bluuebunny/crossref_metadata_2025 huggingface dataset:
Purple Nutsedge (Cyperus rotundus) Control with Imazaquin in Warm-Season Turfgrasses
Authors: Coats G. Euel , Munoz Roni F. , Anderson Doug H. , Heering David C. , Scruggs Jim W.
Published: May 2019

Postemergence applications of imazaquin {2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-3-quinolinecarboxylic acid} controlled higher levels of purple nutsedge (Cyperus rotundusL. # CYPRO) in common bermudagrass [Cynodon dactylon(L.) Pers.] and hybrid bermudagrass (′Tifgreen’ and ‘Tifdwarf′,C. dactylon×C. transvaalensisBurtt-Davy) than monosodium salt of methylarsonic acid (MSMA). Control was better at 560 or 840 g ai/ha of imazaquin than at lower rates. Postemergence applications of imazaquin plus 2240 g ai/ha of MSMA controlled more purple nutsedge than equivalent rates of imazaquin alone. Preemergence applications of imazaquin were not effective. Bermudagrass discoloration was observed in some experiments on turfs mowed at a height of 1.3 cm or less but usually disappeared within 2 to 3 weeks, especially when MSMA was used in combination with imazaquin. No injury was observed on bermudagrasses, zoysiagrass (Zoysia japonicaSteud. ‘Meyer′), St. Augustinegrass [Stenotaphrum secundatum(Walt.) Ktze. ‘Raleigh′], and centipedegrass [Erernochloa ophiuroides(Munro) Hack.] maintained at mowing heights above 1.3 cm.
Heritability of Metribuzin Tolerance in Sweet Potatoes (Ipomoea batatas)
Authors: Harrison Howard F. , Jones Alfred , Dukes Philip D.
Published: May 2019

Twenty-two sweet potato [Ipomoea batatas(L.) Lam.] clones with a wide range in metribuzin [4-amino-6-(1,1-dimethylethyl)-3-(methylthio)-1,2,4-triazin-5(4H)-one] tolerance were used to establish narrow sense heritability estimates (h2) using a greenhouse procedure. The heritability estimates were obtained from simple linear regressions (h2= 2b) of injury rating, shoot fresh weight, and change in shoot fresh weight of offspring against the same responses of parents at metribuzin concentrations of 0, 0.3, and 0.6 ppm in the potting medium and averaged data for the two concentrations. These values ranged from 0.85 to 1.0, indicating that a recurrent mass selection process should be an appropriate approach to developing metribuzin-tolerant cultivars. Several highly tolerant clones were identified.
The Absence of a Role of Absorption, Translocation, or Metabolism in the Selectivity of Picloram and Clopyralid in Two Plant Species
Authors: Hall J. Christopher , Vanden Born William H.
Published: May 2019

Experiments were conducted to determine whether differences in sensitivity of sunflower (Helianthus annuusL.), and rapeseed (Brassica napusL.) to14C-picloram (4-amino-3,5,6-trichloro-2-pyridinecarboxylic acid) and14C-clopyralid (3,6-dichloro-2-pyridinecarboxylic acid) can be attributed to differences in absorption, translocation, or metabolism of the herbicides. Within 24 h, more than 97% of the radioactivity from picloram or clopyralid was absorbed by the foliage of both plant species. Acropetal transport of both herbicides was similar in the two plant species, with approximately 60% or more of the recovered radioactivity from picloram and clopyralid treatments moving acropetally out of the treated leaf 144 h after application. Less than 6% of the14C-label from either herbicide treatment moved basipetally in both species. Therefore, differences in absorption and translocation did not account for intra- or inter-species sensitivity differences to the two herbicides. Significantly more14C-picloram and14C-clopyralid was converted to water-soluble metabolites in rapeseed than in sunflower plants. However, in rapeseed plants, the pattern of metabolism of both herbicides was similar, indicating that the difference between the metabolism of picloram and clopyralid did not account for the sensitivity difference within this species. It appears that only one picloram and clopyralid metabolite was formed in both plant species as determined by TLC. The metabolite of picloram or clopyralid was a water-soluble conjugate that yielded the carboxylic acid amide of the respective herbicide upon ammonolysis.
Resistance of Common Cocklebur (Xanthium strumarium) to the Organic Arsenical Herbicides
Authors: Haigler William E. , Gossett Billy J. , Harris James R. , Toler Joe E.
Published: May 2019

The presence of a common cocklebur (Xanthium strumariumL. # XANST) population resistant to organic arsenical herbicides was confirmed in three adjoining counties of South Carolina's ten-county cotton-growing region, but little evidence of resistance was found in the remaining seven counties. This population was resistant to both disodium salt of methylarsonic acid (DSMA) and monosodium salt of methylarsonic acid (MSMA) but not to herbicides from nine other chemical groups. A much greater level of resistance was apparent in the field than under greenhouse conditions and larger plants were more resistant than small plants.
Wild Oat (Avena fatua) and Spring Barley (Hordeum vulgare) Growth and Development in Monoculture and Mixed Culture
Authors: Morishita Don W. , Thill Donald C.
Published: May 2019

Barley (Hordeum vulgareL. ‘Advance’) and wild oat (Avena fatuaL. # AVEFA) were grown in the field in monoculture and mixed culture (additively) to compare their seasonal growth and development. Barley and wild oat tiller and tiller head production were reduced by the interference (higher density) of the other species. Plant height of either species was not affected by interference of the other. Wild oat biomass was reduced more and at an earlier growth stage (two to three tillers) than was barley biomass (heading) in mixed culture. Barley and wild oat grown in monoculture had similar total plant nitrogen content throughput the growing season. Gas exchange and water potential of barley and wild oat in monoculture and mixed culture were similar. All measurements indicated that barley and wild oat grown in monoculture had growth and development patterns that were similar. In mixed culture, however, barley was more competitive with wild oat than wild oat was with barley. Wild oat reduced barley yield component quality and grain yield.
Sorption of Metribuzin in Surface and Subsurface Soils of the Mississippi Delta Region
Authors: Harper Sidney S.
Published: May 2019

Sorption and desorption of metribuzin [4-amino-6-(1,1-dimethylethyl)-3-(methylthio)-1,2,4-triazin-5(4H)-one] were measured in Dundee silty clay loam surface and subsurface soils. Soil samples were taken from a profile that had been divided into six sections from the surface to a depth of 175 cm. Metribuzin sorbed weakly to all soils from this profile with Freundlich distribution constants ranging from 0.78 to 1.34 μmole/kg. Soils from lower depths of the profile having higher pH (>7.0) and clay contents (>35%) sorbed significantly more metribuzin than the lower clay content, higher organic matter surface soils. Stepwise regression of the distribution constants against the variables pH, organic matter, clay content, and sand content showed that clay was the single best predictor, with sorption increasing as clay content increased (r2=0.750). The combination of two variables most related to sorption was clay and pH (r2=0.860, P= 0.15). Organic matter was not one of the primary variables related to sorption. Metribuzin was easily desorbed in all soils with less than 5% of the originally applied metribuzin remaining after three desorption treatments. This would indicate little tendency for irreversible sorption. This study demonstrates that soil properties within a profile determine sorption and, subsequently, movement of metribuzin.
Spread of Paraffinic Oil on Leaf Surfaces of Johnsongrass (Sorghum halepense)
Authors: McWhorter Chester G. , Barrentine William L.
Published: May 2019

Paraffinic oil applied at 2.3, 4.7, and 9.3 L/ha to the surface of johnsongrass [Sorghum halepense(L.) Pers. # SORHA] leaves spread to provide complete coverage of the leaf surface. Soybean oil applied at the same volumes provided only 30 to 50% coverage of leaf surfaces. Water at 187 L/ha that contained 1.25% paraffinic oil adjuvant provided only about 30% coverage because spray droplets did not spread appreciably. Spread coefficients obtained when five different oil-soluble herbicides were applied to leaf surfaces in paraffinic oil were more than 100 times greater than when applied in water alone. Higher spread coefficients were obtained when paraffinic oil contained herbicides than when paraffinic oil was applied alone. Spread coefficients were also much greater for paraffinic oil alone than for soybean oil with or without herbicides. Stomata on johnsongrass leaves were distorted by paraffinic oil, suggesting that leaf surface wax was dissolved and this might be a mode of entry of herbicide into johnsongrass when applied in paraffinic oil. Stomata were unaffected by soybean oil or by water sprays that contained 1.25% soybean oil adjuvant or paraffinic oil adjuvant.
Herbicidal Properties of Metabolites from Several Genera of Soil Microorganisms
Authors: Mishra Saroj K. , Whitenack Curt J. , Putnam Alan R.
Published: May 2019

Metabolites from 906 microbial isolates were evaluated for herbicidal properties. These included 266 isolates ofStreptomyces, 502 isolates of non-Streptomycesactinomycetes representing 18 genera, 28 unidentified aerobic actinomycetes, 70 fungi, and 40 isolates of eubacteria. Metabolites from 72 isolates significantly inhibited germination of cress seeds. In terms of generic specificity and frequency, about 18% of all theStreptomycesandNocardiopsisisolates and 13% ofActinoplanesisolates were toxic to cress (Lepidium sativumL.) seeds. Among other inhibitors were three isolates ofActinomaduraand one isolate each ofMicromonospora, Micropolyspora, Strep to sporangium, Streptoverticillium, andBacillus, and two isolates of unidentified actinomycetes. The toxigenic fungi included two isolates ofPenicilliumand one isolate each ofAspergillus, Scopulariopsis, andPaecilomycesspecies. About half the isolates toxic to cress were toxic to barnyardgrass (Echinochloa crus-galliL. Beauv. # ECHCG) seeds. of the isolates found effective in the secondary screening on the potted weeds, eight belonged to the genusStreptomycesand one was identified asScopulariopsis brumptii. None of the examined isolates ofRhodococcus, Nocardia, Oerskovia, Thermoactinomyces, Thermomonospora, andsix other genera of actinomycetes showed any appreciable toxicity to the seeds of either species.
Uptake and Translocation of Fluazifop in Green Foxtail (Setaria viridis)
Authors: Grafstrom Lester D. , Nalewaja John D.
Published: May 2019

Experiments were conducted on uptake and translocation of butyl ester of14C-fluazifop {(±)-2-[4-[[5-(trifluoromethyl)-2-pyridinyl]oxy]phenoxy] propanoic acid} in green foxtail [Setaria viridis(L.) Beauv. # SETVI]. Absorption of14C-fluazifop reached 67.6% 12 h after treatment with the petroleum oil additive compared to 44.0% when applied alone. Maximum14C-fluazifop absorption detected was 74.2% after 48 h with the oil additive compared to 58.6% after 72 h when applied alone. Translocation of14C-fluazifop was greater when applied with the oil additive than alone, but translocation did not increase after 12 h. Absorption and translocation of14C-fluazifop by green foxtail was greater when applied with the oil additive than alone in all environments. The oil additive overcame the reduced absorption of14C-fluazifop applied alone with low temperature (20 C), relative humidity (40%), and soil fertility (0.25× strength Hoagland's solution), but not the reduced absorption and translocation with an increase in stress to −10 bars.14C-fluazifop lost as vapors from the treated green foxtail leaf was 4.1% when applied alone compared to 0.6% when applied with an oil additive.
Seedling Growth of Soybeans (Glycine max) and Selected Weeds
Authors: Monks David W. , Oliver Lawrence R. , Bozsa Robert C.
Published: May 2019

Seedling growth of soybean[Glycine max(L.) Merr. ‘Forrest’], common cocklebur (Xanthium strumariumL. # XANST), and tall morningglory[Ipomoea purpurea(L.) Roth. # PHBPU] was compared in field studies. Root growth was determined by measuring roots restricted to the inside of a permeable membrane that contained no soil. Leaf area duration and net assimilation rate between 4 and 9 weeks were greatest for common cocklebur compared to the other species. At 9 weeks, shoot and root dry weight and leaf area were greatest for common cocklebur compared to soybean and tall morningglory. Relative growth rate of common cocklebur roots was greater than the other species between 4 and 9 weeks. Tall morningglory had greater shoot length or height at 4 and 9 weeks and greater shoot or height elongation rate between 2 and 4 weeks, and 4 and 9 weeks than the other species.
Growth, Gas Exchange, and Germination of Several Jointed Goatgrass (Aegilops cylindrica) Accessions
Authors: Gealy David R.
Published: May 2019

Growth, development, and germination among jointed goatgrass (Aegilops cylindricaHost. # AEGCY) accessions collected from nine western states were not consistently different in field plots near Pullman, WA, or in the greenhouse. Germination percentage and rate of spikelet germination of all accessions produced in the field and greenhouse were consistently high, averaging about 64% and 5.2 (on a unitless scale of 0 to 7), respectively. The Montana accession germinated consistently less than the others. In a separate greenhouse study comparing only the accessions from Colorado and Nebraska, the accession from Colorado averaged 18, 16, and 15% greater net photosynthesis rate (Pn), transpiration rate (E), and stomatal density, respectively, and 21% lower diffusive resistance (rl) than did the accession from Nebraska. However, growth parameters of the Nebraska accession averaged 7 to 35% greater than for the Colorado accession. Overall, the germination, growth, CO2fixation, and water use among accessions appeared to be similar when jointed goatgrass was grown under Pacific Northwest conditions.
Proso Millet (Panicum miliaceum) Control in Corn (Zea mays) by Postemergence-Directed Herbicides
Authors: Fawcett James A. , Harvey Robert G.
Published: May 2019

Proso millet (Panicum miliaceumL. # PANMI) was controlled in corn (Zea maysL. ‘Pioneer 3747’) with postemergence-directed herbicides applied following a standard preplant-incorporated application of butylate[S-ethylbis(2-methylpropyl)carbamothioate] plus dichlormid (2,2-dichloro-N,N-di-2-propenylacetamide) plus cyanazine {2-[[4-chloro-6-(ethylamino)-1,3,5-triazin-2-yl]amino]-2-methylpropanenitrile}. Postemergence-directed applications of ametryn [N-ethyl-N′-(1-methylethyl)-6-(methylthio)-1,3,5-triazine-2,4-diamine], cloproxydim {(E,E)-2-[1-[[(3-chloro-2-propenyl)oxy]imino]butyl]-5-[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one}, butyl ester of fluazifop {(±)-2-[4-[[5-(trifluoromethyl)-2-pyridinyl]oxy]phenoxy] propanoic acid}, butyl ester of fluazifop-p {(R)-2-[4-[[5-(trifluoromethyl)-2-pyridinyl]oxy]phenoxy] propanoic acid}, glyphosate [N-(phosphonomethyl)glycine], methyl ester of haloxyfop {2-[4-[[3-chloro-5-(trifluoromethyl)-2-pyridinyl]oxy]phenoxy]propanoic acid}, and sethoxydim {2-[1-(ethoxyimino)butyl]-5-[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one} in 40-cm-tall corn gave greater than 90% control of 5- to 15-cm-tall proso millet while causing little or no corn injury at selected rates. Season-long proso millet control was obtained with sethoxydim at rates as low as 56 g ai/ha with no visible corn injury. Unacceptable injury to 40-cm-tall corn occurred with all but the lowest rate of sethoxydim (56 g ai/ha) when a crop oil concentrate was used. Sethoxydim applied as a directed spray at rates up to 110 g ai/ha plus 1.25% (v/v) crop oil concentrate did not injure 60-cm-tall corn.
The Influence of Herbicides on the Growth and Yield of Muskmelons (Cucumis melo)
Authors: Motsenbocker Carl E. , Bonanno A. Richard
Published: May 2019

Three herbicide treatments were evaluated for use under clear polyethylene mulch and three types of row covers (spunbonded polyester, double-slitted polyethylene, and perforated polyethylene). Treatments included combinations of bensulide {O,O-bis(1-methylethyl)-S-[2-[(phenylsulfonyl)amino]ethyl]phosphorodithioate} and naptalam {2-[(1-naphthalenylamino)carbonyl]benzoic acid}, and cinmethylin {exo-1-methyl-4-(1-methylethyl)-2-[(2-methylphenyl)methoxy]-7-oxabicyclo [2.2.1] heptane} alone and in combination with naptalam. In 1985 and 1986, all herbicide treatments controlled more than 95% of carpetweed (Mollugo verticillataL. # MOLVE) and large crabgrass [Digitaria sanguinalis(L.) Scop. # DIGSA], except for the combination of bensulide plus naptalam in 1986, which controlled only 73 to 85% of these weeds. In both years, all herbicide treatments reduced crop vigor at 3 weeks but not at 7 weeks after transplanting. Total yield was not different with any of the herbicide treatments in 1985 and 1986. However, in 1986, yields were greater from the bensulide plus naptalam treatment than for the weed-free control. Herbicide treatment did not affect early yields in 1985, but the bensulide plus naptalam treatment was greater than all others in 1986. The use of row covers did not increase herbicide-induced crop injury over that of clear mulch alone. Greenhouse studies indicated that soil-applied cinmethylin reduced muskmelon root and shoot weight. Foliar applications reduced muskmelon shoot weight.
Response of Canada Thistle (Cirsium arvense) and Birdsfoot Trefoil (Lotus corniculatus) to Bentazon
Authors: Boerboom Chris M. , Wyse Donald L.
Published: May 2019

Bentazon [3-(1-methylethyl)-(1H)-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide] was evaluated for Canada thistle[Cirsium arvense(L.) Scop. # CIRAR] control and birdsfoot trefoil (Lotus corniculatusL. ‘Norcen’) tolerance. Bentazon applied in split applications controlled more Canada thistle than a single application of equal rate in both greenhouse and field studies. Bentazon applied four times reduced the level of total nonstructural carbohydrates (TNC) in the roots of both greenhouse- and field-grown Canada thistle and increased birdsfoot trefoil injury more than bentazon applied in a single application of equal rate. All bentazon treatments caused unacceptable injury when birdsfoot trefoil was grown for seed.
Thiameturon Phytotoxicity to Kochia (Kochia scoparia)
Authors: Nalewaja John D. , Adamczewski Kazimierz A.
Published: May 2019

The methyl ester of thiameturon {3-[[[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino] carbonyl] amino] sulfonyl]-2-thiophencarboxylic acid} toxicity to kochia [Kochia scoparia(L.) Schrad. # KCHSC] increased with surfactant concentration in the spray to 0.25% (v/v). High soil nitrogen fertility (165 ppm) enhanced kochia susceptibility to thiameturon compared to low nitrogen fertility (65 ppm). Nitrogen plus surfactant in the spray only partially overcame the effect of low soil nitrogen but did enhance thiameturon toxicity to kochia at all fertilities. Petroleum oil plus surfactant enhanced thiameturon so that kochia fresh weight reduction was similar regardless of soil fertility. Thiameturon toxicity to kochia generally increased with an increase in temperature regardless of relative humidity (RH) or adjuvants. An RH of 90 to 95% enhanced thiameturon toxicity to kochia regardless of temperature or adjuvants, except for petroleum oil plus surfactant with the low (10:8 C day:night) temperature regime. A simulated rain of 2 mm within 24 h after treatment reduced thiameturon toxicity to kochia. Drought stress (≤25% of field capacity) after thiameturon application reduced toxicity regardless of spray additives. The results of the various experiments indicated that thiameturon phytotoxicity would be greatest to kochia growing with high temperature and high RH, adequate soil moisture and nitrogen fertility, and when applied with petroleum oil plus surfactant.
Growth and Water Relations of Cotton (Gossypium hirsutum), Spurred Anoda (Anoda cristata), and Velvetleaf (Abutilon theophrasti) During Simulated Drought and Recovery
Authors: Patterson David T.
Published: May 2019

Cotton (Gossypium hirsutumL. ‘Coker 315’), spurred anoda [Anoda cristata(L.) Schlecht. # ANVCR], and velvetleaf (Abutilon theophrastiMedik. # ABUTH) were grown in controlled-environment chambers at 29/23 C day/night temperature and 1000 μE·m–2·s–1photosynthetic photon flux density (PPFD). Groups of plants were subjected to water stress by withholding water for 8 days, beginning at 27 days after planting. Cotton reached a lower leaf water potential than spurred anoda and velvetleaf following 8 days of withholding water. Following the drought, plants were rewatered for a 6-day recovery period. Water stress reduced plant height, leaf number, leaf area, total dry weight, stomatal conductance, transpiration, net assimilation rate, and leaf area duration in all species, in comparison with well-watered controls. Water stress decreased partitioning of plant biomass into leaves and increased partitioning into roots. Following rewatering, stomatal conductance and transpiration rates of previously stressed plants recovered to control levels within 28 h. Net assimilation rates of previously stressed spurred anoda also recovered to control levels. After 6 days of recovery, total dry weights and leaf areas of previously stressed plants of all three species remained below those of control plants. The overall effect of the drought and water stress was to delay the time at which spurred anoda and velvetleaf equaled or surpassed cotton in dry weight and leaf area, suggesting that drought early in the growing season under field conditions might increase the competitiveness of cotton relative to the two weeds.
Propanil Plus Methyl Parathion on Rice (Oryza sativa)
Authors: Wills Gene D. , Street Joe E.
Published: May 2019

Effects of propanil [N-(3,4-dichlorophenyl)propanamide] applied to three- to four-leaf rice (Oryza sativaL.) 1 or 7 days before, after, or tank mixed with methyl parathion (O,O-dimethyl-O-4-nitrophenyl phosphorothioate) were determined under different environmental conditions. Field experiments determined the effect on yield of drill-seeded rice, ‘Labelle’ for two planting dates in 1982 and ‘Lemont’ for one planting date in 1986. Treatments were applied at sunrise and at noon. Growth chamber and greenhouse experiments determined the effects of temperature, relative humidity (RH), and soil moisture on response of Labelle rice. In all experiments, propanil, both alone and with methyl parathion, resulted in 20 to 30% leaf burn during the first week after treatment with rapid recovery to less than 10% injury after 3 to 4 weeks. In field experiments, yields were not reduced in the treated rice below that in the untreated controls. In controlled-environment experiments, rice was not injured by propanil plus methyl parathion more than by propanil alone after 2 to 4 weeks. Both treated and untreated rice were injured more by the environmental conditions of high (40 C) temperature, low (40%) RH, and low (near the wilting point) soil moisture than by low (30 C) temperature, high (100%) RH, and flooded soil.
Consecutive Annual Applications of Alachlor and Metolachlor to Continuous No-Till Corn (Zea mays)
Authors: Doub J. Peyton , Wilson Henry P. , Hines Thomas E. , Hatzios Kriton K.
Published: May 2019

Consecutive annual applications of alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide] and metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide] were made to continuous no-till corn (Zea maysL. ‘Pioneer 3184’ in 1982 and 1983, ‘Pioneer 3744’ in 1984, and ‘Pioneer 3378’ in 1985 to 1987). In a 5-yr study, control of the dominant annual grass species, large crabgrass [Digitaria sanguinalis(L.) Scop. # DIGSA], by alachlor declined to less than 50% by the fifth year. Control of large crabgrass by metolachlor remained greater than 80% throughout the study but metolachlor allowed the establishment of a greater fall panicum (Panicum dichotomiflorumMichx. # PANDI) population in this and an additional 3-yr study than in chloroacetamide-free checks. In the 3-yr study in which giant foxtail (Setaria faberiHerrm. # SETFA) was dominant, annual applications of metolachlor and a microencapsulated formulation of alachlor provided better control in the second year than the emulsifiable concentrate formulation of alachlor, but formulation differences diminished in the third year.
Control of White Locoweed (Oxytropis sericea)
Authors: Ralphs Michael H. , Mickelsen Larry V. , Turner David L. , Nielsen Darwin B.
Published: May 2019

Several herbicides were evaluated for control of white locoweed (Oxytropis sericeaNutt. T & G # OXRMA) and changes in botanical composition on two sites on high-elevation rangeland. White locoweed was more abundant and its population more stable on the rocky subalpine wind-swept ridge site than on the subalpine loam site. Picloram (4-amino-3,5,6-trichloro-2-pyridinecarboxylic acid) at 0.6 and 1.1 kg ae/ha, and 2,4-D [(2,4-dichlorophenoxy)acetic acid] at 2.2 and 4.5 kg ae/ha eliminated white locoweed on the subalpine loam site, although the population on this site declined naturally. Clopyralid (3,6-dichloro-2-pyridinecarboxylic acid) was the most effective herbicide on the subalpine wind-swept site. Clopyralid at 0.3 and 0.6 kg ae/ha, dicamba (3,6-dichloro-2-methoxybenzoic acid) at 2.2 kg ae/ha, and 2,4-D at 1.1 kg ae/ha plus clopyralid or picloram at 0.3 kg/ha killed all white locoweed plants. Lower rates of clopyralid (0.1 kg/ha), dicamba (0.6 and 1.1 kg/ha), 2,4-D (2.2 and 4.5 kg/ha), and triclopyr {[(3,5,6-trichloro-2~pyridinyl)oxy] acetic aicid)} (0.6, 1.1, and 2.2 kg ae/ha) killed 45 to 84% of white locoweed plants. Grass cover increased on most treated areas where white locoweed, forbs, and sagebrush declined. Cattle consumption of white locoweed declined following application of 2,4-D.
Quackgrass (Agropyron repens) Control in Potatoes (Solanum tuberosum) by Fluazifop
Authors: Ivany Jerry A.
Published: May 2019

In greenhouse and field studies, fluazifop {(±)-2-[4-[[5-(trifluoromethyl)-2-pyridinyl]oxy]phenoxy] propanoic acid} controlled quackgrass [Agropyron repens(Beauv.) # AGRRE] in potato (Solanum tuberosumL. ‘Russet Burbank’). Quackgrass control with fluazifop at 0.25 and 0.5 kg ai/ha in the greenhouse was greatest with application at the two-leaf stage compared with the four-and six-leaf stages. Control was not affected by rhizome length, with similar control obtained of plants grown from 2- and 10-node rhizome pieces. Removal of quackgrass shoots at 6 or 24 h after treatment resulted in decreased control at application rates of 0.25 and 0.5 kg/ha. Fluazifop at 0.5 kg/ha controlled quackgrass treated at the four-leaf stage. The active enantiomer of fluazifop at half the rate of the racemic mixture controlled the quackgrass to the same extent. Fluazifop did not affect potato yield.
Effect of Environment and Adjuvants on Asulam Phytotoxicity
Authors: Nalewaja John D. , Woznica Zenon
Published: May 2019

Experiments were conducted to determine the influence of various factors on asulam {methyl[(4-aminophenyl)sulfonyl] carbamate} toxicity to flax (Linum usitatissimumL.) and wild oats (Avena fatuaL. # AVEFA). Asulam toxicity to both flax and wild oats generally increased as temperature, humidity, and soil moisture increased after treatment. Octoxynol {α-[p-1,1,3,3-tetramethyl butyl phenyl]-ω-hydroxypoly(oxyethylene)} in the spray solution increased asulam toxicity to both species in all environments. Octoxynol and trimethylenonypolyethoxyethanol (WK) enhanced asulam toxicity more than other adjuvants evaluated. Asulam toxicity to both flax and wild oats increased as octoxynol concentration in the spray increased. Flax tolerance to asulam generally increased with flax height at treatment. ‘Flor’ flax was the most asulam susceptible of six cultivars evaluated. A 2-mm simulated rainfall within 3 or 6 h after asulam treatment reduced toxicity to wild oats and flax, respectively.
Tolerance of Rice (Oryza sativa) to Acifluorfen and Triclopyr Applied Alone or in Mixtures by Propanil
Authors: Smith Roy J.
Published: May 2019

Acifluorfen {5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid} applied alone and in mixtures with propanil [N-(3,4-dichlorophenyl)propanamide] reduced rough grain yield of rice (Oryza sativaL. ‘Lebonnet’ or ‘Bond’) by 7% when applied at the late-booting or heading growth stages, averaged over several rates of application. Earlier applications did not reduce rice yield. The highest rate (0.6 kg ai/ha) of acifluorfen alone and in mixtures with propanil at 3.4 kg ai/ha reduced grain yields more than lower rates (0.1 or 0.3 kg ai/ha). Triclopyr {[(3,5,6-trichloro-2-pyridinyl)oxy] acetic acid} alone and in mixtures with propanil reduced rough grain yields of rice by 18% when applied at the late-booting growth stage, averaged over several rates of applications, but did not affect yields when applied at the early-tillering, jointing, or early-booting growth stages. Whole-grain milling yield and germination of rice seed were not affected by acifluorfen or triclopyr alone or in mixtures with propanil, regardless of rate or growth stage of application.
Long-Term Effects of No-tillage in a Winter Wheat (Triticum aestivum)-Sorghum (Sorghum bicolor)-Fallow Rotation
Authors: Wicks Gail A. , Smika Darryl E. , Hergert Gary W.
Published: May 2019

This research was conducted near North Platte, NE, over an 18-yr period to determine the feasibility of using herbicides to replace tillage as the weed control method in a winter wheat (Triticum aestivumL.)-sorghum [Sorghum bicolor(L.) Moench.]-fallow rotation. Five tillage treatments [two tillage and three reduced or no-till treatments] were used on the same plots during the duration of this experiment on a Holdrege silt loam (Typic Argiustolls). Herbicides effectively replaced tillage for weed control. The no-till plots treated with atrazine [6-chloro-N-ethyl-N′-(1-methylethyl)-1,3,5-triazine-2,4-diamine] after wheat harvest had higher sorghum and winter wheat yields, higher crop residue remaining on the soil surface, and lower weed yields than tilled plots. The most difficult weeds to control were volunteer wheat and barnyardgrass [Echinochloa crus-galli(L.) Beauv. # ECHCG]. Soil surface pH decreased over time because of increased use of nitrogen. The pH in nontilled plots was significantly lower than in tilled plots due to lack of soil mixing. Exchangeable calcium was the predominant cation leached from the top 5 cm but showed accumulation between the 5- to 12.5-cm depth. Organic matter content showed little change over time.
Soil Factors and Efficacy of Hexazinone Formulations for Loblolly Pine (Pinus taeda) Release
Authors: Minogue Patrick J. , Zutter Bruce R. , Gjerstad Dean H.
Published: May 2019

Broadcast applications of hexazinone [3-cyclohexyl-6-(dimethylamino)-1-methyl-1,3,5-triazine-2,4(1H,3H)-dione] pellets and foliar sprays were tested at four rates for hardwood control and safety to loblolly pine (Pinus taedaL.) at each of eight study locations differing in soil characteristics. Reduction in the number of hardwoods in the stand (hardwood density reduction) was greater with the pellet on soils with more than 60% sand, while the liquid formulation was most efficacious for finely textured soils. Hardwood density reduction with the pellet was negatively correlated with percent silt, clay, soil organic matter, and cation exchange capacity, and positively correlated with percent sand. With foliar sprays, hardwood density reduction was positively correlated with hexazinone rate and negatively correlated with soil pH. Pine mortality was positively correlated to percent sand with the pellet and negatively correlated to soil pH with broadcast sprays. Regression models incorporating pine height, herbicide rate, soil texture, cation exchange capacity, soil organic matter, and acidity could explain up to 78% of the variation in hardwood density change and 77% of the variation in pine mortality. Selective control of hardwoods in young loblolly pine stands is a function of hexazinone rate, formulation, and various soil factors.
Toxicity and Site of Uptake of Soil-Applied Imazaquin in Yellow and Purple Nutsedges (Cyperus esculentusandC. rotundus)
Authors: Nandihalli Ujjanagouda B. , Bendixen Leo E.
Published: May 2019

Imazaquin {2-(4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl)-3-quinolinecarboxylic acid} site of uptake and toxicity from soil application were investigated in yellow nutsedge (Cyperus esculentusL. #3CYPES) and purple nutsedge (C. rotundusL. # CYPRO). Imazaquin concentrations of 0.1 to 0.5 ppmw inhibited yellow nutsedge shoot emergence completely, while purple nutsedge shoots emerged at the lower concentrations. Herbicide placement above the tuber reduced shoot emergence and shoot and root dry weights of both species more than did placement below the tuber. Increasing herbicide rate increased the number of tuber buds that sprouted. Three-day-old nutsedge propagules absorbed14C-imazaquin from both rhizome shoots and roots and the herbicide moved both acropetally and basipetally in nutsedge propagules.
Duration of Enhanced Soil Degradation of EPTC as Influenced by Herbicide Rotation, Time, and Location
Authors: Bean Brent W. , Roeth Fred W. , Martin Alex R. , Wilson Robert G.
Published: May 2019

Soils did not remain enhanced for EPTC degradation when EPTC was applied in a biennial rotation with cyanazine, cycloate, or alachlor as indicated by laboratory analysis and early-season weed control in the year of EPTC use. Control of late-season weeds was less when EPTC was rotated with alachlor than with a first-time use of EPTC. EPTC degradation remained enhanced in an EPTC-butylate rotation. The reversion rate of soil from an enhanced condition to normality was gradual and varied with location, year, and number of prior EPTC applications. At Clay Center and Scottsbluff, soils reverted to a nonenhanced EPTC degradation rate 18 months after initial EPTC application. At Scottsbluff, soil was not enhanced for EPTC degradation 18 months after the second of two annual EPTC applications. Soil from Clay Center was partially enhanced for EPTC degradation 18 months after the second of two annual EPTC applications but was not enhanced after 30 months.
Atrazine, Bifenox, and Shade Effects on Crownvetch (Coronilla varia) Nodulation and Nodule Activity
Authors: Cardina John , Hartwig Nathan L.
Published: May 2019

Studies were conducted to determine whether photosynthesis-inhibiting herbicides atrazine or bifenox, and shade affect the number, weight, senescence, and N fixation activity of nodules on the roots of the perennial legume crownvetch. Atrazine and bifenox were applied at rates of 2.24 kg ai/ha to shaded and unshaded plots. The shade was varied during the growing season to simulate changing irradiance levels beneath a corn canopy. Atrazine and bifenox treatments reduced nodule number to 13 and 42% of the untreated control, respectively, in 1980, and 18 and 35% in 1981. Shade treatments reduced nodule number to a low of 40% of the control in 1980 and 50% in 1981. Combined effects of herbicides and shade on nodule numbers were more than additive. Nodule fresh weights were reduced an average of 37% by herbicide treatments and 39% by shade treatments. Sloughed nodule numbers decreased in the herbicide and shaded treatments, suggesting that the reduction in nodule numbers was due to fewer nodules being produced. Nodule numbers were reduced a greater percentage by herbicides and shade than was herbage dry matter production. Specific nodule activity (SNA) did not differ in nodules from the atrazine, bifenox, or shade treatments on the six sampling dates in 1980 or on two of three sampling dates in 1981.
Effect of Russian Thistle (Salsola iberica) Interference on Spring Wheat (Triticum aestivum)
Authors: Young Frank L.
Published: May 2019

The effect of Russian thistle density and duration of interference on spring wheat was investigated in two 3-yr field studies. In the density study, the best fit regression equation predicted a loss in spring wheat yield of 0.5, 0.5, and 0.6% in 1983, 1984, and 1985, respectively, for each percent of the total biomass contributed by Russian thistle. In 1985, when rainfall was 46% below normal, the highest weed density produced greater than 70% of the total plant biomass and reduced yields more than 50%. In contrast, in 1984 when rainfall was 65% above normal, the highest weed density produced less than 20% of the total plant biomass and reduced yields 11%. In the duration study, the predicted yield loss was 2.3 and 0.7% for 1983 and 1984, respectively, for each week of interference. In 1985, yield was not significantly reduced until after 6 weeks of interference. In both studies, spikes/m of row had the highest correlation with yield and were affected the most by weed interference.
Outcrossing in Velvetleaf (Abutilon theophrasti)
Authors: Andersen Robert N.
Published: May 2019

Using an accession of velvetleaf having a high degree of purple pigmentation as the male parent made possible the identification of seedlings resulting from controlled or natural crosses. Cross-pollination, even after flowers had opened and anthers had shed pollen, was demonstrated by transmitting pollen manually. Natural outcrossing was demonstrated in the field by growing plants of the purplepigmented accession in close proximity to locally occurring velvetleaf. Insect transmission of pollen was suspected.
Velvetleaf (Abutilon theophrasti) Growth and Development in Conventional and No-Tillage Corn (Zea mays)
Authors: Defelice Michael S. , Witt William W. , Barrett Michael
Published: May 2019

Monoculture velvetleaf had greater dry weight, growth rate, leaf area index, and height than velvetleaf grown in association with conventional or no-tillage corn. Velvetleaf planted 5 weeks after corn had significantly lower dry weight, leaf area index, and height compared to velvedeaf planted at the same time as corn. The combination of interference from corn and delayed planting caused a significant reduction in velvetleaf population at the end of the season, delayed the date of 50% velvetleaf flowering, increased the number of days required for 50% flowering, and reduced the number of capsules per plant. Velvetleaf dry weight/hectare and leaf area index increased as plant population increased. Velvetleaf dry weight, leaf area, capsules, and seed/plant decreased as plant density increased. There were no differences in vegetative or reproductive growth between velvetleaf grown in conventional or no-tillage areas.
Influence of Imazapyr on the Control of Pitted Morningglory (Ipomoea lacunosa) and Johnsongrass (Sorghum halepense) with Chlorimuron, Imazaquin, and Imazethapyr
Authors: Riley Dennis G. , Shaw David R.
Published: May 2019

Field experiments were conducted to evaluate postemergence combinations of imazethapyr, imazquin, or chlorimuron with low rates of imazapyr for Johnsongrass and pitted morningglory control. Imazapyr applied alone at rates up to 4 g ai/ha gave little or no control of either weed species. However, the addition of imazapyr to various rates of imazethapyr or imazaquin synergistically increased both johnsongrass and pitted morningglory control 8 weeks after treatment. The rates of imazethapyr or imazaquin required for significant enhancement of johnsongrass control were higher than those required for pitted morningglory control. No synergistic increases in control of either weed species were noted with mixtures of imazapyr and chlorimuron. Although not synergistic in every case, the mixtures of imazapyr at 4 g/ha with imazethapyr, imazaquin, or chlorimuron gave johnsongrass and pitted morningglory control equal to or better than the next higher rate of these herbicides applied alone. Imazapyr did not increase soybean injury or decrease yield provided by chlorimuron, imazaquin, or imazethapyr.
Interrelations of Tillage and Weed Control for Soybean (Glycine max) Production
Authors: Webber Charles L. , Kerr Harold D. , Gebhardt Maurice R.
Published: May 2019

A 3-yr (1982, 1983, and 1984) study was conducted to determine the relationship between tillage and six weed control treatments for soybean [Glycine max(L.) Merr. ‘Williams 79′] production on silt loam (Udollic and Mollic Ochraqualfs). Conventional tillage consisted of spring moldboard plowing and secondary tillage with a combination tool just before planting. No-tillage consisted of a foliar application of glyphosate [N-(phosphonomethyl)glycine] at the time of planting. Weed control treatments included combinations of no weed control with and without soybean plants, preemergence herbicide application only, postemergence herbicide application only, and combined preemergence and postemergence applications with and without additional handweeding. In 1982, a year of above-normal seasonal rainfall, conventional tillage had significantly greater soybean grain yields than no-tillage for all weed control treatments except the preemergence-only treatment. Yields within tillage systems and between weed control treatments in 1982 were not significantly different because adequate rainfall reduced the effect of weed competition for soil moisture. Soybean seed yields in 1983 and 1984 in no-tillage were equal to or significantly greater than those of conventional tillage. No-tillage treatments had greater soil moisture conservation and soil moisture availability resulting in less plant water stress during podfilling in periods of drought in 1983 and 1984. In all 3 yr, conventional tillage had significantly greater early weed growth than no-tillage in the treatments with and without soybean plants where no preemergence or postemergence herbicides were used. Comparing treatments with and without soybean plants indicated an average increase of 36 and 38% weed control for no-tillage and conventional tillage, respectively.
Tolerance of Soybean (Glycine max) and Sunflower (Helianthus annuus) to Fall-Applied Dicamba
Authors: Magnusson Mark U. , Wyse Donald L.
Published: May 2019

The influence of fall (late September or late October)-applied dicamba (3,6-dichloro-2-methoxybenzoic acid) on spring-planted soybean [Glycine max(L.) Merr.] and sunflower (Helianthus annuusL.) was studied at five sites in Minnesota during 1983 and 1984. At the two southern Minnesota locations, only late-October applications of dicamba at the highest rate (4.5 kg ae/ha) reduced yields of spring-planted soybean and sunflower. At the central and the two northern Minnesota locations, both late-September and late-October applications of dicamba at 1.1 kg/ha and higher caused injury and yield reductions to soybean and sunflower planted the following year. The two southern Minnesota locations had generally higher levels of precipitation, higher temperatures, higher organic matter soils, and lower pH levels compared to the central and northern Minnesota locations. These climatic and soil characteristics reduced dicamba persistence at the two southern Minnesota locations.
Microbial and Photolytic Dissipation of Imazaquin in Soil
Authors: Basham G. W. , Lavy T. L.
Published: May 2019

Microbial degradation of imazaquin {2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-3-quinolinecarboxylic acid} was monitored by measuring14CO2evolution for 7 months under controlled laboratory conditions. Up to 10% of the14C chain-labeled imazaquin that was applied to a Crowley silt loam was evolved as14CO2in 7 months. Less evolution of14CO2occurred on a Sharkey silty clay, a soil with higher clay and organic matter content, than on silt loam soils. The loss of 66 to 100% of the imazaquin applied to a Crowley silt loam incubated for 8 months at 18 C or 35 C, respectively, suggested that metabolic changes in addition to CO2evolution were occurring. Rapid loss of imazaquin phytotoxicity occurred when soils were held at warm-moist (35 C and −33 kPa) conditions conducive to microbial growth. Imazaquin was more persistent in soils stored under cool, dry (18 C and −100 kPa) conditions. Imazaquin on a soil surface dissipated rapidly when exposed to ultraviolet light or sunlight. Photodecomposition could be a major mode of imazaquin dissipation if this herbicide is allowed to remain on the soil surface.
PROBLEMI E SCELTE NELLA COMPARAZIONE. INTRODUZIONE
Authors: Morlino Leonardo
Published: May 2019

Introduzione

Primo esempio: negli ultimi quindici anni la democrazia sembra essersi affermata in diverse aree del mondo, dal Sud Europa all'America Latina, all'Est Europa; ma quali democrazie si sono realmente affermate e come spiegare complessivamente questo fenomeno?Secondo esempio: durante il 1989 e gran parte dell'anno successivo vi sono state le trasformazioni dei regimi non democratici in Europa Orientale; quali profondi cambiamenti politici vi sono effettivamente stati in quei paesi, oltretutto a un ritmo così rapido?Terzo esempio: in Italia, durante gli ultimi quaranta anni il partito comunista è stato piò forte di quello socialista; come spiegarlo?Quarto esempio: di fronte ai problemi di rappresentatività e democrazia che l'Italia ha, molti politici e intellettuali propongono certe riforme istituzionali; ma quali riforme sono le piò adatte rispetto a determinati obiettivi, quali accrescere la responsabilità dei governanti e la capacità di punizione dei governati oppure raggiungere maggiore efficacia decisionale o ancora riuscire ad innescare l'alternanza al governo tra partiti o coalizioni partitiche?
COMPARAZIONE E WELFARE STATE: UN CASO DI SUCCESSO?
Authors: Ferrera Maurizio
Published: May 2019

Introduzione

Riguardando l'abbondante letteratura dell'ultimo trentennio in tema di welfare state, non si può fare a meno di riconoscere che questo settore d'indagine ha dato luogo ad un progresso conoscitivo davvero notevole, soprattutto per quanto riguarda la sequenza causale che ha originato le politiche sociali verso la fine del secolo scorso e ne ha successivamente promosso una continua e sostenuta espansione. Per avere una conferma immediata di tale progresso è sufficiente un rapido confronto fra lo «stato dell'arte» all'inizio degli anni ‘60 e la situazione attuale. Trent'anni or sono, la stessa etichetta di «welfare state» era fresca di conio nel linguaggio politico, mentre in quello accademico era impiegata dai soli studiosi anglosassoni in riferimento pressoché esclusivo all'esperienza britannica. Pochi gli studi di vasto respiro e tutti di taglio storico, mentre l'incipiente ricerca sociologica era soprattutto assorbita dall'indagine micro-applicativa. Anche se già ben cospicua in tutti i paesi sviluppati, la «cosa» welfare state restava praticamente sconosciuta al di fuori della cerchia ristretta dellaLondon Schoole di pochi altri istituti universitari.
IL PARLAMENTO IN ITALIA. VECCHIE E NUOVE IPOTESI DI RICERCA
Authors: Morisi Massimo
Published: May 2019

Introduzione

Il parlamento è tra le istituzioni più studiate, anche in Italia, tuttavia, la ricerca empirica sul suofunzionamentoall'interno del sistema politico, pare languire da anni. Riempiremmo pagine se dovessimo elencare la miriade di lavori di «riflessione» sull'azione dellegislativo, sulle sue modalità e sui suoi stessi significati sistemici, nel breve come nel medio e lungo termine. Altre pagine ci vorrebbero per dar conto delle molteplici esperienze di ricerca empirica, maturate in un denso e continuo confronto fra ipotesi metodologiche diverse, mono e interdisciplinari, sia in concorrenza che in collaborazione tra diritto costituzionale, storia parlamentare, scienza politica, sociologia politica. E agli studi sulla collocazione e sul ruolo delle assemblee parlamentari all'interno del sistema politico, si potrebbero aggiungere i diversi filoni di ricerca sulla classe politica e sulla rappresentanza.
LA DIFESA EUROPEA: PROBLEMI E PROSPETTIVE
Authors: Gori Umberto
Published: May 2019

Introduzione

Dopo oltre un quarantennio di «politica dello struzzo», o — al massimo — di tentativi falliti, gli Stati dell'Europa occidentale cominciano dolorosamente a rendersi conto che non è più possibile continuare a rimuovere dall'agenda delle priorità il problema della sicurezza e della difesa.