited C.g.m. development. Dew period did not influence the effectiveness of bromoxynil plus MCPA applied 30 h before C.g.m., but round-leaved mallow control increased with increasing dew period for metribuzin applied 30 h before C.g.m.
Effect of Seeding Depth, Herbicide, and Variety on Sugarbeet (Beta vulgaris) Emergence, Vigor, and Yield
Authors: Wilson Robert G. , Smith John A. , Yonts C. Dean
Published: March 2018

Preplant applied herbicides were compared for their effect on three varieties of sugarbeets when seeds were planted at six depths during 1987 through 1989. More sugarbeet seedlings emerged and at a faster rate as the depth of seeding decreased from 4.5 to 1.6 cm. Herbicide injury to sugarbeet seedlings increased as depth of seeding increased from less than to greater than 2.5 cm. Herbicide treatments reduced sugarbeet stand and decreased early season sugarbeet height but had little effect on root yield or sucrose content.
Cotton (Gossypium hirsutum) Response to Glyphosate Spot Applied
Authors: Westerman R. Brent , Murray Don S.
Published: March 2018

Weed free field experiments were conducted for 3 yr at one location to measure the response of cotton to glyphosate spot applied once, twice, and three times. Glyphosate treatments frequently used for silverleaf nightshade control were applied at specified intervals after cotton emergence to in-row, uniformly spaced densities of “simulated” weeds. The number and application timing influenced cotton injury each year. Frequently, cotton lint yields following treatments applied once at four, six, or eight sites/9 m of row were not reduced significantly compared to the untreated plots; however, average yield reductions ranged from 10 to 14%. Glyphosate, applied more than once generally, caused more crop injury and reduced lint yields by 13 to 39%.
Field Bindweed (Convolvulus arvensis) Control with Imazapyr
Authors: Schoenhals Monty G. , Wiese Allen F. , Wood Mark L.
Published: March 2018

Sixteen applications of imazapyr and other herbicides were made to field bindweed from 1982 to 1986. Control with imazapyr was 89% or more 1 yr after treatment at 0.14 kg ai ha-1when plants were growing vigorously at application. Only 1 of 16 applications of imazapyr at 0.56 kg ha-1controlled less than 90% regardless of plant vigor. Control at 0.56 kg ha-1was usually superior to that obtained with dicamba at 1.1 and 2.2 kg ae ha-1, and 2,4-D at 1.1 kg ae ha-1, as well as combinations of picloram with either 2,4-D or dicamba. All herbicides were less effective when applied to field bindweed with poor vigor. Winter wheat planted in the fall up to 122 days after application was injured 20 to 88% by imazapyr at 0.14 kg ha-1. Sorghum planted the next spring was injured 15% or less by imazapyr at 0.14 and 0.28 kg ha-1.
Ethephon Reduction of Redroot Pigweed (Amaranthus retroflexus) Seed Populations
Authors: Egley Grant H.
Published: March 2018

Freshly collected redroot pigweed seeds were buried 5 cm deep in the field in November of 3 yr in succession. Treatments applied to the soil surface included KNO3(400 kg ha-1) in midwinter, ethephon (11 kg ha-1) in late spring, and a soil cover (polyethylene sheet for 2 wk) in late spring. Seeds were recovered within 1 yr after treatment, examined forin situgermination, and tested for viability. The 3-yr averages for viable seeds remaining by October in the year after treatment with KNO3or soil cover, either alone or in combination, did not differ from nontreated checks and averaged 47% of the original population. Viable seeds remaining in soil treated with ethephon either alone or combined with KNO3 were reduced to 21% of the beginning population. The most effective treatments were ethephon either combined with a soil cover or with a soil cover plus KNO3which reduced the viable seeds to an average of 8% of the original. Ethephon plus a soil cover has the potential to reduce greatly redroot pigweed seed populations in the field.
Lactofen Systems for Broadleaf Weed Control in Peanuts (Arachis hypogaea)
Authors: Wilcut John W. , Swann Charles W. , Hagwood Henry B.
Published: March 2018

Weed management systems using a chloroacetamide herbicide applied preplant incorporated (PPI) and at cracking (AC) plus lactofen applied AC and early postemergence (POST) controlled at least 98% of common lambsquarters. Similar systems using a chloroacetamide herbicide applied PPI and early POST plus lactofen applied early POST and postemergence (POST) controlled less than 70% of common lambsquarters. All sequential lactofen systems controlled common ragweed completely and at least 86% of morningglory species. Highest peanut yields and net returns were obtained with weed management systems consisting of sequential applications of lactofen applied AC and early POST, or systems that used acifluorfen plus bentazon POST, or lactofen plus bentazon applied early POST or POST.
Factors Affecting Chloroacetanilide Injury to Corn (Zea mays)
Authors: Rowe Loston , Penner Donald
Published: March 2018

Greenhouse studies were conducted to determine the effects of herbicide, herbicide rate, genetic variability, and soil moisture content on the tolerance of corn seedlings to two chloroacetanilide herbicides. Alachlor and metolachlor were applied preemergence at 2.2, 3.4, 4.5, and 6.7 kg ha-1to 10 Great Lakes corn hybrids. Metolachlor appeared to be less injurious at the low rate and more injurious at the high rate than alachlor. Injury among the 10 hybrids tested varied significantly. Some of the hybrids appeared to tolerate alachlor more, while others tolerated metolachlor more indicating that even in a limited number of hybrids there was a spectrum of response. Six levels ranging from 8% to 22% soil moisture were evaluated for their effect on alachlor and metolachlor injury to corn seedlings. The herbicide injury ranged from no injury at the lowest soil moisture level to about 70% at the highest soil moisture level with 4.5 kg ha-1application rate of alachlor or metolachlor.
Low Volume Invert Emulsions for Purple Nutsedge (Cyperus rotundus) Control
Authors: Bryson Charles T. , Wills Gene D. , Quimby Paul C.
Published: March 2018

Greenhouse experiments were conducted in 1989 at Stoneville, MS to evaluate the efficacy of fluridone and MSMA applied at 0.3 and 1.0 kg ai ha-1, respectively, either alone or in combination and with or without 0.1 M ammonium sulfate on purple nutsedge. The herbicides were applied at 19 L ha-1in an oil-water, invert emulsion (low-volume) and at 187 L ha-1in water with a nonionic surfactant (0.25% v/v) (high-volume). Purple nutsedge control with both herbicides alone or in combination was greater with the low-volume than with the high-volume application. Addition of MSMA to fluridone, or of ammonium sulfate to fluridone plus MSMA did not enhance purple nutsedge control over fluridone alone applied in low volume. The addition of ammonium sulfate to fluridone alone applied in low volume reduced purple nutsedge control.
Barnyardgrass
Authors: Mitich Larry W.
Published: March 2018

Barnyardgrass [Echinochloa crus-galli(L.) Beauv. ♯3ECHCG], originally from Europe and India, now ranges from latitude 50 N to 40 S, in both temperate and tropical habitats (12). It is a serious weed problem in 42 countries and is found in at least 27 more (11). It is the world's principal weed of rice (12) and likely has been for a long time: barnyardgrass is recognizable in Chinese drawings from 1590 (13).
Satellite Remote Sensing to Predict Potential Distribution of Dyers Woad (Isatis tinctoria)
Authors: Dewey Steven A. , Price Kevin P. , Ramsey Doug
Published: March 2018

Landsat-5 Thematic Mapper spectral data and field survey information were combined to identify specific land cover types associated with 1741 dyers woad infestation points on the Cache National Forest in northern Utah. Ten of 60 possible cover types were strongly associated with current dyers woad infestations, and therefore considered highly suited to establishment and survival of the weed. Non-infested land of the same “highly suited” cover types comprised an additional 24 714 ha within the 149 021-ha study area, suggesting the potential for an eventual 124-fold increase in dyers woad incidence on the forest.
Cotton (Gossypium hirsutum) Response to Simulated Triclopyr Drift
Authors: Snipes Charles E. , Street Joe E. , Mueller Thomas C.
Published: March 2018

Cotton response to triclopyr was evaluated when it was applied over-the-top at simulated drift rates to pin-head square and early bloom cotton growth stages in 1987 and 1988. The herbicidal effects of triclopyr were most evident after a lag period of 10 to 15 d. Triclopyr at 60 g ai ha-1applied at pin-head square reduced cotton height in 1987, but not in 1988. Triclopyr applied at pin-head square and early bloom reduced cotton flowering initially, as measured by white bloom counts, in both years. Total blooms were reduced in 1987, but not in 1988. Cotton maturity was delayed by triclopyr application during early bloom, as shown by a decrease in percent open bolls, and a decrease in first pick cotton yields. Cotton yield was lower in plots receiving triclopyr, with the greatest yield reduction caused by a 60 g ha-1triclopyr application at early bloom.
Effect of Application Factors on Efficacy of Fluazifop-P-Butyl in Flax
Authors: Friesen George H. , Wall David A.
Published: March 2018

Field experiments were conducted to determine the efficacy of fluazifop-P-butyl for the control of green foxtail, wild oat, barley, and wheat in flax as influenced by spray nozzle orientation, time of day, and growth stage. Under drought conditions in 1988, control of wild oat, wheat, and barley with fluazifop-P-butyl was enhanced 75%, 53% and 78%, respectively, when nozzles were oriented to spray forward 45°. Under adequate soil moisture conditions enhancement of control was minimal. Green foxtail control improved when fluazifop-P-butyl was applied from 1700 to 2100 h, but time of day had no effect on control of wild oat, barley, or wheat. Fluazifop-P-butyl effectiveness was reduced when applied 4 d after flax emergence due to late emerging grass seedlings. Green foxtail was the most tolerant to fluazifop-P-butyl, whereas wild oat, wheat, and barley were the most susceptible.
Corn (Zea mays) Injury Following Use of Clomazone, Chlorimuron, Imazaquin, and Imazethapyr
Authors: Curran William S. , Knake Ellery L. , Liebl Rex A.
Published: March 2018

This study examined the response of corn to clomazone, chlorimuron, imazaquin, and imazethapyr the year following their application to soybeans. Herbicides were surface-applied from one-half to three times the labeled application rates. Soybeans were planted the year of application and crop tolerance was evaluated. Corn was planted in rotation the following season. Soybeans were tolerant of all four herbicides. The highest rates of clomazone, chlorimuron, and imazaquin injured the corn early in the season. Imazethapyr did not influence corn growth. Visual estimates of clomazone injury were as high as 39% chlorosis. Seedling dry weight reductions at the highest chlorimuron and imazaquin rates were 32% and 24%, respectively. Although corn was injured by higher rates of clomazone, imazaquin, and chlorimuron at the 3-leaf stage, none of the herbicides significantly reduced grain yield. This study suggests that these herbicides can carry over and injure corn, especially if labeled application rates are exceeded. However, low to moderate early season injury to corn may not affect grain yield.
Injury and Yield Response of Selected Crops to Imazaquin and Norflurazon Residues
Authors: Barnes Clyde J. , Lavy Terry L.
Published: March 2018

Field studies were conducted in 1987, 1988, and 1989 to evaluate the effects of freshly applied residual levels (simulated residue carryover) of imazaquin and norflurazon on the growth and yield of corn, cotton, grain sorghum, rice, and wheat. Studies ware conducted on five soils, and concentrations of herbicides were determined at crop planting. Crop injury ratings were recorded 4 wk after emergence, and yields were measured at the end of each growing season. In simulated residue carryover studies, corn and grain sorghum injury occurred and yields were reduced when norflurazon concentrations were 450 ng g-1soil or greater. Rice yields were reduced at norflurazon concentrations of 710 ng g-1. Corn, cotton, and wheat heights and yields were reduced when imazaquin concentrations were 13 ng g-1, 13 ng g-1, and 45 ng g-1soil, respectively for crops. Comparisons between simulated carryover and actual carryover were made for corn and cotton grown in imazaquin treated fields as well as for corn grown in a norflurazon treated field.
Creeping Wartcress (Coronopus squamatus): A New Weed in Southeastern California
Authors: Bell Carl E.
Published: March 2018

Creeping wartcress was first identified in the Imperial Valley of southeastern California in 1982. From two limited invasions of approximately 2 ha each, by 1987 this weed had infested 1500 ha. Creeping wartcress can behave as an annual or biennial weed and is a member of the mustard family (Brassicaceae). Creeping wartcress seed germinates from September through March and flowers first appear in racemes in late February, continuing through May.
Integrated Weed Management–A Component of Integrated Pest Management: A Critical Review
Authors: Thill Donald C. , Lish Joan M. , Callihan Robert H. , Bechinski Edward J.
Published: March 2018

Integrated weed management (IWM) is a component of integrated pest management (IPM), which is an interdisciplinary practice involving disciplines such as entomology, nematology, plant pathology, weed science, horticulture, agronomy, ecology, economics, and systems science. Most descriptions of IPM mention three elements: a) multiple tactics (for example, competitive varieties, cultural practices, herbicide usage) used in a compatible manner; b) pest populations maintained below levels that cause economic damage, and c) conservation of environmental quality. Integrated weed management was discussed in 1981 during a Weed Science Society of America (WSSA) Symposium entitled Integrated Weed Management Systems Technology for Crop Production and Protection. Topics presented included modeling weed biology, crop manipulation, biological control, herbicide technology, research needs, teaching approaches, and extension implementation. Our paper was presented as part of a symposium on IWM at the 1990 WSSA meeting. This paper describes some of the research that weed scientists have conducted during the past 40 yr. Topics examined include an introductory review of IPM, trends in several categories of weed research, goals and suggestions stated during the 1981 WSSA Symposium on IWM, IWM accomplishments since about 1981, and the future of IWM as a component of IPM.
Size-Dependent Economic Thresholds for Three Broadleaf Weed Species in Soybeans
Authors: Weaver Susan E.
Published: March 2018

Soybean seed yield losses due to interference from common cocklebur, velvetleaf, and jimsonweed, with and without a PPI application of 0.42 kg ai ha-1metribuzin, were determined in 1986, 1987, and 1988. Damage functions were calculated based on weed density, weed leaf density, and relative weed leaf area index, respectively. Functions relating crop yield losses to weed density varied significantly among treatments and years for each species. Weeds which escaped soil-applied metribuzin were shorter with fewer leaves at 3 wk after planting, and caused lower crop yield losses than control plants at equal densities. Yield loss estimates based upon relative weed leaf area at 3 wk after planting showed least variation between years and treatments.
Resistance of Selected Ornamental Grasses to Graminicides
Authors: Catanzaro Christopher J. , Skroch Walter A. , Burton James D.
Published: March 2018

Greenhouse trials were conducted to evaluate graminicidal resistance of selected ornamental grasses. Blue fescue cultivars ‘Blue Glow’, ‘Sea Urchin’, ‘Spring Blue’, and ‘Superba’ were resistant to 1× (medium use rate) and 2× rates of fenoxaprop, fluazifop-P, quizalofop, and sethoxydim, whereas fountain grass, ravenna grass, and switchgrass were sensitive. Minor (<20%) visible phytotoxicity was observed on some fescues treated with the 2× rate of fluazifop-P at 14 but not at 69 days after treatment (DAT). Fountain grass, ravenna grass, and switchgrass exhibited severe (>70%) phytotoxicity from all herbicides 69 DAT. Mortality of non-fescues ranged from 55% (fountain grass) to 96% (ravenna grass).
Soybean (Glycine Max) Tolerance and Sicklepod (Cassia Obtusifolia) Control with AC 263,222
Authors: Griffin James L. , Reynolds Daniel B. , Vidrine P. Roy , Bruff Stacey A.
Published: March 2018

In field studies conducted under weed-free conditions, soybean yield was not adversely affected with POST applications of AC 263,222 at 18 g ha−1. At 36 g ha−1, soybean height at maturity was reduced in three of five studies and soybean yield in two of five studies. Application of 9 g ha−1of AC 263,222 to sicklepod at cotyledon to four-leaf (early POST) or at a maximum size of five-leaf (late POST) provided 30 to 48% control. Control was 54 to 73% with AC 263,222 at 9 g ha−1applied early POST followed by late POST. Regardless of application rate or timing, sicklepod control with AC 263,222 generally was inferior to the standard treatments of pendimethalin plus imazaquin PPI followed by imazaquin late POST or pendimethalin PPI and metribuzin PRE followed by chlorimuron late POST. Compared with the weed-free check, soybean yield was reduced when AC 263,222 was applied at 9 g ha−1early POST followed by late POST in one of two studies and in two of three studies when applied at 18 g ha−1early POST.
Optimizing Adjuvants to Overcome Glyphosate Antagonistic Salts
Authors: Nalewaja John D. , Matysiak Robert
Published: March 2018

Glyphosate toxicity to wheat was antagonized more by calcium chloride than sodium bicarbonate. Mixtures of the salts at greater than 100 mg L−1sodium bicarbonate and 200 mg L−1calcium chloride were additive in antagonism of glyphosate in the greenhouse experiments. Surfactant and oil adjuvants did not overcome sodium bicarbonate or calcium chloride antagonism of glyphosate. Oil adjuvants were generally antagonistic to glyphosate. An equation is presented that determines the amount of diammonium sulfate required to overcome glyphosate antagonism based upon the sodium, potassium, calcium, and magnesium cations in the spray carrier.
Reduced Rates of Postemergence Herbicides in Conventional Soybeans (Glycine max)
Authors: Prostko Eric P. , Meade John A.
Published: March 2018

The efficacy of reduced rates of fomesafen, bentazon plus acifluorfen, and chlorimuron, in combination with sethoxydim was investigated in New Jersey from 1989 to 1991. Herbicides applied at sequential 0.25x rates controlled common lambsquarters, common ragweed, and stinkgrass. Chlorimuron plus sethoxydim did not control common lambsquarters at any rate. Generally, herbicides applied at 0.5x rates were not as effective as the full or sequential 0.25x rates. Yields of plots treated with reduced rates were equal to or greater than those treated with full rates.
Integrating Reduced Herbicide Use with Mechanical Weeding in Corn (Zea mays)
Authors: Mulder Thomas A. , Doll Jerry D.
Published: March 2018

Concern about the effects of pesticides on the environment and the desire to reduce purchased inputs are stimuli to reduce herbicide use. Field research was conducted at two locations for two growing seasons to identify integrated weed management practices in corn that are effective and economical. Weed control treatments included PRE application of a herbicide mixture of 1.8 kg ai ha−1of atrazine plus 2.2 kg ai ha−1of metolachlor alone, this mixture broadcast or band-applied at a reduced rate in combination with mechanical weeding, and mechanical weeding alone. Weed control, corn yield, and economic returns were generally higher in treatments combining herbicides and mechanical weeding than those using only mechanical measures. Without herbicides, timeliness of rotary hoeing was critical. Herbicide use can be reduced 50 to 75% in integrated systems with minimal risk of yield loss due to uncontrolled weeds.
Immunoassay to Detect Enhanced Carbamothioate Degradation in Soil
Authors: Hutchinson Pamela J. , Shea Patrick J. , Takacs James M. , Staswick Paul E.
Published: March 2018

An indirect enzyme-linked immunosorbent assay (ELISA) for EPTC was developed that may be useful for predicting enhanced carbamothioate herbicide degradation in adapted soils. A modified radioimmunoassay (RIA) procedure was used to detect antibodies specific for EPTC and establish antibody dilutions for optimum ELISA sensitivity. Antibodies were obtained from a rabbit injected with a butylate-analog protein conjugate. An indirect ELISA subsequently was developed for EPTC with a detection range of 10 to 1280 ng ml−1 in a 1:3 aqueous dilution of a 90:10 (v/v) acetonitrile (ACN):water soil extract. EPTC recovery from soil was > 96%, as determined by conventional gas chromatography. Measurement of low concentrations of residual EPTC with the ELISA was less quantitative than by gas chromatography, but the immunoassay provided a rapid, potentially cost-effective method for screening soils to determine enhanced carbamothioate degradation.
Improving Weed Control with 2,4-DB Amine in Seedling Alfalfa (Medicago Sativa)
Authors: Cudney David W. , Orloff Steve B. , Adams Carol J.
Published: March 2018

2,4-DB ester had been widely used for winter annual broadleaf weed control in seedling alfalfa in the western United States, but was replaced commercially by the amine formulation in 1990. Field studies conducted in the high desert region of southern California confirmed previous reports that 2,4-DB amine is not as effective as the ester formulation. Two methods were found to improve the weed control performance of 2,4-DB amine: 1) application at earlier alfalfa growth stages and 2) the addition of adjuvant. Applications made at the three-trifoliate leaf stage of the alfalfa were more than three times as effective as applications made at the eight-trifoliate leaf stage. When adjuvants were added to the amine formulation, weed control was improved 50 to 97%.
Postemergence Control of Cowpea (Vigna unguiculata) in Cotton (Gossypium hirsutum)
Authors: Stapleton Gregory S. , Murdock Edward C. , Toler Joe E.
Published: March 2018

POST control of cowpea in cotton was evaluated in 1990 and 1991. Early POST-directed (EPD) application of fluometuron + MSMA provided 89% cowpea control 2 wk after treatment. Cowpea control 4 wk after the early treatments was similar with fluometuron + MSMA EPD and sequential directed applications of MSMA followed by (fb) MSMA, methazole + MSMA fb cyanazine + MSMA, and fluometuron + MSMA fb cyanazine + MSMA. The average reduction in cowpea biomass 12 wk after planting with these treatments was 93%. MSMA fb MSMA POST-directed was the only treatment with a lint cotton yield similar to that of weed-free cotton. Lint cotton yields with fluometuron + MSMA, methazole + MSMA fb cyanazine + MSMA, and fluometuron + MSMA fb cyanazine + MSMA were similar to those obtained with MSMA fb MSMA.
Effects of Paraquat on Weed Control and Yield of Alfalfa (Medicago sativa) in Virginia
Authors: Foy Chester L. , Witt Harold L.
Published: March 2018

Field experiments were conducted during 1981 to 1984 to evaluate paraquat for weed control in alfalfa established for less than one year. Treatments were applied in March to alfalfa up to 4 cm tall and/or after cuttings to alfalfa up to 10 cm tall. Weeds were up to 20 cm tall. Paraquat applied in March controlled common chickweed and shepherd's-purse in some experiments. It did not control birdsrape mustard when applied after cuttings. Paraquat suppressed growth of perennial broadleaf weeds and grasses and reduced pressure from annual grasses in some experiments. March treatments generally did not increase, but sometimes decreased alfalfa yields. Paraquat applied after cuttings did not affect alfalfa yields in the majority of the experiments.
Interference of Wild Poinsettia (Euphorbia heterophylla) with Soybean (Glycine max)
Authors: Willard Teresa S. , Griffin James L. , Reynolds Daniel B. , Saxton Arnold M.
Published: March 2018

Field-studies were conducted over two years to determine the area of influence and duration of interference of wild poinsettia in soybean. Soybean canopy width averaged across years was reduced approximately 10% beginning at 6 wk of interference for both the 0- to 10-and 10-to 20-cm distances from the weed. Soybean dry weights decreased from 14 to 38% within 20 cm of the weed for 12 through 18 wk of interference. In 1990, soybean yield within 10 cm of wild poinsettia was similar to distances of 10 to 20 and 20 to 40 cm, but was less than that for distances greater than 40 cm from the weed. Weed interference resulted in a 9.5% yield reduction in the 0- to 10-cm distance when compared with the 80-to 100-cm distance. In contrast, yield of soybean in 1991 growing within 10 cm of the weed was less than at greater distances, corresponding to an 18% yield reduction when compared with 80 to 100 cm. Differences in wild poinsettia dry weights when growing alone and when growing within the soybean row occurred after 6 and 8 wk of interference in 1990 and 1991, respectively. In 1991 when rainfall during the growing season was twice that of the previous year, canopy width and dry weight of wild poinsettia growing within the soybean row were reduced an average of 57 and 82%, respectively, compared with weeds growing alone.
Phytotoxicity of Endothall on Peanut (Arachis hypogaea): Formulation, Rate, and Time of Application
Authors: Johnson W. Carroll , Colvin Daniel L. , Mullinix Benjamin G.
Published: March 2018

Field studies were conducted at Tifton, GA and Gainesville, FL to quantify the phytotoxicity of endothall formulation, rate, and time of application on peanut in a weed-free experiment. Peanut treated with mono (N,N-dimethylalkylamine) salt of endothall (DMAA endothall) were more necrotic than those treated with dipotassium salt of endothall (DP endothall), though necrosis was temporary. Injury from DMAA endothall at rates of 0.6 to 1.1 kg ai/ha was similar to the standard treatment of bentazon plus paraquat for most parameters. Peanut treated with the highest rate of DMAA endothall (4.5 kg/ha) were more necrotic and took longer to recover than lower rates. The highest rate of DP endothall (4.5 kg ai/ha) stunted peanut more than any DMAA endothall treatment. However, lower rates of DP endothall (0.6 to 2.2 kg/ha) were generally less injurious than DMAA endothall at equivalent rates. Peanut yields were not affected by either formulation of endothall at 0.6 to 1.1 kg/ha, applied from vegetative emergence through 4 wk after emergence.
Kochia (Kochia scoparia) and Green Foxtail (Setaria viridis) Interference in Sugarbeets (Beta vulgaris)
Authors: Mesbah Abdelouhab , Miller Stephen D. , Fornstrom K. James , Legg David E.
Published: March 2018

Two field experiments were conducted between 1990 and 1992 under sprinkler irrigation at the Research and Extension Center, Torrington, WY to determine the influence of mixed densities and durations of kochia and green foxtail interference in sugarbeet. Sugarbeet root yield and top weight generally decreased as densities of green foxtail and kochia increased whether alone or in combination. Reductions in sugarbeet root yield and above ground biomass from mixed densities of kochia and green foxtail were additive at the low and intermediate density but less than additive at the high density of either species. Sugarbeet root yield decreased as the duration of interference after sugarbeet emergence from a mixed density of kochia and green foxtail increased. Since sugarbeet plants were irrigated to avoid water stress and adequate nutrients were applied, it appears that kochia and green foxtail interfered with sugarbeet primarily for light, based on light and height measurements. Season-long as well as duration of interference did not show any significant effect on sucrose content. Based on regression analysis the lowest densities of kochia and green foxtail required to reduce root yield were approximately 0.3 and 0.06 plants/m of row, respectively. The minimum duration of time that 0.5 kochia and 3.0 green foxtail plants/m of row can interfere with sugarbeets before root yield is economically reduced was approximately 3.5 wk after sugarbeet emergence.
Control of Ivyleaf Morningglory (Ipomoea hederacea) in Cotton (Gossypium hirsutum) by Combinations of Methods
Authors: Thullen Robert J. , Keeley Paul E.
Published: March 2018

Various combinations of methods were evaluated for the control of ivyleaf morningglory growing in cotton. The combinations included chemicals incorporated to two depths or tanked-mixed as postemergence treatments and cultural methods that included in-row cultivation and hand weeding. The most effective combinations of methods included a herbicide such as cyanazine or prometryn in some treatments resulting in reduced ivyleaf morningglory population and improved cotton yields. Cultural methods without chemical assistance gave little or no control of ivyleaf morningglory based on weed populations and cotton yield. Statistically the best combinations had lint yields equal to the weed-free treatment, but the yields were reduced from 114 to 372 kg/ha. Also, most combination treatments had enough plant debris in the lint to reduce fiber grade.