bluuebunny/crossref_metadata_2025 huggingface dataset:
Control of Honey Mesquite (Prosopis julifloravar.glandulosa) and Macartney Rose (Rosa bracteata) with Soil-Applied Herbicides
Authors: Meyer R. E. , Bovey R. W.
Published: May 2019

Seven herbicides were applied to the soil surface or subsurface for control of honey mesquite [Prosopis juliflora(Swartz) DC. var.glandulosa(Torr.) Cockerell] and Macartney rose (Rosa bracteataWendl.). Liquid formulations were applied in bands about 1 cm wide, 1.2 m or more apart, and granule or sphere formulations were applied on the soil surface either broadcast or in rows 1.2 m or more apart. On honey mesquite, karbutilate [tert-butylcarbamic acid ester with 3(m-hydroxy-phenyl)-1,1-dimethylurea] and tebuthiuron {N-[5-(1,1-dimethyl)-1,3,4-thiadiazol-2-yl]-N,N′-dimethylurea} were the most effective herbicides with subsurface spray injections being generally more effective than surface applications. On honey mesquite, differences among row spacing treatments with liquid, granule, or sphere formulations of karbutilate were generally either small or insignificant. Roller chopping reduced the honey mesquite canopy but did not influence the percentage of plants killed by karbutilate at rates of 4.5 kg/ha and below. Bromacil (5-bromo-3-sec-butyl-6-methyluracil), diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea], picloram (4-amino-3,5,6-trichloropicolinic acid), prometon [2,4-bis(isopropylamino)-6-methoxy-s-triazine], and 2,3,6-TBA (2,3,6-trichlorobenzoic acid) generally were ineffective as soil treatments for controlling honey mesquite. Of all the herbicides evaluated on Macartney rose, only picloram at 4.5 kg/ha and tebuthiuron at 2.2 and 4.5 kg/ha, as soil treatments, killed a significant number of plants.
Plant Water Stress of Soybean (Glycine max) and Common Cocklebur (Xanthium pensylvanicum): A Comparison Under field Conditions
Authors: Scott H. D. , Geddes R. D.
Published: May 2019

The study was conducted to determine the seasonal and diurnal water stress of soybeans [Glycine max (L.) Merr. ‘Lee 74′] grown under intraspecific competition (competition between plants of the same species) and interspecific competition (competition between plants of different species) with common cocklebur (Xanthium pensylvanicum Wallr.). Midday xylem potentials decreased as the season progressed and were lower in common cocklebur during vegetative growth of soybean and in soybean during reproductive growth. For a given species differences in xylem potential due to mode of competition were small. In the diurnal studies xylem potential for each species decreased to a minimum in the early afternoon but recovered to the original pre-dawn values at night. As the season progressed leaf xylem potential (a) decreased at a greater rate, (b) decreased sooner in the day, and (c) recovered at a slower rate. It was shown that differences in xylem potential between soybean and common cocklebur on a given day were small. Greater diffusive resistance values generally were found with soybean than with common cocklebur and with each species grown under interspecific competition.
Germination and Emergence of Hemp Sesbania (Sesbania exaltata)
Authors: Johnston S. K. , Walker R. H. , Murray D. S.
Published: May 2019

Hemp sesbania [Sesbania exaltata(Raf.) Cory] was more tolerant to induced moisture stress than soybean [Glycine max(L.) Merr.] with osmotic potentials of −4 and −2 bars, respectively, required to reduce germination. Hemp sesbania germinated at temperatures of 15 to 40 C with optimum germination occurring at 30 to 40 40 C. Seed dormancy was caused by impermeable seed coats. Acid scarification of 45 and 60 min and mechanical scarification 20 and 30 s gave maximum germination. Scarification increased water absorption. Light had no effect on germination. As oxygen content increased from 0 to 21%, germination of unscarified seed increased from 5 to 39%, but germination did not increase as oxygen increased from 21 to 100%. Hemp sesbania and soybean emerged from depths up to 12 cm with maximum emergence occurring at the 1- and 3-cm depths. Hemp sesbania emerged faster and in greater numbers at all depths than soybean.
Determination and Characterization of the Effects of Fluometuron and MSMA onChlorella
Authors: Blythe T. O. , Grooms S. M. , Frans R. E.
Published: May 2019

Studies were conducted on the effects of fluometuron [1,1-dimethyl-3-(α,α,α-trifluoro-m-tolyl)urea] on autotrophic growth (no sugar), heterotrophic growth (with sugar), and oxygen evolution and uptake and on the effects of MSMA (monosodium methanearsonate) on autotrophic growth and oxygen evolution and uptake by the unicellular green algaChlorella pyrenoidosaEmerson strain (University of Texas). Two methods of analysis (probit and kinetic) were used to characterize the dosage-response ofChlorellato these herbicides. All measurements ofChlorellaresponse to fluometuron were satisfactorily characterized by probit analysis, but only autotrophic cell number was adequately characterized by kinetic analysis. The fluometuron concentrations giving 50% inhibition on the probit plot were as follows: autotrophic cell number, 2.4 × 10−6M; chlorophyll at 400 nm, 3.3 × 10−6M; heterotrophic cell number, 2.4 × 10−6M; oxygen evolution, 20 × 10−6M. The response of the alga to MSMA was stimulatory instead of inhibitory. Since this stimulation did not consistently range between 10 and 90% of the control, it was not possible to characterize the MSMA dosage-Chlorellaresponse using either type of analysis.
Effects of Atrazine, Cyanazine, and Procyazine on the Photochemical Reactions of Isolated Chloroplasts
Authors: Brewer P. E. , Arntzen C. J. , Slife F. W.
Published: May 2019

The effects of atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine], cyanazine {2-[[4-chloro-6-(ethylamino)-s-triazin-2-yl] amino]-2-methylpropionitrile}, and procyazine {2-[[4-chloro-6-(cyclopropylamino)-1,3,5-triazine-2-yl] amino]-2-methylpropanenitrile} on the photochemical reactions of isolated pea (Pisum sativum L. ‘Progress #9 Dwarf’) chloroplasts were studied. Atrazine, cyanazine, and procyazine inhibited electron transport but did not uncouple photophosphorylation. The primary site of inhibition for all three herbicides was on the reducing side of photosystem II; the electron transfer step between the primary electron acceptor (Q) and the plastoquinone pool of the electron transport chain is suggested as the site of action of all three herbicides. The amount of inhibition of electron transport observed after addition of herbicide to isolated chloroplasts was time-dependent for cyanazine and procyazine but not for atrazine. This was apparently due to a slower partitioning of cyanazine and procyazine from the aqueous phase of the reaction solution into the highly hydrophobic environment within the chloroplast membrane. Treatment of the thylakoid membranes with detergent reduced the time-dependent inhibitory nature of cyanazine and procyazine, and the ability of atrazine to block electron transport. A photosystem II-dependent electron transport assay and a chlorophyll fluorescence induction assay were used to determine the inhibitory potentials of atrazine, cyanazine, and procyazine. After allowing for differences in the rate of membrane penetration, I50 values of approximately 2 × 10−7 M were determined for each of the three herbicides.
Soil Detection and Mobility of Fluridone
Authors: Banks P. A. , Merkle M. G.
Published: May 2019

Bioassay and gas chromatographic procedures were evaluated for their effectiveness in detecting fluridone [1-methyl-3-phenyl-5-[3-(trifluoromethyl)phenyl]-4(1H)-pyridinone] in soil. Bioassay procedures were limited to a detection range of 0.05 to 0.45 ppmw if grain sorghum (Sorghum bicolor(L.) Monech) was used. Visual estimations of chlorophyll content in affected plants, used as an indicator of fluridone concentration, were as reliable as spectrophotometric determinations. Gas-liquid chromatographic (GLC) procedures were less variable than the bioassay and had no upper limit of detection. Recovery of fluridone from treated soil ranged from 60 to 100 percent, depending on soil type. Soil water content affected percent recovery. Fluridone did not leach more than 1 cm in clay or sandy loam soils when up to 10 cm of water was passed through a soil column containing the herbicide, as determined by GLC. Extensive downward movement, 12 to 16 cm, occurred in a coarse sand when 5 or 10 cm of water was passed through the column.
Efficacy and Rotational Crop Response to Levels and Dates of Dinitroaniline Herbicide Applications
Authors: Abernathy J. R. , Keeling J. W.
Published: May 2019

Trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine), dinitramine (N4,N4-diethyl-α,α,α-rifluoro-3,5-dinitrotoluene-2,4-diamine), profluralin [N-(cyclopropylmethyl)-α,α,α-trifluoro 2,6-dinitro-N-propyl-p-toluidine], fluchloralin [N-(2-chloroethyl)-2,6-dinitro-N-propyl-4-(trifluoromethyl)aniline], pendimethalin [N-(1-ethylpropyl)-3,4-dimethyl-2,6-dinitrobenzenamine], butralin [4-(1,1-dimethylethyl)-N-(1-methylpropyl)-2,6-dinitrobenzenamine], and USB 3153 (N3,N3-di-N-propyl-2,4-dinitro-6-trifluoromethyl-m-phenylenediamine) were applied to evaluate weed control, cotton (Gossypium hirsutumL. ‘Dunn 119′) tolerance, and effect on rotational crops. Each herbicide was applied at 1-month intervals for 6 months prior to planting at 1, 1.25, 1.5, and 2X the recommended rates. Pigweed (Amaranthus hybridusL. andA. retroflexusL.) population counts and visual control ratings showed that weed control improved when treatments were applied closer to planting. Applications in November and December at 1.25X profluralin, 1.5X trifluralin, fluchloralin, and pendimethalin, 1X USB 3153, and 2X butralin were required to give effective weed control. Spring applications of 1X rates of profluralin, trifluralin, fluchloralin, and USB 3153, 1.25X rates of pendimethalin and dinitramine and 1.5X rate of butralin were required for adequate weed control. USB 3153 at all rates and dates of application severely limited growth and yields of wheat (Triticum aestivumL. ‘Funk 332′) planted after harvest and also the following May. Spring applications of profluralin at 1.5 and 2X rates and trifluralin at the 2X rate resulted in significant injury of rotational sorghum [Sorghum bicolor(L.) Moench ‘Dekalb E-59+’].
Influence of Site of Uptake of Fluridone on Early Development of Soybean (Glycine max) and Cotton (Gossypium hirsutum)
Authors: Rafii Z. E. , Ashton F. M.
Published: May 2019

The double pot technique was used to study the effects of uptake site of fluridone {1-methyl-3-phenyl-5-[3-(trifluoromethyl—phenyl]-4(1H)-pyridinone} on early shoot and root development of soybean [Glycine max(L.) Merr. ‘Williams’] and cotton (Gossypium hirsutumL. ‘Acala SJ-1′). Soybean is susceptible and cotton is resistant to fluridone. Root uptake in soybean resulted in increased shoot length in the epicotyl and shoot apex, reduced shoot fresh weight, chlorosis of primary and trifoliolate leaves, as well as reduced root length, branching, and fresh weight. Shoot uptake resulted in reduced shoot length above the hypocotyl, reduced shoot weight, severe chlorosis of primary leaves, and inhibition of trifoliolate leaf formation. The reduction in the root length, branching, and weight was less by shoot uptake than by root uptake. In cotton, root uptake resulted in reduced shoot length in the epicotyl and shoot apex, slight reduction in shoot weight, no effect on chlorosis of cotyledon leaves, moderate to slight chlorosis of the true leaves, and no effect on root length, branching, or fresh weight. Shoot uptake resulted in reduced length of all shoot components and shoot weight, chlorosis of cotyledon leaves and the true leaves, and reduced root length, branching, and weight. Compared to soybean, cotton required much higher fluridone concentrations to show the above effects. It was generally concluded that in soybean, uptake by both the root and the shoot contributed significantly to the injury, whereas in cotton, shoot uptake was relatively more important.
Germination Characteristics of Italian Thistle (Carduus pycnocephalus) and Slenderflower Thistle (Carduus tenuiflorus)
Authors: Evans Raymond A. , Young James A. , Hawkes Robert
Published: May 2019

Seed germination of Italian thistle (Carduus pycnocephalusL.) and slenderflower thistle (Carduus tenuiflorusCurt.) was rapid and high, with no strong requirements for afterripening. Both species germinated at a wide range of alternating temperatures from −2 to 40 C. Their germination-temperature profiles were similar, with Italian thistle germinating over a slightly wider range of temperatures. The achenes of both species have abundant mucilage. This mucilage, by improving water retention, tended to increase germination on the surface of clay soil.
Growth Inhibition of Cotton (Gossypium hirsutum) and Soybean (Glycine max) Roots and Shoots by Three Dinitroaniline Herbicides
Authors: Murray D. S. , Street J. E. , Soteres J. K. , Buchanan G. A.
Published: May 2019

Environmental control chamber experiments showed that cotton (Gossypium hirsutumL. ‘Stoneville 213′) and soybean [Glycine max(L.) Merr. ‘Bragg’] root and shoot growth were reduced when treated with increasing rates of dinitramine (N4,N4-diethyl-α,α,α-tri-fluoro-3,5-dinitrotoluene-2,4-diamine), profluralin [N-(cyclopropylmethyl)-α,αα-trifluoro-2,6-dinitro-N-propyl-p-toluidine], and trifluralin (α,α,α-trifluoro-2,6-dintrio-N,N-dipropyl-p-toluidine). Viusal root ratings, dry root weights, and fresh and dry herbage weights were used to evaluate plant response to herbicide treatments in environmental chambers. The order of increasing GR50values for cotton on two soils and with all response measurements, except dry root weights on one soil, was trifluralin, dinitramine, and profluralin. The order of increasing GR50values for soybeans on two soils and with all response measurements was dinitramine, trifluralin, and profluralin.
Herbicides for Renovation of Pastures and Control of Tall Ironweed (Vernonia altissima)
Authors: Peters E. J. , Lowance S. A.
Published: May 2019

August and October applications of glyphosate [N-(phosphonomethyl)glycine] and paraquat (1,1′-dimethyl-4,4′-bipyridinium ion) were compared at two rates for pasture renovation. During the 2 yr of the experiment, sod suppression was frequently greater with October applications than with August applications. Medium red clover (Trifolium pratense L.) became established in all the plots, and density and yield tended to increase as grass suppression increased.

Glyphosate was compared over a 3-yr period with an ester of 2,4-D [(2,4-dichlorophenoxy)acetic acid] and picloram (4-amino-3,5,6-trichloropicolinic acid) for control of tall ironweed (Vernonia altissima Nutt.) when applied in August. Picloram killed from about 80 to 100% of the tall ironweed plants and was superior to 2,4-D. Glyphosate was inconsistent for controlling tall ironweed but could be used for killing perennial weeds as well as sod suppression.
Smutgrass (Sporobolus poiretii) Control in Pastures with Herbicides
Authors: Meyer R. E. , Baur J. R.
Published: May 2019

Smutgrass [Sporobolus poiretii(R. & S.) Hitchc.] in native grass and ‘Coastal’ bermudagrass [Cynodon dactylon(L.) Pers.] pastures near Caldwell, Texas, was sprayed with herbicides in 1975 and 1976. Atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] at 4.5 kg/ha; dalapon (2,2-dichloropropionic acid) at 5.6 kg/ha; glyphosate [N-(phosphonomethyl)glycine] at 0.6 and 2.2 kg/ha; and bromacil (5-bromo-3-sec-butyl-6-methyluracil), tebuthiuron {N-[5-(1,1-dimethylethyl)-1,3,4-thiadiazol-2-yl]-N,N′-dimethylurea}, and hexazinone [3-cyclohexyl-6-(dimethylamino)-1-methyl-1,3,5-triazine-2,4(1H,3H)-dione] at 1.1 and 2.2 kg/ha reduced smutgrass foliar cover, particularly if applied from July to November. Dalapon, tebuthiuron, and hexazinone were the most effective herbicides for reducing smutgrass foliar cover. Other grasses generally replaced smutgrass controlled with hexazinone or tebuthiuron, while broadleaf species mostly replaced smutgrass in plots controlled with dalapon or glyphosate. Dalapon, glyphosate, bromacil, hexazinone, and tebuthiuron caused some injury to Coastal bermudagrass for 3 or 4 months following treatment. By fall of the year after treatment Coastal bermudagrass cover in treated plots was equal to or greater than that in untreated plots.
Effectiveness of Herbicide Programs for Annual Bluegrass (Poa annua) Control in Bermudagrass (Cynodon dactylon)
Authors: Bingham S. W. , Shaver R. L.
Published: May 2019

Annual bluegrass (Poa annuaL.) growing in bermudagrass completes its life cycle in May and dies leaving open spaces in the turfgrass. This occurs at a time when summer annual weeds are germinating and these weeds fill the space formerly occupied by the annual bluegrass. As the summer annual weeds die in the fall, annual bluegrass germinates and fills the space formerly occupied by the summer annual weeds. To control annual bluegrass, it is important to control the summer annual grasses and manage the bermudagrass [Cynodon dactylon(L.) Pers.] to maintain a competitive groundcover especially during the peak germination period for the weeds. Herbicide programs over a three-year period were designed to control annual grasses with treatments in April for large crabgrass [Digitaria sanguinalis(L.) Scop.], in May or June for goosegrass [Eleusine indica(L.) Gaertn.] and in late August for annual bluegrass. Oxadiazon [2-tert-butyl-4-(2,4-dichloro-5-isopropoxyphenyl)-δ2-1,3,4-ozadiazolin-5-one] applied in August gave complete control of annual bluegrass. Although oxadiazon has a long residual life in the soil, annual bluegrass was poorly controlled with treatments made in June. Fall (August or September) applications of benefin [N-butyl-N-ethyl-α,α,α-trifluoro-2,6-dinitro-p-toluidine], prosulfalinN-[[4-(dipropylamino)-3,5-dinitrophenyl] sulfonyl]-S,S-dimethylsulfilimine and butralin [4-(1,1-dimethylethyl-N-(1-methylpropyl)-2,6-dinitrobenzenamine] provided adequate control of annual bluegrass with only a few exceptions during the three-year period. Bensulide [O,O-diisopropyl phosphorodithioateS-ester withN-(2-mercaptoethyl)benzenesulfonamide] gave variable control of annual bluegrass; however, this was improved in programs with oxadiazon which provide goosegrass control during summer. In these studies, DCPA [dimethyl tetrachloroterephthalate], even with three applications a year, gave very little control of annual bluegrass. When oxadiazon was used in rotation with DCPA, adequate control was obtained.
Vapor Absorption and Translocation of Dinitroaniline Herbicides in Oats (Avena sativa) and Peas (Pisum sativum)
Authors: Jacques G. L. , Harvey R. G.
Published: May 2019

Roots or shoots of oats (Avena sativaL. ‘Dal’) and peas (Pisum sativumL. ‘Early Perfection’) were exposed to vapors of14C-labeled benefin (N-butyl-N-ethyl-α,α,α-trifluoro-2,6-dinitro-p-toluidine), dinitramine (N4,N4-diethyl-α,α,α-trifluoro-3,5-dinitrotoluene-2,4-diamine), fluchloralin [N-(2-chloroethyl)-2,6 dinitro-N-propyl-4-(trifluoromethyl)aniline], oryzalin (3,5-dinitro-N4,N4-dipropylsulfanilamide), profluralin [N-(cyclopropylmethyl)-α,α,α-trifluoro-2,6-dinitro-N-propyl-p-toluidine], and trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine). All of the dinitroaniline herbicides except oryzalin were absorbed by roots and shoots of germinating oats and peas. Some root-shoot translocation of the herbicides was observed in peas, but no shoot-root transport could be detected in either peas or oats. In peas,14C from root-absorbed benefin, fluchloralin, profluralin and trifluralin was detected in shoots, and14C from benefin and trifluralin was detected in cotyledons. In general, vapor absorption was correlated with rates of herbicide volatilization.
Analysis of Nonstructural Carbohydrates in Redroot Pigweed (Amaranthus retroflexus) and Robust Foxtail (Setaria viridisvar.robusta) Throughout the Growing Season
Authors: Orwick P. L. , Schreiber M. M.
Published: May 2019

Redroot pigweed (Amaranthus retroflexusL.) and robust foxtail [Setaria viridis(L.) Beauv. var.robusta-albaSchreiber orSetaria viridisvar.robusta-purpureaSchreiber] were investigated to measure the accumulation of nonstructural carbohydrates throughout two separate growing seasons. Pigweed tended to accumulate more total nonstructural carbohydrates (TNC) than foxtail, particularly in the roots. In both weeds, peak levels of TNC in leaves, stems, and roots occurred during early flowering. The primary nonstructural carbohydrate in the leaves of both weeds was starch. Reducing sugars were the predominant nonstructural carbohydrate in the stems. Starch accumulated more in the leaves of the upper third of the plant and reducing sugars occurred in the greatest quantity in the middle strata of the stem. Accumulation levels of TNC in the plant organs suggested that the stem was a major sink during the vegetative growth phases of both pigweed and foxtail.
Morphological Development and Germination of Dwarf Spikerush (Eleocharis coloradoensis)
Authors: Yeo Richard R.
Published: May 2019

Dwarf spikerush [Eleocharis coloradoensis(Britt.) Gilly] is an aquatic plant that will displace waterweeds. It was studied to obtain information that will help to manage unwanted vegetation in natural aquatic situations. The morphology of seed and tubers was examined at the light- and scanning-electron microscope levels. Inflorescences were found to bear 3 to 12 florets that matured acropetally. The pericarp was made up largely of rows of annulated cells covered with a water-soluble, waxlike substance that leached away when stored in water at 4 to 6 C. The seed coat consisted of three layers. Each layer contained lipids, giving evidence that they were composed of cutin. When the seed germinated, the cotyledonary sheath emerged first, followed by the culms. Tubers formed and matured in about 30 days. The shoot apices of tubers each had two buds that were protected by five to seven overlapping membraneous leaf scales. When tubers sprouted the longest bud grew first. The second bud contained the culm meristem.
Glyphosate and Paraquat for Interrow Weeding of Strawberries (Fragaria × ananassa)
Authors: Frank J. R. , King J. A.
Published: May 2019

Strawberries (Fragaria X ananassa Duch. ‘Midway’) were grown in the field with and without the use of black plastic mulch. One to three postplant applications of glyphosate [N-(phosphonomethyl)-glycine] at 2.2, 4.5, and 5.6 kg/ha or paraquat (1,1′-dimethyl-4,4′-bipyridinium ion) at 0.6, 1.1, and 2.2 kg/ha were made as directed sprays between the rows in 1976 and 1977. Glyphosate was generally more effective than paraquat for controlling weeds during the entire growing season, although both gave adequate short-term control. When late-season applications were made during 1976, a residual weed control effect was observed from both herbicides during early 1977. Crop yield, fruit size, and fruit quality were not affected by either herbicide. Similar results were obtained in a separate experiment in which strawberries were grown utilizing plastic mulch.
Oxadiazon for Weed Control in Woody Ornamentals
Authors: Bailey Richard E. , Simmons James A.
Published: May 2019

Weed competition in the commercial production of woody ornamentals results in substantial economic losses annually due to increased labor costs and reductions in plant growth and quality. Container and field experiments were established in 1975 and continued through 1976 to evaluate oxadiazon [2-tert-butyl-4-(2,4-dichloro-5-isopropoxyphenyl)-δ2-1,3,4-oxadiazolin-5-one] as a weed control agent and to determine its effect on ornamentals at selected test sites throughout the United States. Test programs were conducted with container and field grown ornamentals at 10 locations during 1975 and subsequently increased to 12 locations in 1976. Rates evaluated included 3.4, 4.5, 5.6 and 11.2 kg/ha. Highly effective control of 17 weeds was obtained for 3-month periods at rates as low as 4.5 kg/ha. Oxadiazon gave commercially acceptable control of common groundsel (Senecio vulgarisL.), a very serious weed problem in containers. Control of common chickweed [Stellaria media(L.) Cyrillo], however, was poor at all rates tested. Ornamental tolerance to oxadiazon was generally excellent. Of the 50 ornamental species evaluated in 1975, only two displayed phytotoxic symptoms; scarlet firethorn (Pyracantha coccineaRoem.) and Chinese privet (Ligustrum sinenseLour.) at 5.6 and 11.2 kg/ha following three successive applications at 3-month intervals. In 1976 trials on 63 species, phytotoxic symptoms could not be reproduced on the above species; chemical intolerance was limited to growth inhibition of aloe yucca (Yucca aloifoliaL.) at 5.6 and 11.2 kg/ha.
Rhythmic Leaf Movements of Some Common Weeds
Authors: Andersen Robert N. , Koukkari Willard L.
Published: May 2019

In growth chamber studies, we measured the movement of cotyledons and leaves or leaflets in seedlings of nine weed species to determine: the magnitude of movement, whether movements followed a rhythmic pattern, and if rhythmic movements were endogenously controlled. Seedlings were always entrained under a 15-h light:9-h dark regime. Measurements were made at 3-h intervals for 3 to 4 days under four light regimes: alternating 15-h light:9-h dark; continuous light; one 15-h light:9-h dark span, followed by continuous light; and a 15-h light:9-h dark regime, in which the dark span was advanced 9 h (phase shift) when measurements were begun. No clearly defined pattern of leaf movement was found in wild mustard [Brassica kaber(DC.) L. C. Wheeler var.pinnatifida(Stokes) L. C. Wheeler]. Daily rhythmic leaf movements that did not appear to be endogenously controlled were found in redroot pigweed (Amaranthus retroflexusL.) and black nightshade (Solanum nigrumL.). Circadian rhythmic leaf movements that appeared to be under endogenous control were found in jimson-weed (Datura stramoniumL.), common lambsquarters (Chenopodium albumL.), common cocklebur (Xanthium pensylvanicumWallr.), prickly sida (Sida spinosaL.), sicklepod (Cassia obtusifoliaL.), and coffee senna (Cassia occidentalisL.).
Yield and Quality of Two Cool-Season Grasses as Affected by Selected Herbicides
Authors: McCarty M. K.
Published: May 2019

Several herbicides applied either in the fall or spring at rates used for musk thistle (Carduus nutansL.) control had no deleterious effects on two cool-season grasses, smooth brome (Bromus inermisLeyss.) and intermediate wheatgrass [Agropyron intermedium(Host) Beauv.]. Herbicides used were 2,4-D [(2,4-dichlorophenoxy)acetic acid], 2,4,5-T [(2,4,5-trichlorophenoxy)acetic acid], dicamba (3,6-dichloro-o-anisic acid), picloram (4-amino-3,5,6-trichloropicolinic acid), triclopyr {[(3,5,6-trichloro-2-pyridinyl)oxy] acetic acid}, and Dowco 290 (3,6-dichloropicolinic acid). Atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] was included for comparative purposes because it is known to affect the protein content of some forage grasses. Effects on the quality of the forages were measured by in vitro dry matter disappearance (IVDMD), protein and KNO3determinations. Intermediate wheatgrass was less susceptible to damage from the highest rates of picloram and atrazine than smooth brome.
Metabolic Sites of Action of Fluridone in Isolated Mesophyll Cells
Authors: Rafii Z. E. , Ashton F. M. , Glenn R. K.
Published: May 2019

Time- and concentration-course studies were conducted to determine the metabolic sites of action of fluridone {1-methyl-3-phenyl-5-[3-(trifluoromethyl)phenyl]-4(1H)-pyridinone} in isolated mesophyll cells of cotton (Gossypium hirsutumL. ‘Acala SJ-1′) and red kidney bean (Phaseolus vulgarisL.). Cotton is resistant and bean is susceptible to fluridone. The herbicide was not metabolized in cells of either species during the 2-h incubation period. At the highest concentration (10-4M) and longest incubation time (2 h), fluridone inhibited photosynthesis, RNA synthesis, and protein synthesis 59, 56, and 32%, respectively in bean and 24, 21, and 14% in cotton. Lipid synthesis and dark respiration were only slightly affected. The lowest concentration and the shortest incubation period that inhibited photosynthesis, RNA synthesis, and protein synthesis in bean did not have any significant effect in cotton. The difference in responses may contribute to the selectivity of the herbicide. Although photosynthesis appeared to be the primary site of action, RNA synthesis was also markedly inhibited. These inhibitions and the somewhat lower inhibition of protein synthesis may ultimately contribute to the herbicidal action of fluridone in the intact plant.
In Vivo and In Vitro Characterization of the Foliar Entry of Glyphosate in Hemp Dogbane (Apocynum cannabinum)
Authors: Richard E. P. , Slife F. W.
Published: May 2019

Detached leaves of hemp dogbane (Apocynum cannabinumL.) were treated with14C-glyphosate [N-(phosphonomethyl)glycine] with and without adjuvants in the treatment solution. In the absence of adjuvants,14C absorption was not significant after the first 30 min harvest. Adjuvants increased the amount of glyphosate initially absorbed but did not extend the period of absorption. The pattern of glyphosate absorption in isolated leaf cells was similar to the pattern found in detached leaves. Significant absorption was obtained at the first 15-min sampling with no additional absorption occurring during the remainder of the 2-h incubation period. The quantity of14C absorbed by cells was proportional to the external concentration, but the pattern of cellular absorption was unaffected by the glyphosate concentration. After 2 h of incubation, an average of 0.1% of the glyphosate had been absorbed by the leaf cells. In similar studies using14C-leucine, 1.0% of the14C was absorbed after 2 h with absorption still increasing in a linear fashion. A uniform distribution of14C was obtained in detached leaves that had absorbed14C-glyphosate through the stem. In vitro and in vivo binding studies indicated this absorbed14C was not tightly bound to cellular components and was probably free to be absorbed by and translocated out of the cells. Since the absorption pattern in detached leaves was similar to the pattern obtained in isolated cells, cellular absorption appears to represent the major barrier in the foliar absorption of glyphosate by hemp dogbane.
Survival of Seed and Tubers of Dwarf Spikerush (Eleocharis coloradoensis) After Exposure to Extreme Temperatures
Authors: Yeo Richard R. , Thurston Jon R.
Published: May 2019

Seed and tubers and dwarf spikerush [Eleocharis coloradoensis(Britt.) Gilly] survived extremely cold and hot temperatures if damp-dried before exposure. Damp-dried seed survived 14 days exposure to −196 C and 21 days exposure to 72 C, and then germinated 59 and 24%, respectively. Seed submersed in water germinated 20% when exposed to −15 C for 30 days and 4% when exposed to 60 C for 3 days. When damp-dried seed were warmed at 37 C for 21 days the germination was nearly twice that for wet seed treated similarly. Tubers that were damp-dried before exposure survived −196 C for 14 days and 49 C for 21 days and then germinated 20 and 49%, respectively. Tubers that were exposed wet to hot or cold temperatures were killed at less extreme temperatures than seed. None of the tubers exposed wet survivied −15 C for 30 days or 49 C for 3 days.
Weed and Disease Responses to Herbicides in Single- and Double-Row Cotton (Gossypium hirsutum)
Authors: Miller J. H. , Carter C. H. , Garber R. H. , DeVay J. E.
Published: May 2019

For 3 yr, herbicide treatments of preplant trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine), postemergence diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea], both herbicides, or none were superimposed on cotton (Gossypium hirsutumL. ‘Acala SJ-2′) grown on beds centered at 102 cm using a single row or two rows spaced 28 cm apart. Cotton stand, after thinning, was 5.1 plants/m in each cotton row. Herbicides controlled annual weeds regardless of planting pattern. Cultivation, without herbicides, controlled annual grass weeds much better in cotton grown in single rows than in double rows. Preplant applications of trifluralin did not influence populations of cotton plants, regardless of row pattern. Single- and double-row plots treated with trifluralin always yielded more than untreated double rows. In two of three seasons, however, single-row plots without herbicides yielded as much as those treated with trifluralin. The lower yields in the double-row cotton were associated with reduced annual grass control especially in plots not treated with trifluralin. Weed control treatments or planting patterns did not influence the occurrence ofPythium ultimumTrow orRhizoctonia solaniKühn on cotton seedlings. The presence ofThielaviopsis basicola(Berk & Br.) Ferr. on cotton seedlings was not influenced by planting pattern but was increased by trifluralin in the third year of the study. Percentage of cotton plants with symptoms of verticillium wilt (Verticillium dahliaeKleb.) was not influenced by weed control treatments, but the percentage of diseased plants was higher in single-row than in double-row planting patterns. We attribute this response to fewer plants per hectare in single rows compared to double rows.
Adsorption and Diffusion of Dinitroaniline Herbicides in Soils
Authors: Jacques G. L. , Harvey R. G.
Published: May 2019

Adsorption of benefin (N-butyl-N-ethyl-α,α,α-trifluoro-2,6-dinitro-p-toluidine), dinitramine (N4,N4-diethyl-α,α,α-trifluoro-3,5-dinitrotoluene-2,4-diamine), fluchloralin [N-(2-chloroethyl)-2,6-dinitro-N-propyl-4-(trifluoromethyl)aniline], oryzalin (3,5-dinitro-N4,N4-dipropylsulfanilamide), profluralin [N-(cyclopropylmethyl)-α,α,α-tri-fluoro-2,6-dinitro-N-propyl-p-toluidine], and trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) was studied in 10 Wisconsin soils. Ratios of the quantity of each herbicide adsorbed and quantities remaining in the soil solution at equilibrium (Kd value) on a Piano silt loam (Typic Argiudoll fine-silty, mixed, mesic) remained relatively constant over a range of concentrations. Herbicide adsorption by the soils was related more closely to soil organic matter than to the other soil chemical and physical properties. Diffusion of the herbicides in Piano silt loam was affected by soil water. Diffusion of trifluralin, profluralin and benefin decreased as soil water increased. Diffusion of dinitramine and fluchloralin did not change significantly with change in water content. Diffusion of oryzalin increased at the highest soil water content. None of the herbicides moved more than 10 mm in the soil during a 17-day period. In unsaturated Piano silt loam, relative mobility of the herbicides was trifluralin ≥benefin>profluralin>fluchloralin>dinitramine≥oryzalin. Oryzalin reached highest mobility in water-saturated soil.
Use of Adsorption Coefficients and Soil Properties to Predict Fluridone Herbicidal Activity
Authors: Loh A. , Parka S. J. , Albritton R. , Lin C. C.
Published: May 2019

The rate of herbicide required to reduce growth of grain sorghum (Sorghum vulgare, Per. ‘Pioneer 8417′) by 50% (GR50) and soil adsorption coefficients (Ka) were determined for the experimental herbicide, fluridone {1-methyl-3-phenyl-5-[3-(trifluoromethyl)phenyl]-4(1H)-pyridinone}, in 14 soils. A linear correlation analysis was conducted between GR50values and the chemical and physical properties and fluridone absorption coefficient (Ka) for 14 soils. The GR50values were significantly correlated to soil organic matter and Ka. A stepwise regression analysis suggests that Kaor organic matter content can be used to predict the rate of fluridone application required for herbicidal activity.
EPTC Plus R-25788 Injury to Corn (Zea Mays) as Affected by Plant Age at Treatment
Authors: Burt G. W. , Buzio C. A.
Published: May 2019

The susceptibility of corn (Zea maysL. ‘Pioneer 3334A’) at different stages of growth to EPTC (S-ethyl dipropylthiocarbamate) plus a herbicide-protectant, R-25788 (N,N-diallyl-2,2-dichloroacetamide), was studied in the greenhouse. Corn was treated with either 25 ppm or 12.5 ppm EPTC containing R-25788 at planting and at 2, 4, 6, and 8 weeks thereafter. The herbicide was soil-applied and immediately incorporated by watering. Phytotoxicity and plant height were observed periodically for 56 days after herbicide treatment. Within 21 days after treatment with 25 ppm EPTC containing R-25788, injury and plant height reduction occurred in corn treated at planting, or at 2 and 4 weeks but not at 6 or 8 weeks after planting. At 56 days, however, corn treated at planting or 2 weeks after planting had outgrown all injury symptoms and was as tall as the controls (>84%). Corn treated at 4 weeks after planting, however, still remained injured and was 45% as tall as its respective control. Corn treated at 6 to 8 weeks showed no injury during the entire period of observations. The data indicates that corn is most susceptible to EPTC plus R-25788 at 4 weeks after planting. The results of this greenhouse study are discussed in relation to corn injury as observed in the field.
Effects of Chilling on Cotton (Gossypium hirsutum), Velvetleaf (Abutilon theophrasti), and Spurred Anoda (Anoda cristata)
Authors: Patterson D. T. , Flint E. P.
Published: May 2019

The effects of short exposures to low temperature on cotton (Gossypium hirsutumL. ‘Stoneville 213′), velvetleaf (Abutilon theophrastiMedic), and spurred anoda [Anoda cristata(L.) Schlecht.] were studied in controlled environment chambers. A 3-day exposure to 17/13 C day/night temperatures 24 days after planting significantly reduced dry weight, leaf area and height in all three species when compared to control plants maintained at 26/21 C day/night. After subsequent periods of 7 days at 26/21 C and 8 days at 29/23 C, the two weed species recovered in growth more completely than did cotton. Therefore, the weed/crop ratios for dry weight and leaf area were increased by the imposition of the cold treatment. Mathematical analysis of the growth of the three species indicated that the growth reductions during the cold treatment were caused by decreases in both net assimilation rate and leaf area duration. The net photosynthetic rates and stomatal conductances of individual leaves of cotton and velvetleaf were significantly reduced during the cold treatment but recovered to control levels during a subsequent 4-day exposure to 26/21 C. We conclude that the adverse effects of low temperatures on the growth of cotton, velvetleaf, and spurred anoda are caused mainly by reductions in leaf area production. Because of its slower and less complete recovery, cotton is more severely affected by low temperature than either of the two weeds. Our results help explain the observation that velvetleaf and spurred anoda are more competitive with cotton following abnormally cool periods early in the growing season.
Dicamba Volatility
Authors: Behrens Richard , Lueschen W. E.
Published: May 2019

Factors influencing dicamba drift, especially vapor drift, were examined in field and growth chamber studies. In field experiments, potted soybeans[Glycine max(L.) Merr.]. exposed to vapors arising from corn (Zea maysL.) foliarly treated with the sodium (Na), dimethylamine (DMA), diethanolamine (DEOA), orN-tallow-N,N1,N1-trimethyl-1,3-diaminopropane (TA) salts of dicamba (3,6-dichloro-o-anisic acid), developed dicamba injury symptoms. Dicamba volatilization from treated corn was detected with soybeans for 3 days after the application. Dicamba vapors caused symptoms on soybeans placed up to 60m downwind of the treated corn. When vapor and/or spray drift caused soybean terminal bud kill, yields were reduced. In growth chamber studies, dicamba volatility effects on soybeans could be reduced by lowering the temperature or increasing the relative humidity. Rainfall of 1mm or more on treated corn ended dicamba volatilization. The dicamba volatilization was greater from corn and soybean leaves than from velvetleaf (Abutilon theophrastiMedic.) leaves and blotter paper. The volatilization of dicamba formulations varied in growth chamber comparisons with the acid being most volatile and the inorganic salts being the least volatile. However, under field conditions, use of less volatile formulations did not eliminate dicamba symptoms on soybeans. The volatile component of the commercial DMA salt of dicamba was identified by gas chromatography-mass spectrometry as free dicamba acid.
The Long-Term Effect of Picloram and Its Residue on Grain Production and Weed Control
Authors: Kirkland K. J. , Keys C. H.
Published: May 2019

The persistence of picloram (4-amino-3,5,6-trichloropicolinic acid) was measured each spring over an 8-yr period following repeated annual applications at rates ranging from 0.020 to 0.070 kg/ha. Picloram residue levels were proportional to rate of application but averaged approximately 45% of the original levels when measured 12 months following application and declined to 10% 24 months after application ceased. Control of wild buckwheat (Polygonum convolvulusL.) was good with major population declines over the test period. Crop tolerance and yields were not affected at rates of 0.035 kg/ha or less.
Control of Winged Waterprimrose (Jussiaea decurrens) and Northern Jointvetch (Aeschynomene virginica) with Fungal Pathogens
Authors: Boyette C. D. , Templeton G. E. , Smith R. J.
Published: May 2019

An indigenous, host-specific, pathogenic fungus that parasitizes winged waterprimrose [Jussiaea decurrens(Walt.) DC.] is endemic in the rice growing region of Arkansas. The fungus was isolated and identified asColletotrichum gloeosporioides(Penz.) Sacc. f.sp. jussiaeae(CGJ). It is highly specific for parasitism of winged waterprimrose and not parasitic on creeping waterprimrose (J. repensL. var.glabrescensKtze.), rice (Oryza sativaL.), soybeans [Glycine max(L.) Merr.], cotton (Gossypium hirsutumL.), or 4 other crops and 13 other weeds. The fungus was physiologically distinct from C.gloeosporioides(Penz.) Sacc. f. sp.aeschynomene(CGA), an endemic anthracnose pathogen of northern jointvetch[Aeschynomene virginica(L.) B.S.P.], as indicated by cross inoculations of both weeds. Culture in the laboratory and inoculation of winged waterprimrose in greenhouse, growth chamber and field experiments indicated that the pathogen was stable, specific, and virulent in a wide range of environments. The pathogen yielded large quantities of spores in liquid culture. It is suitable for control of winged waterprimrose. Winged waterprimrose and northern jointvetch were controlled in greenhouse and field tests by application of spore mixtures of CGJ and CGA at concentrations of 1 to 2 million spores/ml of each fungus in 94 L/ha of water; the fungi did not damage rice or nontarget crops.
Toxicological Investigations on Galenia pubescens
Authors: Williams M. C.
Published: May 2019

Toxicological investigations were conducted on galenia [Galenia pubescens (Eckl. and Zeyh.) Druce], an introduced species of the family Aizoaceae. One lot of field-grown galenia assayed 2.5% nitrate (as KNO3) and 6.1% soluble oxalates. Three sheep were acutely poisoned after they were gavaged with this plant. Galenia grown in nutrient solution assayed 6% nitrate and 11.3% soluble oxalates. Chicks fed this material died of nitrate and oxalate poisoning. Galenia may accumulate toxic levels of both oxalates and nitrates and thus should be classed as a poisonous plant that would be considered hazardous to humans and livestock.
The Distribution of Leafy Spurge (Euphorbia esula) and Other WeedyEuphorbiaspp. in the United States
Authors: Dunn P. H.
Published: May 2019

A survey was made in the United States to determine the extent of the infestations of leafy spurge (Euphorbia esulaL.) and other weeds of economic importance in the Euphorbiaceae. From introductions about 100 yr ago, leafy spurge is now found in 458 counties in 26 states from coast to coast. The infestations are out of control in some states, and biological control is mentioned as a possible solution to the problem.
Weed Control in Sugarbeets (Beta vulgaris) by Mixtures of Cycloate and Ethofumesate
Authors: Schweizer E. E.
Published: May 2019

Response of weeds and sugarbeets (Beta vulgaris L. ‘Mono Hy D2′) to preplanting treatments of mixtures of cycloate (S-ethyl N-ethylthiocyclohexanecarbamate) and ethofumesate [(±)-2-ethoxy-2,3-dihydro-3,3-dimethyl-5-benzofuranyl methanesulfonate] was evaluated in five field studies. A mixture containing 1.7 kg/ha of each herbicide reduced the stand of common lambsquarters (Chenopodium album L.) 90%, green foxtail [Setaria viridis (L.) Beauv.] and yellow foxtail [Setaria lutescens (Weigel) Hubb.] 97 to 99%, kochia [Kochia scoparia (L.) Schrad.] 64 to 77%, and redroot pigweed (Amaranthus retroflexus L.) 82 to 99%. The response of weeds to preplanting applications of mixtures of cycloate and ethofumesate was independent of soil texture, whereas response of sugarbeets was dependent on soil texture. The herbicide mixtures significantly reduced the pre-thinning stand of sugarbeets and root and sucrose yields on two sandy loams, but not on a clay loam.
Seedbed Tillage and Herbicide Influence on Soybean (Glycine max) Weed Control and Yield
Authors: Kapusta George
Published: May 2019

Twenty herbicide treatments were evaluated on conventional-till (plow, disc, and harrow), minimum-till (disc only), and no-till planted soybeans [Glycine max(L.) Merr.] from 1976 through 1978 at the Belleville Research Center in St. Clair County, Illinois. The soil type was a Weir silt loam (Typic Ochraqualf) characterized by poor internal drainage and 1.2% organic matter. Weed population by species, weed control, and soybean population, injury, and yield were obtained. Fall panicum (Panicum dichotomiflorumMichx.) and giant foxtail (Setaria faberiHerrm.) were the dominant species in all tillage systems, exceeding 1 million plants/ha in the conventional and no-till plots. These species and ivyleaf morningglory [Ipomoea hederacea(L.) Jacq.] were the most difficult to control each year. Weed control was the poorest in the no-till plots because of the large size of the weeds at the time of herbicide application, insufficient rainfall following, and because the plots were not cultivated. The soybean population was equal in all tillage systems except in 1976 when the no-till population exceeded that in the other tillage systems. Treatments that included oryzalin (3,5-dinitro-N4,N4-dipropylsulfanilamide) caused 42 and 35% soybean injury in the 1976 minimum and no-till plots, respectively. Postemergence-applied naptalam (N-1-naphthylphthalamic acid) plus dinoseb (2-sec-butyl-4,6-dinitrophenol) caused leaf burn each year that ranged from 5 to 35% but all plants recovered within several weeks of application. The seedbed tillage method and herbicide treatments did not significantly affect soybean yields in 1976 when all the herbicides were effective. No-till yields in 1977 and 1978 were substantially lower than yields in conventional and minimum-till plots because of poor weed control. Soybean yields were 2506, 2466, and 1714 kg/ha in the conventional-till, minimum-till, and no-till plots, respectively, when averaged over the 3 yr and 20 herbicide treatments.