bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Prometryn, Diuron, Fluometuron, and MSMA on Chlorella and Two Fungi
Authors: Davis D. E. , Pillai C. G. P. , Truelove B.
Published: May 2019

The effects of prometryn [2,4-bis(isopropylamino)-6-(methylthio)-s-triazine], diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea], fluometuron [1,1-dimethyl-3-(a,a,a-trifluoro-m-tolyl)urea], and MSMA (monosodium methanearsonate) onChlorella pyrenoidosaChick ‘Strain 252′,Trichoderma viridePers. ex Fr., andAspergillus terreusThom were investigated. Minimum herbicide concentrations necessary to decreaseC. pyrenoidosagrowth after exposure for 35 generations were 10-8M diuron, 10-7M prometryn, and 10-6M fluometuron. MSMA had no effect.C. pyrenoidosaphotosynthesis was essentially stopped by a 2-hr exposure to 5 × 10-6M prometryn or diuron and by 5 × 10-5M fluometuron. Prometryn (5 × 10-5M) or diuron (5 × 10-7M) increased respiration by 70 and 44%, respectively after an 80-min treatment. Maximum fluometuron inhibition of respiration was ca 25% and MSMA had little or no effect. Herbicide concentrations of 0, 10-6, 10-5, and 10-4M were used to measure their effects on colony diameter growth, gain in mycelial dry weight, sporulation, and respiration of the two fungi. No concentration of any of the herbicides had any major effect on any of these parameters except sporulation.T. viridesporulation was increased approximately 20, 30, 35, and 50% by 10-6M concentrations of prometryn, diuron, fluometuron, and MSMA, respectively. Sporulation ofA. terreuswas also somewhat increased by these herbicides.
Early Chemical Control of Weeds in Europe
Authors: Smith Allan E. , Secoy D. M.
Published: May 2019

A brief history of chemical weed control in Europe from ancient Greek and Roman times to 1850 is given. The use of the various chemicals recorded is discussed and their possible efficacy commented upon.
Herbicidal Weed Control in Stubble No-Till Planted Corn
Authors: Kapusta George , Strieker C.F.
Published: May 2019

Several dozen herbicide systems were evaluated over a 4-yr period for weed control in stubble no-till planted corn (Zea maysL.). Crop tolerance and corn yield data also were obtained. Paraquat (1,1′-dimethyl-4,4′-bipyridinium ion) and glyphosate [N-(phosphonomethyl)glycine] afforded excellent desiccation of all emerged vegetation each year. The oil-soluble formulation of dinoseb (2-sec-butyl-4,6-dinitrophenol) also afforded complete contact control of emerged vegetation in 1975, the only year it was evaluated. A herbicide system consisting of an acetanilide plus a triazine afforded the most consistent residual weed control. The specific herbicides affording satisfactory control largely depended on the weed spectrum. Fall panicum (Panicum dichotomiflorumMichx.), large crabgrass [Digitaria sanguinalis(L.) Scop.], and yellow nutsedge (Cyperus esculentusL.) were the weeds most difficult to control with the herbicide systems used in these studies. Corn yields were influenced primarily by the degree of weed control achieved, and in several instances by secondary effects of stand reduction or injury.
Cycloate and Phenmedipham as Complementary Treatments in Sugarbeets
Authors: Dawson J. H.
Published: May 2019

Cycloate (S-ethylN-ethylthiocyclohexanecarbamate), applied by subsurface injection at 3.4 kg/ha, controlled 98 to 100% of barnyardgrass [Echinochloa crus-galli(L.) Beauv.] and 82 to 94% of common lambsquarters (Chenopodium albumL.) and hairy nightshade (Solarium sarachoidesSendt.). Phenmedipham (methylm-hydroxycarbanilatem-methylcarbanilate) at 1.1 kg/ha, applied after sugarbeets had emerged but before common lambsquarters had more than three pairs of true leaves or hairy nightshade had more than three or four true leaves, controlled the members of these species that had survived cycloate. Cycloate preconditioned sugarbeets and the surviving broadleaf weeds to injury be phenmedipham. Although applying phenmedipham following cycloate before sugarbeets had two pairs of true leaves sometimes resulted in severe crop injury, and applying it when weeds were too large resulted in incomplete weed control, in all experiments there was a period of at least 2 weeks during which application of phenmedipham killed the surviving lambsquarters and nightshade without injuring sugarbeets.
Wild Oat Control in Kentucky Bluegrass and Perennial Ryegrass
Authors: Lee W. O.
Published: May 2019

MSMA (Monosodium methanearsonate) applied postemergence at 4.5, 6.7, or 9.0 kg/ha controlled wild oat (Avena fatuaL.) in new plantings of Kentucky bluegrass (Poa pratensisL. ‘Pennstar’) and in perennial ryegrass (Lolium perenneL. ‘Reveille,’ ‘Pennfine’). MSMA at 4.5 kg/ha was almost as effective as the higher rates in controlling wild oat. MSMA at 2.2 kg/ha was less effective in some experiments. Visual injury to the perennial grasses was negligible. Satisfactory grass stands developed at all MSMA rates. Perennial ryegrass seed yields were higher than the untreated check in most experiments when MSMA was applied at 4.5, 6.7, or 9.0 kg/ha before the grass reached the boot stage. When MSMA was applied after the ryegrass reached the boot stage, some of the treatments reduced ‘Reveille’ perennial ryegrass seed production.
A Rainfall Simulator for Pesticide Leaching Studies
Authors: Brockman F. E. , Duke W. B. , Hunt J. F.
Published: May 2019

The construction and operation of an apparatus for applying rainfall to soil columns being used for pesticide leaching studies is described. The apparatus will uniformly deliver water to many soil columns over a wide range of natural rainfall rates.
Effects of Glyphosate on Chloroplast Ultrastructure of Quackgrass Mesophyll Cells
Authors: Campbell W. F. , Evans J. O. , Reed S. C.
Published: May 2019

Phytotoxicity of glyphosate (N-(phosphonomethyl) glycine), applied at 0, 0.56, 1.12, 1.68, 2.24 and 4.49 kg ai/ha to uniform, naturally growing quackgrass, [Agropyron repens (L.) Beauv.] plants, was studied with the electron microscope. Visible damage (yellowing of the leaves) to the plants was observed at the 2.24 and 4.49 kg ai/ha dosage rates within 72 hr. Similar damage became evident 120 hr after treatment at the 0.56 to 1.68 dosages. Leaf discs (1 mm in diameter) were harvested at 24, 48, 96, and 192 hr and prepared for electron microscopy by standard techniques. Cellular damage could be detected at all dosage rates as early as 24 hr after treatment. The type of damage observed was partial to complete disruption of the chloroplast envelope, and swelling of the rough endoplasmic reticulum (RER) with a subsequent formation of vesicles. With loss of integrity of the envelope, the chloroplast became completely disrupted with increased time. Other organelles within the cell were also destroyed.
Response of Two Yellow Nutsedge Varieties to Three Herbicides
Authors: Costa Jaime , Appleby Arnold P.
Published: May 2019

In greenhouse studies,Cyperus esculentusL. var.esculentuswas less susceptible thanC. esculentusL. var.leptostachyusBoeck. to preplant applications of 1.77 kg/ha of atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] or 0.5 kg/ha of metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazine-5-(4H)one].C.var.esculentuswas more susceptible thanC.var.leptostachyusto postemergence applications of 2,4-D [(2,4-dichlorophenoxy)acetic acid] oil-soluble amine.C.var.esculentushad longer, slightly narrower, and more upright leaves; generally fewer but larger tubers; fewer rhizomes; and a lower frequency of flowers with less seeds per inflorescence thanC.var.leptostachyus.Publications onC. esculentusshould specify which variety was used.
Dispersal ofRhinocyllus conicusfor Biocontrol of Musk Thistle
Authors: Hodgson J. M. , Rees N. E.
Published: May 2019

A weevil [Rhinocyllus conicus(Froelich)] host specific toCarduus, Cirsium, Silybum, andOnopordum, was introduced into Gallatin County, Montana, for biocontrol of musk thistle (Carduus nutansL.). Releases were made in 1969, 1971, 1972, and 1973 on local musk thistle infestations. The insects became established and overwintered successfully. In 1974,R. conicuswas found over a 1,280-km2area of the county in seed heads of musk thistle. Weevil larvae severely infected the primary flowers, but only a few secondary and later flowers were attacked. Seed production from infected primary flowers was greatly reduced, and other factors influenced reduction of seeds from secondary and later flowers.
Performance of Carbon-Coated Rice Seed on Flooded Soil
Authors: Nangju D. , Plucknett D. L. , Obien S. R.
Published: May 2019

Pelleting rice (Oryza sativaL., ‘IR8′) seeds with activated carbon was developed as a means of overcoming herbicide phytotoxicity to direct-seeded, flooded rice. Field and greenhouse experiments showed that pregerminated rice seeds coated three times with activated carbon with 50% polyvinyl acetate as an adhesive, were adequately protected from the injurious effects of chloramben (3-amino-2,5-dichlorobenzoic acid), butachlor [N-(butoxymethyl)-2-chloro-2′,6′-diethylacetanilide] and oxadiazon [2-tert-butyl-4-(2,4-dichloro-5-isopropoxyphenyl)-Δ2-1,3,4-oxadiazolin-5-one]. The performance of carbon-coated rice seeds in flooded soil, however, was dependent on time of flooding, method and rate of sowing, rate and time of herbicide application, and quality of activated carbon.
Effect of Temperature on Response of Tomatoes to Several Dinitroaniline Herbicides and Phosphorus
Authors: Wilson H. P. , Stewart F. B. , Hines T. E.
Published: May 2019

Effects of temperature on response of transplanted tomatoes (Lycopersicon esculentumMill. ‘Campbell 17′) to trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine), nitralin [4-(methylsulfonyl)-2,6-dinitro-N,N-dipropylaniline], profluralin [N-(cyclopropylmethyl)-α,α,α-trifluoro-2,6-dinitro-N-propyl-p-toluidine], and isopropalin (2,6-dinitro-N,N-dipropylcumidine) were investigated in field studies. Trifluralin and nitralin caused greater reductions in growth and yields of tomatoes transplanted early in April than to tomatoes transplanted around May 1. Responses to profluralin were similar but total yields of early transplanted tomatoes were not reduced although initial yields were below those of tomatoes treated with isopropalin. In controlled environment chamber studies, percent phosphorus of plant tops was reduced by trifluralin at low temperatures but was not influenced by trifluralin at high temperatures. Tomoto responses to phosphorus as reflected by plant fresh weight, dry weight and phosphorus content (mg/plant) were reduced by trifluralin at low and high temperatures.
Differential Response of Potato Cultivars to Metribuzin
Authors: Graf G. T. , Ogg A. G.
Published: May 2019

In greenhouse studies, 11 cultivars of potato (Solanum tuberosum L.) responded differently to foliar applications of metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazine-5-(4H)one] at rates of 0.14 to 1.12 kg/ha. The first symptoms of metribuzin injury varied among cultivars. When measured 14 days after treatment, the dry weight was reduced more than the height or the vigor. Height was least affected. When metribuzin was applied at 0.14 kg/ha, the height of ‘Norchip,’ the vigor of ‘Norland,’ ‘Norchip,’ and ‘White Rose,’ and the dry weight of ‘Red La Soda,’ ‘Cascade,’ ‘Norchip,’ and ‘White Rose’ were reduced significantly 14 days after treatment. Plant vigor and dry weight of all of the cultivars were reduced significantly by metribuzin applied at 1.12 kg/ha. ‘Nooksack’ and ‘Norgold’ were the most tolerant to foliar applications of metribuzin, and ‘Norchip’ and ‘White Rose’ were the most susceptible.
Differential Tolerance of Tomato Cultivars to Metribuzin
Authors: Stephenson G. R. , McLeod J. E. , Phatak S. C.
Published: May 2019

Seedlings of fifteen different cultivars of tomato (Lycopersicon esculentumMill.) varied greatly in tolerance to metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazine-5(4H) one] applied at a concentration of 0.5 mg/L in quartz sand nutrient culture during the three-true-leaf stage. Tolerance increased with seedling age, but acceptable tolerance was observed about 6 days earlier in the tolerant ‘Fireball’ compared to the susceptible ‘Heinz 1706′. Root uptake and acropetal translocation of metribuzin-carbonyl-14C was similar in 2-week-old seedlings of susceptible Heinz 1706 and tolerant Fireball seedlings. Differential tolerance was related to the rate of detoxification by metabolism within the tomato leaves, which was approximatley two-fold greater in the tolerant Fireball seedlings.
Response of Prickly Sida and Soybeans to Various Herbicides
Authors: Jeffery Larry S. , Connell John , McCutchen Tom , Overton Joseph R.
Published: May 2019

Three preemergence and four postemergence herbicides were compared for control of prickly sida (Sida spinosaL.) in soybeans (Glycine maxMerrill) and for level of phytotoxicity to soybeans. As a preemergence herbicide, chlorbromuron [3-(4-bromo-3-chlorophenyl)-1-methoxyl-1-methylurea] provided better control of prickly sida than did linuron [3-(3,4-dichlorophenyl)-1-methoxyl-1-methylurea] which was more consistently effective than was naptalam (N-1-naphthylphthalamic acid) plus dinoseb (2-sec-butyl-4,6-dinitrophenol). Chlorbromuron applied as a preemergence treatment caused slight crop injury. In most cases preemergence treatments followed by cultivation were effective in providing season-long control. The descending order of effectiveness for prickly sida control by the postemergence herbicides was: chlorbromuronmetribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazine-5(4H)one] > prometryne [2,4-bis(isopropylamino)-6-(methylthio)-s-triazine] > dinoseb. Prometryne as a postemergence treatment following a preemergence herbicide increased prickly sida control more consistently than dinoseb used as the postemergence treatment. However, prometryne caused more crop injury than did dinoseb.

Comparison of soybean yields from the weedy and weed free checks show that prickly sida caused only 9 to 14% yield losses in soybeans.
A Root Isolation Method for Testing Root-Active Chemicals
Authors: Duffy S. L.
Published: May 2019

A method for isolating roots of a growing plant was devised. The technique allows treatment of an isolated portion of the root system without disturbance or injury to the untreated root mass. A specially designed planter-box was used to induce natural separation of the root system in 3 to 4 weeks. Weeping willow (Salix babylonica L.) seedlings were used to test the performance of dichlobenil (2,6-dichlorobenzonitrile), paraquat (1,1′-dimethyl-4,4′-bipyridinium ion), sodium hydroxide (NaOH), and copper sulfate (CuSO4 • 5H2O) in reducing the viability of treated roots. A tetrazolium chloride assay was used to determine the difference in viability of the treated roots. Copper sulfate and paraquat-treated plants produced symptoms of systemic injury.
Vaporization and Uptake of Atrazine with Additives
Authors: Nalewaja J. D. , Adamczewski K. A.
Published: May 2019

The loss of atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] from metal planchets was decreased by an increase in the amount applied and linseed oil (LO) additive. LO reduced volatility to a greater extent than did other additives. Vapor loss from plant leaves was influenced by plant species, plant leaf maturity, soil moisture, concentration of atrazine applied, volume of oil additive, type of additive, and duration of exposure. Generally, atrazine uptake by plants was inversely related to volatility. Uptake and translocation of14C-atrazine label was increased more by oil additives than surfactant (SURF) compared to no additive. LO increased14C-label translocation more in yellow foxtail [Setaria glauca lutescens(Weigel) Hubb.], green foxtail [Setaria viridis(L.) Beauv.], and barnyardgrass [Echinchloa crus-galli(L.) Beauv.] than in corn (Zea maysL.).
Effect of Seed Treatment on Germination of Wild Safflower
Authors: Bassiri Abdollah , Rouhani Iraj
Published: May 2019

Seeds of wild safflower (Carthamus oxyacanthaBieb.) collected from the Bajgah area, Iran, in 2 successive years were subjected to stratification and scarification treatments and their germination percentage and subsequent seedling growth (length) were measured at room temperature (23 ± 2 C). Maximum germination and seedling length occurred in the seeds stratified in moist sand at 4 C for 2 weeks. The response of the freshly-harvested seed to scarification was linear while that for 1-yr-old seed was quadratic. Both scarification and stratification independently increased germination but germination never reached the viability level of the seed.
Cotyledon Disc Bioassay for Certain Herbicides
Authors: Da Silva J. F. , Fadayomi R. O. , Warren G. F.
Published: May 2019

A rapid cotyledon disc bioassay developed for photosynthetic inhibitors was tested on several herbicides of different modes of action. In addition to being an excellent bioassay method for photosynthetic inhibitors it was found to be useful for the detection of diquat (6,7-dihydrodipyrido[1,2-α:2′,1′-c] pyrazine-diium ion), paraquat (1,1′-dimethyl-4,4′-dipyridinium ion), and dinoseb (2-sec-butyl-4,6-dinitrophenol). Herbicides representing several other modes of action could not be readily detected by this method.
Response of Monocotyledons to HOE 22870 and HOE 23408
Authors: Andersen Robert N.
Published: May 2019

In the greenhouse, postemergence treatments of 1.12 kg/ha of HOE 22870 [4-(4′-chlorophenoxy)-phenoxy-α-propionic-isobutylester] or HOE 23408 methyl 2-[4-(2,4-dichlorophenoxy)phenoxy] propanoate were applied to three perennial weeds (two grasses and one sedge) and to 27 species or varieties of annual grasses (crops and weeds). The perennials were resistant to both compounds, but control of the seedling grasses ranged from 0 to 100%, indicating the potential of controlling certain grass weeds in certain grass crops, as well as in broadleaf crops. Generally, the response of a given species was similar for both compounds. However, on some grasses one compound was considerably more effective than the other. Seven species or varieties of foxtail (Setariaspp.) were treated with various rates of either compound. Differential responses were observed, but it appeared that all the foxtail species or varieties studied should probably be controllable with HOE 23408. All but yellow foxtail [Setaria lutescens(Weigel) Hubb.], should probably be controllable with HOE 22870.
Studies on Nitralin Residues in Soils
Authors: Miller C. H. , Monaco T. J. , Sheets T. J.
Published: May 2019

Experiments involving the application of nitralin [4-(methylsulfonyl)-2,6-dinitro-N,N-dipropylaniline] at 0.56, 1.12, or 1.68 kg/ha on each of three successive plantings of pickling cucumbers (Cucumis sativusL. ‘Explorer’) were conducted during a 2-yr period. Residues of nitralin in soil increased with rate and number of applications. Nitralin residues accumulated to higher concentrations in a soil with 2.9% organic matter than in a soil with 0.7% organic matter. However, cucumber plants were injured less in the soil with the highest concentrations of herbicide. Oats (Avena sativaL. ‘Carolee’) planted following cucumbers were injured by nitralin residues resulting from the highest application rates. Bioassays and chemical analyses suggested that no appreciable soil residues of nitralin remained during the succeeding year.
Histological Effects of Ethephon and 2,4,5-T on Mesquite
Authors: Morey P. R. , Sosebee R. E. , Dahl B. E.
Published: May 2019

Six-week-old honey mesquite [Prosopis glandulosa(Torr.) var.glandulosa] seedlings were treated with various concentrations of ethephon (2-chloroethylphosphonic acid) and 2,4,5-T [(2,4,5-trichlorophenoxy)acetic acid] alone and in combinations to determine effect on stem mortality under greenhouse conditions. Ethephon alone at 0.05 g/L brought about defoliation and a reduction in xylem tissue formation but did not affect the histological development of the stem tissue. Treatment with 2,4,5-T alone at 3.2 g/L resulted in 40% stem mortality along with the formation of abnormal xylem tissue of reduced thickness. A combination of ethephon (0.05 g/L) and 2,4,5-T (3.2 g/L) significantly increased mesquite mortality. This was associated with a further reduction in xylem thickness, abnormal development of the xylem, abnormal positional relationships of vascular tissues, and initiation of adventitious roots. This study showed that ethephon in combination with 2,4,5-T was more effective than either treatment alone in promoting the disruption of the tissue systems of the stem and in increasing control of mesquite seedlings.
Transition From Overseeded Cool-Season Grass to Warm-Season Grass with Pronamide
Authors: Johnson B. J.
Published: May 2019

Field experiments were conducted for 2 yr on pronamide [3,5-dichloro-N-(1,1-dimethyl-2-propynyl)benzamide] treatments in the Piedmont region of Georgia to aid the transition of overseeded cool-season turf to warm-season turf in early spring. Pronamide applied to overseeded perennial ryegrass (Lolium perenneL. ‘Game’ and ‘Manhattan’) gradually reduced the growth of perennial ryegrass and permitted bermudagrass [Cynodon dactylon(L.) Pers. ‘Tifdwarf’] to initiate spring growth with little competition. Total turfgrass cover and turf quality ratings in pronamide treated plots were lower than ratings for untreated plots during the transition period. However, the reduction in turf quality and stand was minimal when pronamide was applied March 20 at 0.8 kg/ha. The turf quality and stand was 76 and 88% of the untreated check on April 23 and May 9, respectively, but the turf fully recovered within 2 weeks. The turf quality was higher in plots treated with pronamide on March 20 than in untreated check throughout June. The optimum date of promanide treatment in the Piedmont Region for transition of cool-season grass to warm-season grass was March 20, when compared to applications made on February 28, April 9, or April 29.
Factors Affecting Thiocarbamate Injury to Corn I. Temperature and Soil Moisture
Authors: Burt G. W. , Akinsorotan A. O.
Published: May 2019

Corn (Zea maysL.) was grown in EPTC-(S-ethyl dipropylthiocarbamate) and butylate-(S-ethyl diisobutylthiocarbamate) treated soil at 33 and 15% moisture in growth chambers at 30 and 20 C. EPTC (6 and 18 ppm) and butylate (19 and 50 ppm) reduced corn growth more at 30 than at 20 C. The days before emergence of the corn coleoptile were the most critical time for thiocarbamate injury. When plants were grown at 30 C before emergence more injury occurred at 33% soil moisture than at 15% except with butylate at 19 ppm. At 20 C, however, plants grew as tall or taller at 33% soil moisture than at 15% except for butylate at 19 ppm. Addition of R-25788 (N,N-diallyl-2,2-dichloroacetamide) to EPTC and butylate increased by about 10 times the amount of herbicide required to injure corn. With R-25788 the toxicity of these two herbicides was not influenced greatly by either temperature or soil moisture.
Atrazine Injury: Relationship to Metabolism, Substrate Level, and Secondary Factors
Authors: Shimabukuro R. H. , Masteller V. J. , Walsh W. C.
Published: May 2019

Aseptic cultures of isolated corn (Zea maysL. ‘North Dakota KE47101′) shoots and roots and soybean [Glycine max(L.) Merr. ‘Hawkeye’] seedlings absorbed and metabolized atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] similarly to plants grown and treated in nutrient solution under non-sterile conditions. Atrazine injured susceptible soybean seedlings more rapidly than can be explained on the basis of starvation alone. It is postulated that the herbicidal activity of atrazine is partly due to toxic secondary factor(s) which may be of biochemical or photochemical origin. The effect of the toxic secondary factor(s) was reversed by added sucrose independent of light.
The Effect of 2,4-D on Rapeseed
Authors: Betts M. , Ashford R.
Published: May 2019

Field experiments were conducted to compare the effects of 0.07, 0.14, 0.28, and 0.56 kg/ha of 2,4-D [(2,4-dichlorophenoxy)acetic acid] amine on plant growth, seed production, and seed quality when applied at four growth stages of summer rape (Brassica napusL. ‘Zephyr’) and turnip rape (Brassica campestrisL. ‘Span’). At all growth stages, seed yield of turnip rape, was significantly reduced by each additional increment of 2,4-D. The difference in response of the two species may relate in part to differences in spray droplet retention of the leaf surfaces. The herbicide did not affect the germination of harvested seed although treatment with the higher rates at the bolting and flowering stages resulted in the production of some shrivelled seed that was lost on cleaning. Some herbicide treatments caused a marked increase in size of harvested seed. There was a trend towards decreased seed oil content with increasing rate of 2,4-D at the bolting and flowering stages, but oil production losses were mainly reflected through losses in seed yield. The time required for both species to reach maturity increased with increasing rate of herbicide when applied at the vegetative stages. In additional field studies, 2,4-D significantly reduced seed yield in turnip rape when applied at the 3- to 4-leaf stage at 0.035 kg/ha, and 0.018 kg/ha sometimes produced visible effects without noticeable loss in yield.
Translocation of14C-Methazole in Cotton
Authors: Wills G. D.
Published: May 2019

Translocation of the14C-labeled methazole [2-(3,4-dichlorophenyl)-4-methyl-1,2,4-oxadiazolidine-3,5-dione] was determined in cotton (Gossypium hirsutumL. ‘DPL 16′) from preemergence treatments and applications to leaves and stems in the field. Significantly greater methazole concentrations occurred in cotton from treatments to stems of 18 to 22-cm tall cotton than to leaves of 10 to 12-cm tall cotton or when applied preemergence. The radiolabel translocated primarily into the mature stems and leaves with lesser amounts translocating into the roots. Little14C moved into the young growing points or into the seed and fiber of mature cotton. The distribution pattern of the14C-label is characteristic of compounds which move primarily in the apoplast.
Effectiveness of Metribuzin Applied Preemergence for Economical Control of Common Cocklebur in Soybeans
Authors: McWhorter C. G. , Anderson J. M.
Published: May 2019

The effectiveness of several preemergence and postemergence weed control systems for control of common cocklebur (Xanthium pensylvanicumWallr.) in soybeans [Glycine max(L.) Merr.] was determined in field research over a 3-yr period. Sequential applications of metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazine-5(4H)one] at 1.1 kg/ha applied preemergence, and dinoseb (2-sec-butyl-4,6-dinitrophenol) at 1.7 kg/ha, 2,4-DB [4-(2,4-dichlorophenoxy)butyric acid] at 0.2 kg/ha, or bentazon [3-isopropyl-1H-2,1,3-benzothiadiazin-(4)3H-one 2,2-dioxide] at 1.1 kg/ha applied postemergence, provided at least 90% control of common cocklebur and increased soybean yields. Use of single herbicide applications was less effective than sequential applications, but metribuzin applied preemergence was more effective in controlling common cocklebur and increasing soybean yields than single applications of any herbicide applied postemergence. Effective control of common cocklebur with sequential herbicide treatments increased soybean seed grades by reducing discounts caused by several grade lowering components including moisture content and foreign material in harvested seed. Use of all herbicide practices increased returns above specified costs, but greatest returns followed use of sequential treatments.
Influence of Row Spacing on Weed Competition by Cotton
Authors: Rogers N. K. , Buchanan G. A. , Johnson W. C.
Published: May 2019

When planted with narrow (53 cm) row spacing, cotton (Gossypium hirsutumL.) ‘McNair 210’ produced maximum yields with as little as 6 weeks of weed-free maintenance. With wider row spacing (79 and 106 cm), however, 10 and 14 weeks of weed-free maintenance were required for maximum yield. When weeds were allowed to grow in cotton for more than 2 to 4 weeks after planting, yield reductions occurred. This tolerance period did not differ with row widths of 53, 79, or 106 cm.
Role of pH on Metribuzin Dissipation in Field Soils
Authors: Ladlie James S. , Meggitt William F. , Penner Donald
Published: May 2019

Metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazine-5(4H)one] residue analysis of soil samples showed greater amounts of residue extractable at soil pH 6.7 than 4.6. Metribuzin leaching increased with increasing soil pH. Metribuzin disappearance from soil followed pseudo first-order kinetics. The half-life of metribuzin decreased as soil pH increased and increased at all soil pH levels as depth of sampling increased. The decreased activity and decreased rate of metribuzin dissipation at lower soil pH is apparently due to protonation and increased adsorption.
Turfgrass Tolerance and Weed Control with Methazole and Metribuzin
Authors: Johnson B. J.
Published: May 2019

Methazole [2-(3,4-dichlorophenyl)-4-methyl-1,2,4-oxadiazolidine-3,5-dione] and metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazine-5(4H)one] were evaluated in separate experiments for postemergence control of large crabgrass [Digitaria sanguinalis(L.) Scop.] and goosegrass [Eleusine indica(L.) Gaertn.] and on tolerance of centipedegrass [Eremochloa ophiuroides(Munro) Hack.], St. Augustinegrass [Stenotaphrum secundatum(Walt.) Kuntze], and bermudagrass [Cynodon dactylon(L.) Pers. ‘Common’]. Methazole was also evaluated on tolerance of Kentucky bluegrass (Poa pratensisL. ‘Common’). Metribuzin applied at 0.6 kg/ha and methazole at 1.1 kg/ha as single treatments controlled 82 and 87% goosegrass, respectively. Repeated treatments were needed for similar control of large crabgrass. These treatments did not permanently injure bermudagrass or centipedegrass. St. Augustinegrass was severely injured when treated with single applications of methazole at 1.1 kg/ha or metribuzin at 0.6 kg/ha while Kentucky bluegrass was severely injured by methazole applied at any rate. Methazole caused moderate to severe injury to bermudagrass when applied at 2.2 kg/ha in each of two applications and to centipedegrass when applied at 4.4 kg/ha in each of two applications.
CONTENUTI E COMPORTAMENTI LEGISLATIVI NEL PARLAMENTO ITALIANO
Authors: Di Palma Giuseppe
Published: May 2019

Introduzione

Quale tipo di comportamento e di legislazione caratterizza un Parlamento come il nostro, diviso tra una maggioranza democristiana al potere e un'opposizione comunista agguerrita, disciplinata, e in costante crescita elettorale? Poiché l'egemonia democristiana è fatto ormai trentennale, a un osservatore meno che attento potrebbe sembrare che niente dovrebbe impedire al partito di maggioranza di perseguire un programma governativo di legislatura. Poiché d'altro canto il partito di maggioranza governa quasi sempre in coalizione, e poiché deve fare i conti con l'opposizione permanente di un partito che si definisce comunista e marxista, potrebbe ad altri sembrare che la continuità di maggioranze numeriche di governo non sia sufficiente a garantire una continuità legislativa, e che insomma tutto ciò tenda a bloccare la produzione delle leggi. Ma un'analisi del comportamento parlamentare rivela un quadro che a tutta prima mal si adatta ai due scenari. In un recente saggio pubblicato su questa rivista, Franco Cazzola ha per esempio dimostrato che esistono, almeno in termini quantitativi, notevoli «convergenze» tra maggioranza e opposizione comunista, dato che gran gran parte della legislazione di governo viene approvata col consenso di quest'ultima. Come interpretare questo comportamento? Significa forse che il Parlamento ha ormai adottato un modello di comportamento «consociativo», come migliore via di uscita dai pericoli sempre vivi di un confronto tra le sottoculture marxista e cattolica? La risposta, come Cazzola e altri ben dicono, dipende in buona parte dalla qualità di ciò che il Parlamento è in grado di produrre, e poiché l'ambito delle «nondecisioni» abbraccia le materie piú importanti e scottanti, siamo ben lungi dal poter parlare in maniera definitiva di convergenze consociative.
LINGUAGGIO POLITICO E SOCIOLOGICO
Authors: Bartolini Stefano
Published: May 2019

Introduzione

Lo sviluppo e I'arricchimento del linguaggio specialistico è una precondizione per l'avanzamento di ogni disciplina. Le enciclopedie, i dizionari e i' manuali hanno sempre rappresentato tappe di grande importanza in questo processo e il loro sviluppo è un po' 10 sviluppo della specializzazione scientifica e della frammentazione del-l'unità culturale del mondo classico e medievale. Le grandi enciclopedie del passato rappresentavano inventari delle conoscenze umane di un'epoca. Lo stesso significato di «enciclopedia» - ciclo completo della cultura - implica l'idea di un ordine, di un principio o sistema comprensivo in cui tutte le conoscenze si disponevano in rapporti precisi di coordinazione e subordinazione. Oggi questa unità culturale non è piú scientificamente perseguibile e le moderne Enciclopedie Universali costituiscono solo strumenti di divulgazione. A livello scientifico esse vengono sostituite da enciclopedie specialistiche che si concentrano su una o phú discipline affini.

Allo stesso modo, i tradizionali dizionari lessicali non sono piú in grado di comprendere unitariamente 10 sviluppo del linguaggio, non tanto nella sua dimensione quantitativa, ma, piuttosto, in quella qualitativa, cioe in relazione alla crescente differenziazione tra il linguaggio comune e una serie sempre piú numerosa di linguaggi specializzati. Ciò ha condotto allo sviluppo di dizionari che raccolgono il linguaggio tecnico di discipline particolari. Partendo, probabilmente, dai dizionari filosofici e da quelli concernenti le scienze mediche e naturali, si è arrivati infine ai dizionari concernenti scienze recentemente salite alla ribalta, come è il caso della sociologia e della scienza politica. La funzione primaria dei dizionari è comunque rimasta la stessa; diffondere il linguaggio cercando di favorire un uso univoco dei suoi segni e nello stesso tempo aiutarne lo sviluppo.
STRUTTURA DEL POTERE E OUTPUTS DECISIONALI NELLA COMUNITÀ LOCALE
Authors: Goio Franco
Published: May 2019

Introduzione

Da tempo la scienza politica ha fatto dei sistemi politici locali uno dei suoi principali oggetti di indagine, La tradizione è specialmente sviluppata negli Stati Uniti, dove la politica locale costituisce un'area tematica dai contorni ben precisi e relativamente autonoma. Tra gli accostamenti identificabili all'interno del Hlone generale, due spiccano per l'ingente letteratura prodotta, i risultati ottenuti e i dibattiti che ne sono nati: l'accostamento al potere e l'accostamento alla linea politica.

L'accostamento al potere (power approach) è inteso a rilevare empiricarnente la distribuzione del potere nelle comunità locali. Esso si serve eli tecniche diverse, in particolare il metodo « reputazionale » che prevede il ricorso al giudizio di osservatori in loco giudicati particolarmente competenti; e il metodo « decisionale » consistente nell'accertamento diretto dell'influenza esercitata dagli attori privati e pubblici partecipanti al processo di decisione. Sono note le risultanze cui hanno portato le due metodologie e le dispute in merito ai lora efletti distorcenti. Il metodo reputazionale è stato accusato di consentire solamente rilevazioni indirette del potere e di predeterrninare i risultati in senso elitistico; il metodo decisionale di escludere dal campo dell'indagine i rapporti di potere che non ernergono direttamente dal processo decisionale pur condizionan dolo (non-decisioni) e di predeterrninare i risultati in senso pluralistico. La controversia è ancora aperta, nonostante molti autori siano intervenuti in vista di un suo superamento o, almeno, di una sua sdramrnatizzazione.
INSEDIAMENTO SUBCULTURALE E DISTRIBUZIONE DEI SUFFRAGI IN ITALIA
Authors: Bartolini Barbara
Published: May 2019

Introduzione

Le previsioni elettorali della primavera '76 davano per certo un grosso calo della DC e non escludevano il « sorpasso » dei comunisti. Confrontando a caldo i risultati con questo « scenario », è stata naturale la tendenza a sottovalutare i mutamenti introdotti dall'ultima tornata elettorale. Essa tuttavia costituisce, in un'ottica di lungo periodo, un momento di svolta. Quanto meno non si è confermata la stabilità che l'elettorato italiano aveva esibito dal '53 al '72. Stabilità che peraltro non escludeva che all'interno degli schieramenti si verificassero fenomeni dinamici importanti come la tendenza del PCI a prevalere all'interno della sinistra e quella del MSI a prevalere all'interno della destra. Gli incrementi comunisti però, come mostra la tabella 1, sono fino al '72 abbastanza limitati: 8,2 punti percentuali nell'arco di sette elezioni con un « gradino » massimo di 2,6 punti nel '63 rispetto al '58. Dal '72 al '76 invece il PCI aumenta di ben 7,3 punti, mentre l'incremento della sinistra non comunista nel suo insieme è in proporzione molto piccolo (0,7 punti percentuali). L'espansione dell'area di sinistra è quindi quasi totalmente attribuibile al PCI, che oltre a una grossa quota del voto giovanile ha probabilmente conquistato anche un certo numero di ex-elettori del centro e della destra.
CRISI DELLA DC E EVOLUZIONE DEL SISTEMA POLITICO
Authors: Pasquino Gianfranco
Published: May 2019

Introduzione

Nel momento in cui la crisi della Democrazia Cristiana è diventata in maniera lampante il problema principale dell'evoluzione del sistema politico italiano, e da piú parti si levano inviti e si avanzano suggerimenti per una «rifondazione» del partito, è stato giocoforza accorgersi che, al di là di pamphlets giornalistici e analisi di parte, il materiale disponibile su questo partito, sulla sua natura e struttura interna, sui suoi legami con le organizzazioni fiancheggiatrici in Italia e all'estero, sul suo ruolo, è nettamente insufficiente. Nonostante la sua grande e evidente importanza lungo tutti i trent'anni di vita della Repubblica, la Democrazia Cristiana non ha attratto in quantità adeguata l'attenzione degli studiosi, né italiani né stranieri (che, per lo piú, le hanno preferito il PCI) cosicché le analisi esplicitamente dedicatele o sono rapidamente invecchiate o, se recenti, hanno natura giornalistica e non sistematica o, infine, rappresentano attacchi polemici e sfoghi di militanti delusi Resta che le conoscenze attuali sono inadeguate a qualsiasi compito si voglia attendere: ad una rifondazione in senso popolar-progressista di un partito interclassista, alla creazione di un partito conservatore adatto ad una democrazia industriale, ad un recupero di posizioni perdute, alla rottura del blocco di potere coagulato intorno ad essa, senza lo slittamento in senso ieazionario di vasti settori del suo elettorato, oppure infine, alla «semplice» comprensione delle alternative possibili di evoluzione del sistema politico.
“It is alive!” Evidence for animacy effects in semantic categorization and lexical decision
Authors: Bonin Patrick , Gelin Margaux , Dioux Vivien , Méot Alain
Published: May 2019

Animacy is one of the basic semantic features of word meaning and influences perceptual and episodic memory processes. However, evidence that this variable also influences lexicosemantic processing is mixed. As animacy is a semantic variable thought to have evolutionary roots, we first examined its influence in a semantic categorization task that did not make the animacy dimension salient, namely, concrete-abstract categorization. Animates were categorized faster (and more accurately) than inanimates. We then assessed the influence of animacy in two lexical decision experiments. In Experiment 2, we mostly used legal nonwords, whereas in Experiment 3, we varied the context of the nonwords across participants in such a way that the discriminability between words and nonwords was either high or low. Animates yielded faster decision times than inanimates when legal nonwords were used (Experiment 2) and when the discriminability between words and nonwords was low (i.e., “difficult nonwords” in Experiment 3), but the difference between the two types of words was not reliable when discriminability was high (e.g., illegal strings of letters, i.e., “easy nonwords” in Experiment 3). The findings suggest that animacy is a core meaning-related dimension that influences a large number of processes involved in perception, episodic memory, and semantic memory.
Photometry of the Cometary Atmosphere: A Review
Authors: Vanysek V
Published: May 2019

Photometry and polarimetry of the cometary heads still constitute one of the most important sources of information about the physical processes in comets. For instance, most of the present estimates of molecular lifetimes are based on the observed distribution of molecules in the cometary head and the assumption of a particular kinematical behaviour of the matter in the cometary atmospheres.

The study of kinematics and dynamics of cometary heads and tails has been based upon the analysis of the forms and apparent motions of well-defined envelopes, halos, knots in tails and streams. Direct inspection of a large number of photographs (or drawings from the last century) of several bright comets demonstrates that the cometary head is generally a complicated object. The heads consist of nearly circular diffuse patterns with superposition of different features, particularly of curved streams. This is illustrated by the Atlas of the Cometary Forms compiled by Rahe, Donn and Wurm (1970).
Photoelectric Photometry of Comet Kohoutek (1973f)
Authors: Kohoutek Lubos
Published: May 2019

Comet Kohoutek (1973f) has been observed with the 50 cm (f/15) reflecting telescope of the European Southern Observatory, La Silla, Chile, on fourteen nights between January 16 and 30, when the heliocentric and geocentric distances of the comet were r=0 66 - 1 00 A. U and Δ =0 81 - 0.96 A. U. , respectively The 40″ and 80″ diaphragms were used for the photometry of the cometary head (EMI 6256 A photomultiplier) in the UBV system and with six interference filters: CN 3884 Å, CO+ 4267 Å, C2 4737 Å, C2 5172 Å, cont. 5300 Å and Na 5893 Å.

The atmospheric conditions were good but the accuracy of our observations was lower than usual due to large extinction (air mass 25 to 43) and twilight. The mean error of one measurement of log F in all but Na 5893 Å filters can be estimated at ±0.02, whereas the accuracy through the Na filter was substantially lower
Review of Cometary Spectra
Authors: Herbig G. H.
Published: May 2019

Those investigators who have been active in cometary studies for a long time must by now have detected in their midst a number of interlopers from outside the solar system. As one of these newcomers from a far-off field of astronomy, who cannot possibly claim any expertise on comets, I feel compelled to account for the presence of stellar and interstellar astronomers in this arena. The reason is that some of us believe that the comets represent a sample of relatively unprocessed material from the early solar system, from which we may be able to learn something not only of the young sun and planets, but also something about the material of the parent interstellar cloud plus any fresher interstellar material that the cometary nuclei have been able to accrete over the past 4.6 billion years.
Spectroscopic Observations of Comet Kohoutek (1973f)
Authors: Kohoutek Lubos , Rahe Jurgen
Published: May 2019

Between January 5 and January 15, 1974, nine coudé spectrograms of Comet Kohoutek (1973f) were obtained with the ESO 152-cm telescope in La Silla, Chile. The emulsion is Kodak IIa-0 (3 plates) and Kodak 103a-F (6 plates), the dispersion is 20.2 Å/mm. The useful spectral range extends from about 3500 Å to about 5000 Å (Kodak IIa-0 plates) and from about 4500 Å to about 6700 Å (Kodak 103a-F plates). The original scale was 4.55 arc sec/mm on the slit, and the full length of the slit was about 3 arc minutes. 1 mm on the plates corresponds to 66.5 arc sec, or about 3.9-4 4x104 km at the Comet projected on the plane of the sky. The slit was always centered on the image of the Comet, and except for plate No. 1436, was oriented along the radius vector. A field rotator was used which dimished the stellar light by about 30 %.
Spectroscopic Observations of Comet Kohoutek (1973f) II
Authors: Benvenuti Piero
Published: May 2019

Systematic spectroscopic observations of comet Kohoutek (1973f) were scheduled at the Asiago Astrophysical Observatory, starting from the end of October. The nebular spectrograph for the newtonian focus of the 122 cm reflector was selected as main instrument for this research. This spectrograph, described by Bertola (1970), is followed by a WL-30677 image tube and it is particularly designed for extended objects of low surface brightness. Two gratings were used giving a dispersion in the first order of 125 Å mm-1 and 240 Å mm-1 respectively. The scale normal to the dispersion is 127 arcsec mm-1 and the full length of the slit is 8 arcmin.
Radio Detection of H2O in Comet Bradfield (1974b)
Authors: Jackson W. M. , Clark T , Donn B.
Published: May 2019

The present authors (Clark et al, 1971) previously attempted to detect the 1.35 cm microwave line of water in Comet Bennett (1969i) using the 26 m Maryland Point radio telescope of the Naval Research Laboratory. An upper limit for the H2O column density of 1017 molec/cm2 was obtained assuming the rotational levels were in thermal equilibrium, A more recent search in Comet Kohoutek using the 37 m radio telescope of the Haystack Observatory with a low noise traveling wave maser preamplifier was also unsuccessful. In this comet the identification of H2O+ in the visible spectrum gave strong support to the idea of water as a major parent molecule. The radio detection of HCN (Heubner et al, 1974) and CH3CH (Uhlich and Conklin, 1974) in Comet Kohoutek suggested that the attempt to detect H2O should be repeated in a suitable comet.
On the Cometary Hydrogen Coma and Far UV Emission
Authors: Keller H. U.
Published: May 2019

Comet Tago-Sato-Kosaka (1969 IX, hereafter TSK) was the first medium bright comet passing by in the era of ultraviolet satellites. The Orbiting Astronomical Observatory (OAO-2), observed in January 1970 the strong Lyman alpha signal at 1216 A which led to the first detection of cometary hydrogen. The peak signal in the photometer field-of-view (FOV) of 10′ diameter was about 70 kR (Code et. al , 1970) The resonance scattering emission of hydrogen was optically thick in the central part of the coma. A rocket experiment of Jenkins and Wingert (1972) using an objective grating spectrograph confirmed the OAO-2 observations Later in Spring 1970 comet Bennett (1970 II) was observed in Lα by OAO-2 and by two photometers onboard the Orbiting Heophysical Observatory (0G0-5) (Bertaux and Blamont, 1970; Keller and Thomas, 1973).
The Gas Production Rate of Comet Bennett
Authors: Lillie C. F , Keller H. U.
Published: May 2019

Comet Bennett (1970 II) was observed with the ultraviolet photometers on OAO-2 from April 13.39 to May 13.88, 1970, while its heliocentric distance increased from R = 0.77 to 1.26 a.u. An analysis of the photometer data for the emission features of OH λ 3090 and H λ1216 indicates the production rates of OH and H were 2.0 x 1029 molecule sec-1 and 5.4 x 1029 atom sec-1, respectively, at R = 1 a.u During this period the production rates of H and OH varied as R-2.3 . This is consistent with the assumption that water vaporization controls the production rate of gas in comets at small heliocentric distances.
The Scale Length of OH and CN in Comet Bennett (1970 II)
Authors: Keller H. U. , Lillie C. F
Published: May 2019

Comet Bennett (1970II) was observed with an ultraviolet spectrometer on the OAO-2 spacecraft during April 1970 The instrument consisted of a plane grating, a parabolic mirror, a slit, and a photomultiplier tube. The exit slit provided a 2′ x 8′ rectangular field-of-view and a 23 A bandpass. At this resolution emission features such as OH λ3090 and CN λ3883 were essentially monochromatic. Since the instrument had no entrance slit, movement of the grating produced a shift in the field of view, with 1 arc min of spatial offset corresponding to a 10 A wavelength shift.